This PDF file contains the front matter associated with SPIE Proceedings Volume 7375, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing

In this paper, we validate experimentally the potential of off-axis digital micro-holography for 3D image reconstruction of a live Human Embryonic Kidney 293(HEK293) cell that is widely used as transfection and expression. A subtraction method of two off-axis holograms to reconstruct the phase of the live microscopic object is discussed. The presented subtraction method can remove some main noise, for example, the quadratic phase aberration introduced by microscope objective (MO), other phase aberration introduced by the liquid in tank and other interference noise introduced by the optical parts. Thus an improvement in the measurement precision of live cells in aqueous solution is observed. The potential of this method is demonstrated by providing the phase reconstruction results of a phase grating and a single HEK293 cell. The results showed good correspondence to the actual character of HEK293 cell prove the capability of digital micro-holography as a tool to monitor the dynamic transfection process of the living HEK 293 cells.

Extended finite element method (X-FEM) is a new method to solve the discontinuous problems, the basic theory of XFEM is presented in this paper, then the X-FEM is used to simulate the crack growth process of the hydroxyapatite material by three points bending test, and its deformation and stress field distribution is analyzed. The numerical results show the effectiveness of the method, the mesh in extended finite element method is independent of the internal geometry and physical interfaces, such that the trouble of high density meshing and re-meshing in the discontinuous field can be avoided. This greatly simplifies the analysis of the crack propagation process, showing the unique advantages of the extended finite element method in fracture expansion analysis of bioceramic. We also propose a two-scale strategy for crack propagation which enables one to use a refined mesh only in the crack's vicinity where it is required.

Two types of sectioned tooth-like ceramic crowns (IPS Empress 2) were prepared along lingual-facial direction and the fracture process of crowns under contact load was directly monitored with the use of imaging system. The displacement filed resulted from digital image correlation indicate that the fracture mode of real crown is more complicated while the flat crown has the same rupture mode as described by other investigators. Meanwhile numerical simulation was also carried out to support the experiments. Stress distributions in individual layer and interface were presented. Results indicate that the presented experimental and numerical methods are efficient in studying the fracture mechanism of all-ceramic crowns.

In this study the deformation in dentin and enamel resulting from the onset of dehydration was quantified using microscopic Digital Image Correlation (DIC). The objectives of the study were to quantify the dimensional changes in dentin and enamel at the onset of dehydration, to examine the anisotropy in deformation, and to identify if there are differences in dehydration related behavior of these tissues associated with patient age. Human premolars and molars were obtained from participating dental clinics in hospitals around Shanghai, China. The teeth were sectioned bucco-lingually using a slow speed diamond saw under continuous water-based coolant. Dentin and enamel were separated along the dentin-enamel junction (DEJ) and contained in Hanks Balanced Salt Solution (HBSS) until test. Then specimens were placed on a precision mass scale with resolution of 0.1 mg to measure the mass loss under air convection in room temperature. The surface images were acquired with a microscopic imaging system and the strain of the specimens (dentin and enamel) in two orthogonal directions, i.e. parallel and perpendicular to the dentin tubules and enamel prisms were analyzed. Results show that both tissues underwent shrinkage with water loss in the two orthogonal directions and regardless of age. The magnitude of strain within the enamel is lower than that within the dentin. The young dentin exhibits an anisotropic response with water loss where the largest shrinkage takes place perpendicular to the dentin tubules, while the shrinkage in old dentin is essentially equivalent in the two directions.

An advanced SMART TAPE system has been developed for real-time in-situ monitoring and long term tracking of structural integrity of pressure vessels in liquid rocket engines. The practical implementation of the structural health monitoring (SHM) system including distributed sensor network, portable diagnostic hardware and dedicated data analysis software is addressed based on the harsh operating environment. Extensive tests were conducted on a simulated large booster LOX-H2 engine propellant duct to evaluate the survivability and functionality of the system under the operating conditions of typical liquid rocket engines such as cryogenic temperature, vibration loads. The test results demonstrated that the developed SHM system could survive the combined cryogenic temperature and vibration environments and effectively detect cracks as small as 2 mm.

Multi-physics multi-scale modeling issues in various stages of the LED manufacturing such as MOCVD reactor design, epitaxial growth based on silicon wafer, chip design and manufacturing, module packaging and assembly have been discussed, which are critical to LED fabrication. In order to enhance the LED design and fabrication efficiency, we propose a new concept to integrate multi-physics/multi-scale modeling as a simulation platform to assist LED design and fabrication. It is indicated that the simulation that relies on multi-physics/multi-scale modeling has the potential to significantly reduce development costs and optimize the fabrication processes of LED

The strain field of an edge dislocation in silicon was experimentally investigated. High-resolution transmission electron microscopy and geometric phase analysis were used to map the strain fields of the edge dislocation. The strain measurement results were compared with the Peierls-Nabarro dislocation model. The comparison shows that the Peierls-Nabarro model is an appropriate theoretical model to describe the strain fields of edge dislocation in silicon.

This paper adopted Kevlar-29 fiber monofilament embedding technology to prepare fiber/ epoxy resin tensile specimen. The specimen was pulled on a homemade and portable mini-loading device. At the same time micro-Raman spectroscopy is introduced to detect the distributions of stress on the embedded fiber at different strain levels. The characteristic peak shift of the 1610 cm^-1 in Raman band has a linear relationship with the strain or stress. The experimental results show that the fiber axial stress decreases gradually from the embedded fiber-start to the embedded fiber-end at the same strain level. At different strain levels, the fiber axial stress increases along with the applied load. It reveals that there is a larger fiber axial stress distribution under a larger strain level. And the stress transfer is realized gradually from the embedded fiber-start to the fiber-end. Stress concentration exists in the embedded fiber-end, which is a dangerous region for interfacial debonding easily.

The stress-strain fields for composite laminate [±25]_S4 containing a circular hole under uniform axial extension are investigated using numerical and experimental methods in this paper. The distributions of normal strain along the length direction around the hole on the specimen surface are measured using digital speckle correlation method (DSCM). Meanwhile, only the middle part of the laminate is taken into account to perform finite element (FE) analysis. For the side face of specimen, a tiny area (1.8mm x 2.4mm) over the hole is chosen to measure the normal strain and shear strain. The experimental results are in a good agreement with FE simulation. Additionally, the interlaminar stress analysis on the hole edge has been performed by FE method.

The determination of large strain isotropic hardening elasto-plastic constitutive model was studied by using solid circular shaft torsion test when taking into account Swift effect of specimen which showed permanent axial length changes in torsion of a solid shaft with free end. Jaumann stress rate of Kirchhoff stress was employed in large strain constitutive model. The deformation rate and Jaumann stress rate were derived, respectively, for free-end torsion deformation and fixed-ends torsion deformation of a solid circular shaft in the large strain range, and the plasticity rigidity function of constitutive model was formulated by the aid of the true shearing stress-shearing strain relationship, axial elongationshearing strain relationship and axial normal stress-shearing strain relationship obtained from solid circular shaft torsion test. The results show that both the axial elongation in free-end solid shaft torsion and the axial normal stress developed in fixed-ends solid shaft torsion has an effect upon large strain constitutive models, and the margin of the effect is mainly related to the slope of axial extension rate-shearing strain curve, the axial normal stress value and the slope of axial normal stress-shearing strain curve.

A nanoscale experimental study of micro-crack in silicon was presented by using a combination of high-resolution transmission electron microscopy and geometric phase analysis. The results show that there is an amorphous phase content in the crack body. The width of the amorphous narrow band which exists within the crack body is 2nm approximately. The geometric phase analysis technology was applied to calculate the strain fields of the crack tip. The trend of the experiment strain value ahead of the crack tip is the same with the trend of the isotropic elastic theory strain value.

Circular and radial gratings are used in digital moiré method in order to obtain in-plane displacement and strain information denoted in polar coordinate system directly. Four-step phase-shifting technique is achieved by shifting the computer-generated reference radial and circular gratings precisely. Basic procedures of this novel digital moiré method with circular and radial gratings are explained in detail by an experimental application for large deformation analysis on a double-cracked rubber disk. By using deformed gratings, radial and circular displacements distributions are measured and distributing information of strains can also be calculated. Results of the application show that the present digital moiré technique of circular and radial gratings is a valid and efficient way in measurement of both displacement and deformation for large deformation materials.

To avoid the complexity of modeling frost heave from microscope, porosity rate function has been used in predication of frost heave phenomenon. The approach explored in this paper is based on frost heave tests and the concept of the segregated potential which has been widely accepted by researchers in order to find the proper form of the porosity rate function. In the frozen fringe the porosity rate function was derived: n^•=Be^(-aP_e) (gradT)² (1-n) , (T_s<T<T_i). It showed that the primary influencing factor affected porosity rate is temperature gradient rather than temperature, it is more reasonable to consider the influence of the temperature gradient in the frozen fringe rather than in the whole column. Then development of the constitutive model is outlined. Five freezing tests were carried out to verify the model, and the comparison between test results and analog results shows that the modified model is efficient for the prediction of frost heave, and it can be used in engineering practice.

Metallic gasket seals have been widely used in chemical and petrochemical plants. The failure of sealing system will lead to enormous pecuniary loss, serious environment pollution and personal injury accident. The failure of sealing systems is mostly caused not by the strength of flanges or bolts but by the leakage of the connections. The leakage behavior of bolted flanged connections is related to the gasket contact stress. In particular, the non-uniform distribution of this stress in the radial direction caused by the flange rotational flexibility has a major influence on the tightness of bolted flanged connections. In this paper, based on Warters method and considering the operating pressure, the deformation of the flanges is analyzed theoretically, and the formula for calculating the angle of rotation of the flanges is derived, based on which and the mechanical property of the gasket material, the method for calculating the gasket contact stresses is put forward. The maximum stress at the gasket outer flank calculated by the analytical method is lower than that obtained by numerical simulation, but the mean stresses calculated by the two methods are nearly the same. The analytical method presented in this paper can be used as an engineering method for designing the metallic gasket connections.

Deformation characteristics of polycarbonate sheet in viscous pressuring bulging are investigated by photoplastic method in this paper. Strain distribution of specimens with different heights was obtained through isochromatic fringe patterns. The shape of the specimen was axisymmetric hemisphere and the directions of the three principal strains were approximately along the longitudinal, latitudinal and thickness directions, respectively. As the tangent plane can be regarded as the principal plane, an approach was represented to calculate the principal strains of the specimen with no need to cutting slices. The specimen was rotated in the polarized light field to obtain isochromatic fringe patterns with different incident angles. Strain values were calculated using oblique incidence method and the results were in good agreement with that measured by the grid method. Photoplasticity is a feasible nondestructive full field analysis method for qualitative and quantitative investigation of sheet deformation.

Loading test method is a tool for checking and assessing bridge structural active state. By dynamic and static loading test the responses of bridge can be obtained, which can be used to assess the practical carrying capacity and stress performance of structures. The loading test is the most reliable method for assessing the performance of bridge. The static tests usually need more time and cost. But bridge ambient vibration test has an advantage of being simple, fast and cheap, which can be implemented simply by measuring the responses data. The ambient vibration test has been widely used in bridge structural detection. This paper will put forward a new analysis method which will forecast the structural static characters by the dynamic parameters of structures. This method can reduce the loading test cost. The structural performance can be forecasted simply by the dynamic parameters. First of all, the structural dynamic parameters, for example frequencies, damping and model shape, can be obtained from the ambient test of structures. Then the relation between the static characters and dynamic parameters will be established. Finally the static performance can be forecasted by the dynamic parameters.

Natural frequencies and modes of Nipper Mechanism on Comber in motion are studied in this paper with emphasis on the effects of gyroscopic effects. They are assumed to be different from those calculated based on assumptions of instantaneous structure, neglecting the coupling of rigid body motion and elastic deformation, and so on, which is not examined. In this study, finite element method is applied to simulate flexible links with those assumptions dropped and gyroscopic effects is thus included due to the consideration of the coupling of rigid body motion and elastic deformation. State space approach is applied to translate the second order differential equations into the first order with double degrees of freedom. Because of the positive definition of global mass and stiffness matrix, Cholesky can be used to obtain the standard gyroscopic eigenvalue equations which can be solved easily. Comparisons show that natural frequencies affected by gyroscopic effects are growing quickly with the speed increasing, especially for the third natural frequency which is much higher than that of simplified model. Therefore, much care needs to be taken when calculating frequencies of mechanisms with high speeds and light weight.

In this paper, numerical analysis has been applied on the body of 10000 t/d rotary kiln by using finite-element method under the cold condition. Mesh self-adapting technology was used during the course of numerical solution. Modeling, defining of material property, solving and post-processing were all realized by using ANSYS Parametric Design Language (APDL). Stress and deformation under the actual condition were presented by calculating without considering temperature effect. Thus, it's easy to simulate the stress and deformation distribution under various working condition, and it provides academic instruction for design and adjustment of rotary kiln.

Modal parameter identification is the critical component for structural damage detection and structural health monitoring. Although a lot of identification algorithms have been developed, there are still some problems in terms of their accuracy and effectiveness. For example, for rational fractional polynomial method and orthogonal polynomial method, which are based on fitting measured frequency response functions, the former is disturbed by ill-conditioned solution and misfit while the latter is obsessed by precision loss with transformation of base function. On the other hand, for algorithms in time domain, such as eigensystem realization algorithm and stochastic subspace identification, construction of Henkel matrix and determination of system order are the main issues with which no general methods to deal up to now. In order to compare the similarities and discrepancies of different modal identification algorithms, the data taken from a shaking table test on a 12-storey reinforced concrete frame model are processed using selected rational fraction polynomial method in frequency domain and eigensystem realization algorithm in time domain. The comparison of the identification results is further discussed.

The construction procedure of Jiangnan University new campus stadium is complex. During the construction process, the complicated load combination, the geometrical shape and boundary of long-span structure are greatly different between the construction process and the normal usage stage. To assure the safety of the construction process, the displacement monitoring analysis is performed on the stadium reticulated shell structure construction. The optical apparatus KONI007 made in France is used in the vertical displacement monitoring process with 2nd level measure precision. The displacement locations are introduced in the paper and the monitoring data process analysis is also done. To investigate the displacement and stress distribution of the roof structure, the three dimensional finite element analyses is performed. The monitoring data analysis and finite element analyses result show that the deformation of the chords are evenly distributed and the elastic support has fewer elastic deformation to decrease the horizontal push force on the concrete column and to adjust the reticulated shell chord internal force. The reticulated shell construction procedure is reasonable.

The state-of-the art of lateral deformation in soft ground under embankment is reviewed in this paper. The problem is usually investigated using the relationship between the maximum lateral deformation and settlement of embankment center. The calculated model is established with finite element method. The computed results show that, during the loading period ▵y_m=▵S and during the period of consolidation ▵y_m=0.15▵S, where ▵y_m and ▵S are the increment of lateral deformation and settlement respectively. The loading consequences also affect the ratio. The effect of parameters of soft soil on lateral deformation is discussed. The calculated results are helpful to the research on the behavior of the lateral deformation.

Conventional sheet metal forming processes are not suitable for flexible small-batch production and, therefore, are not appropriate for the growing agile manufacturing trends requiring very short life-cycles, development and production lead times. In fact, the present need for flexible sheet metal forming techniques requires the development of innovative technological solutions that are capable of reducing the fixed and capital costs of sheet metal forming to a level where small-batch production becomes economically feasible. Single point incremental forming (SPIF) is a new sheet metal forming process with a high potential economic payoff for rapid prototyping applications and for small quantity production. In general terms a typical SPIF set-up makes use of a small number of low cost active tools components; (i) a blankholder, (ii) a backing plate and (iii) a single point forming tool. The tool path is generated in a CNC machining center and during the process there is no backup die supporting the back surface of the sheet. Despite the contributions of many researchers on the development of industrial applications and better characterization of the forming limits of the process, several key topics related to the mechanics of deformation, likely mode of failure, geometric accuracy and surface quality of the formed parts remain little understood and scarcely systematized. This paper attempts to provide new contributions about the abovementioned issues by means of a comprehensive experimental investigation performed under laboratory controlled conditions.

Typical pressure vessel materials' torsion equivalent stress-equivalent strain relationships under large deformation condition are researched in this paper. Because the length and the diameter of the specimen may change under uniaxial tension, it's impossible to make effective measurement and analysis for the mechanical properties of the specimen, especially after the necking. The form and cross-section size of cylindrical specimen do not change in torsion test, so that the large strain's constitutive relationship is more accurate than that obtained from an axial tension test. So that cylindrical specimen's torsion test is attempted to obtain the shear stress-shear strain curves of typical pressure vessel materials 16MnR and Q235. Consider that the stress is non-homogeneous in the cross-section of cylindrical specimen, thin wall tube specimen is also used in the torsion test, and the maximum differences between cylindrical specimen's results and thin-wall tube's are 10% and 13% respectively. Tension true stress-true strain curves, torsion equivalent stress-equivalent strain curves are also compared in this paper and the results showed that description of the torsion constitutive relationship is more complete than that of tension. At last, constitutive equations are fitted and the mathematical representations are obtained.

It's one of the important ways to monitor the change of dynamic characteristic of turbine blades for ensuring safety operation of turbine unit. Traditional measurement systems for monitoring blade vibration generally use strain gauges attached to the surface of turbine blades, each strain gauge gives out an analogue signal related to blade deformation, it's maximal defect is only a few blades could be monitored which are attached by strain gauge. But the noncontact vibration measurement will be discussed would solve this problem. This paper deals with noncontact vibration measurement on the rotor blades of turbine through experiments. In this paper, the noncontact vibration measurement - Tip Timing Measurement will be presented, and will be improved. The statistics and DFT will be used in the improved measurement. The main advantage of the improved measurement is that only two sensors over the top of blades and one synchronous sensor of the rotor are used to get the exact vibration characteristics of the each blade in a row. In our experiment, we adopt NI Company's DAQ equipment: SCXI1001 and PCI 6221, three optical sensors, base on the graphics program soft LabVIEW to develop the turbine blade monitor system. At the different rotational speed of the rotor (1000r/m and 1200r/m) we do several experiments on the bench of the Turbine characteristic. Its results indicated that the vibration of turbine blade could be real-time monitored and accurately measured by the improved Tip Timing Measurement.

The interfacial debonding at the plate ends is the most common failure mode in a carbon fibre reinforced polymer (CFRP) strengthened steel beam due to the high stress concentration there. This paper presents the results of a theoretical and experimental study on the interfacial debonding of the steel beams reinforced with CFRP plates. An analytical solution was developed to calculate the interfacial shear stress between the steel beam and the CFRP plate. The shear stress-slip relation of the bonding layer was simulated by a bilinear model. Three specimens were tested under threepoint bending. Two strain gauges were mounted at the ends of the plate bottom. If the effect of the spew fillet and the normal stress are ignored, the curves of strain recorded from the tests can be simplified to a bilinear model as well, which validates the theoretical results. When the strain is close to zero, the interfacial debonding initiated at the end of the plate. The agreement between the debonding loads obtained from the analytical solutions and the tests is good, which demonstrate that the presented analytical solution can predicate the debonding load correctly.

In this paper, Y-shaped branch pipes are designed with one branch being unchanged and the other being changeable. Gas-Solid flow experiments of average particle diameter 2mm millet are carried out using compress air at horizontal Yshaped branch pipe. Resistance properties of each branch and the mutual resistance characteristics are described. The results show when the superficial gas velocity reduces, the pressure drop on each branch and the pressure drop differential value of the two branches decrease firstly, but when the superficial gas velocity reduces to deposition velocity, the respective pressure drop begin to rise. With the differential value rising of the angle between the changing branch and the main pipe, it is found that the pressure drop curve of each branch and the pressure drop differential value of the two branch are away from each other in high gas velocity zone, while become near in low gas velocity zone. Meanwhile, principal component analysis method is adopted to explore the importance of influencing factors and their correlation. The experimental consequence shows that the angle between the changeable branch and the main pipe, superficial gas velocity and the solids loading ratio are chief influencing factors.

Continued demand for flexible and sophisticated, yet lightweight and low power as well as small, systems is being satisfied by advances in microelectromechanical systems (MEMS). These advances require use of computational modeling and simulation accompanied by physical measurements. Successful combination of computer aided design (CAD) and multiphysics simulation tools with the state-of-the-art (SOTA) measurement methodology will contribute to reduction of high prototyping costs, long product development cycles, and time-to-market pressures while developing MEMS for a multitude of increasingly diversified applications. In one approach a unique, fully integrated, software environment for multiscale, multiphysics, high fidelity modeling of MEMS is combined with the SOTA optoelectronic laser interferometric microscope (OELIM) methodology for measurements. The OELIM methodology allows remote, noninvasive, full-field-of-view (FFV) measurements of displacements/deformations and vibrations with high spatial resolution, nanometer accuracy, and in near real-time. In this paper, an approach - employing both, the modeling environment (including an analytical process used to quantitatively show the influence that various parameters defining a microstructure, e.g., RF MEMS, a microswitch, or a sensor, may have on its dynamics; using this process dynamic characteristics of a device/sensor can be optimized by constraining its nominal dimensions and finding the optimum set of uncertainties/tolerances in these dimensions) and the OELIM methodology - is described and its applications are illustrated with representative examples. The examples reveal viability of the approach, combining measurements and modeling (i.e., M&M), for the development of MEMS. The representative results demonstrate capacity of the M&M approach to quantitative determination of the effects of dynamic operational loads on performance of selected microstructures of current interest.

A method for whole-field non-contact measurement of displacement, velocity and acceleration of a vibrating microobject based on digital holographic microscopy is presented. A micro-beam is excited by a fluctuating voltage with a sinusoidal configuration. A series of digital holograms are captured using a digital holographic microscope with a highspeed camera. The result of reconstruction is a three dimensional complex-valued matrix with noises. In this paper, Fourier analysis and windowed Fourier analysis are applied in both the spatial and temporal domains to extract the kinematic parameters. The instantaneous displacement is obtained by temporal phase unwrapping of the filtered wrapped phase map, while the velocity and acceleration are evaluated by windowed Fourier analysis along the time axis. The combination of digital holographic microscopy and temporal Fourier analyses is able to study the vibration without a phase ambiguity problem, and the instantaneous kinematic parameters on each point are obtained.

The main objective of this study is to develop a stress-buffer-improved package that is subjected to a board level drop test under a specific-G impact level. In this regard, both the drop test experiment and the ANSYS/LS-DYNA simulations are carried out. Several studies have shown that the solder joints having the brittle intermetallic compound (IMC) layers within the wafer level chip scale packaging (WLCSP) are the weakest part. For the most part, this is due to the large relative motion occurring between the board and the chip. In addition, the stress buffer layer exhibiting a relatively large elongation which reduces the impact on the solder balls. Meanwhile, the novel stress-buffer-improve package's failure mode is different from the convention WLCSP structure which shifts to the trace damage of the chip side. The leading concern between the solder ball and trace damage is the critical region where failure occurred owing to the stress concentration effect. During the drop test experiment, the proposed stress-buffer-improved package is able to survive over 100 drops (most packages survived at above 200 drops). Hence, this drop performance very much surpasses the Joint Electron Device Engineering Council (JEDEC) criterion (drop number is 30 times). Nevertheless, the metal traces which are embedded in the stress buffer layer suffered relatively larger deformation. Generally, the stress concentration occurs at a single position, much like the trace/pad connecting junction in the analysis of detailed stress-buffer-improved package. Finally, the predict result in finite element (FE) analysis is similar to the broken metal trace's failure analysis in the drop test experiment.

One of the important factors resulting in the performances of the machinery is its dynamic characteristics. It will directly influence the final manufacturing capability of the machinery and it is also the important criterion of evaluating machinery performances. The spindle and spindle assembly are the essential parts of the NC machine tool. So it is very important to analyze the dynamic-static characteristic of the spindle assembly and to study the effect on machinery function. This paper's research is based on a NC machine tool produced by a certain Plant of Machine Tools. Methods of simulating the spindle assembly support are studied, and the configuration of the spring damper elements of the bearing supports are also studied, and the FEA on spindle and spindle assembly has been made to confirm its dynamic characteristics. Then the FEA models are validated by some experiments.

Digital speckle correlation method (DSCM) is used to measure the thermomechanical coupling effect in COB packaging structures. During deformation, CCD camera is applied to capture the speckle patterns of CMOS chip at different temperature fields constantly. These speckle patterns would provide the deformation history of the sample. By analyzing the speckle patterns, the in-plane deformation of the CMOS chip is obtained. Based on the trigonometrical theory, outplane displacement can be obtained from in-plane displacement, and then the elastic thermal stress of the chip is evaluated when the application of the temperature field is repeated. Experiment results are compared with both the results of FEM simulation and the theoretical model. There results are agreed well and it can be proved that DSCM can successfully be applied to analyze the thermomechanical coupling effect. The theoretical model was also verified by result of FEM simulation and experiment testing. Experiment results provide an availability consult to the design of MEMS apparatus.

Epitaxial growth behavior of the La_0.5Sr_0.5MnO₃ thin films prepared at different annealing temperatures by Spin-Coating method on a Si(100) substrate have been studied. The thin films have a low resistivity and metallic conducting features. The results reveal that for the epitaxial growth of LSMO thin films, 800°C is the optimal annealing temperature. The structure and surface morphology of the films were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The surface resistance of the films prepared with different conditions was measured by four-point dc method. Emphases are laid on the discussions of the epitaxial growth of the LSMO thin films.

Micro beams are frequently used as executive components in MEMS such as pressure and acceleration sensors, micro switches, and micro resonators. In this paper, the influence of air viscous damping on the dynamic characteristics of a micro beam that oscillates in the air is evaluated analytically. A closed-form solution that can be used to predict the dynamic response of a micro beam is obtained based on a beam model used for evaluating the air viscous damping. The resonant frequencies versus the geometry parameters of a micro beam undergoing the air viscous damping are analyzed. The analysis results show that the influence of the air viscous damping on the resonant frequencies of a micro beam is notable and hence it should be take into account in the design process of MEMS. Moreover, as we know, there are various excitation methods for a micro beam in dynamics such as the electrostatic and PZT methods. The analytical results in our work also show that the influence of air viscosity on the dynamic characteristics of a micro beam will be diverse under different excitation methods.

The experimental research on fatigue crack propagation rate of reinforced concrete (RC) beams strengthened with carbon fiber laminate (CFL) is carried out by MTS system in this paper. The experimental results show that, the main crack propagation on strengthened beam can be summarized into three phases: 1) fast propagation phase; 2) steady propagation and rest phase; 3) unsteady propagation phase. The phase 2-i.e. steady propagation and rest stage makes up about 95% of fatigue life of the strengthened beam. The propagation rate of the main crack, da/dN, in phase 2 can be described by Paris formula, and the constant C and m can be confirmed by the fatigue crack propagation experiments of the RC beams strengthened with CFL under three-point bending loads.

Using carbon fiber laminate (CFL) invented by our group, we take the lead in studying the fatigue behaviors of the beams strengthened with FRP under the cyclic loads. The maximum crack width of the RC beams strengthened with CFL conforms to the law of three-stages, and the main factors which affect the fatigue crack propagation behavior was analyzed. Theoretical analyses are performed for the evolvement rule of maximum crack width of the strengthened RC beams under constant amplitude and random fatigue loads. Then, a method for calculating the propagation rule of maximum flexural crack width under fatigue loads is proposed, based on the initial crack width under static loads and the coefficient of the strain of CFL. This method can be used not only for crack width determination under constant amplitude cyclic load but also the random fatigue load. Using the method, permissive fatigue life can be estimated.

Reflective cracking arising from cracks in base materials has been a major distress of semi-rigid asphalt concrete road. Previous studies in base mixture cracking have typically considered the materials homogeneity. Adopting Digital Image Processing techniques and Finite Element Method, in the micro scale, the cement and aggregates are treated as distinct materials with different materials parameters. The potential crack zones are simulated by Cohesive Zone Model. The initiation and propagation of the crack in the cylindrical specimen under conventional Indirect Tensile Test (IDT) are modeled. The numerical results from the micromechanical analysis match well with the results from the macro experiment. Even though this study only presented a attempt to a numerical simulation of a simple IDT test, the theory and methods adopted by this study can be applied to the fatigue damage scenario under complicated loading conditions including material heterogeneity. It effectively allows researchers to link the micro-scale damage observed on the local scale with the real pavements failing on the global scale.

Honeycomb sandwich structures are significant to be used as applied to thermal protection system on reusable launch vehicle. In this paper the fatigue and impact properties of a novel metallic thermal protection material have been investigated and predicted at room temperature. A series of strength tests are carried out to obtain parameters firstly for further experiments. A set of tension-tension stress fatigue tests and impact tests based on split-Hopkinson pressure bar are carried out. Different high strain rate impact experiments are accomplished. The curves of dynamical stress, strain and strain rate are obtained. Also the cell units images after impact are presented. The results show the fatigue properties of honeycomb sandwich panels are comparatively better. And it has the advantages of anti-impact resistance and high, energy absorption capability.

Crack propagation rate of the interface of fiber reinforced polymer (FRP) bonded to red maple wood, is analyzed and predicted using an artificial neural network (ANN) method. The performance of Multilayer Perceptron (MLP) and Modular Neural Network (MNN) is compared to obtain an optimal ANN model to predict the crack propagation rate. The effect of various parameters of the MNN and MLP models are investigated. The number of input vectors of MLP and MNN models is studied to see if this will affect the training and predicting performance by the scatter of input vectors. At last, a new method called sensitivity analysis is adopted to explore the influenced proportion of the input vectors and the effect of load ratio, frequency, et al., on the crack propagation rate.

A new optimization method based on the fatigue life of multi-body structure is proposed in this paper with the computeraided engineering software. Taking the nose landing gear of some aero transports as an example, the loading history of the nose landing gear is firstly gained by the multi-body dynamics simulation, and then the fatigue life is predicted through the finite element method and fatigue analysis. In accordance with the forecasting results, the weakest parts of the components are identified, and then they are optimized based on the fatigue life to lengthen the fatigue life of structural weaknesses thus to the fatigue lives of the whole structures.

Utilizing GDS unsaturated triaxial apparatus and pressure plate extractor, the tensile crack propagation depth of unsaturated expansive soils is studied. A linear elastic solution of the tensile crack propagation depth is presented and reduced coefficient of effective cohesion is defined. Expressions for critical matrix suction at the ground surface, and the crack propagation depth with no influence of the depth of the groundwater level are derived from the equation of crack propagation depth. Relationships with influencing factors are compared, such as effective cohesion, reduced coefficient of effective cohesion, effective internal friction angle, Poisson's ratio, matrix suction at the ground surface and the depth of the groundwater level. Based on above, the influences of tensile cracks on tension zone depth are analyzed, considering three typical matrix suction profiles along the depth, that is, constant, linear and parabolic distributions.

In this paper, a life testing system of a gun barrel was set up and a set of experiment was used for the diagnostics of gun barrel erosion in rapid-fire condition. The progressive erosion micrographs of the bore surface of a gun tube are obtained by means of a special optical method. Muzzle velocity and the progressive change of the loss of the muzzle velocity in the life time are measured by projectile velocity measurement system. The progressive change of the bore dimensions of the test barrel is monitored. Surface temperature distribution of the gun barrel is measured by the thermocouples. A thermal-solid coupled model of a gun barrel in cyclic firing condition is built and transient temperature field is presented. Theoretical calculations and experimental measurements indicate that heat is transferred from the pulse hot gas to the bore surface by forced convection, further raising the bore surface temperature, which not only reduces the gun mechanical strength, but also promotes chemical interactions. It is one of the key factors of the gun barrel erosion life. New understanding of performance decay and its mechanisms of a machine gun barrel in lifetime are presented.

In this paper, to better understand the spall properties of 6061 Al-Alloy, a combined analysis of experimental and numerical simulation study is conducted. A series of plate impact experiments loaded by gas gun have been performed at a range of velocities required to cause spall planes to grow in these variously heat-treated 6061 Al-Alloy specimens. Two different methods are employed. A commercial manganin stress gauge is sandwiched between the specimens and a buffer material with lower shock impedance (usually PMMA) which is used to determine the stress profiles; without the buffer material, target is well recovered by avoiding any unwanted impact, then the collected specimen is examined under a microscope for charactering fracture damage. The spall strength and the process of spallation are presented from the experimental results. The finite element code LS-DNYA is used to simulate the plate impact testing. The damage distribution and its development in the specimens are given from the numerical results, which is coincided with the experimental results.

The underground caverns that locate in high geostress are being excavated. The surrounding rock masses are prone to appear longitudinal splitting cracks and lead to brittle craze even failure, like rockburst etc, and endanger the safety of engineering. The test of brittle rock and simulation analysis are carried out to study the extension process of splitting cracks and the phenomena of split failure are obtained. The mechanism and conditions are discussed according to the special project phenomena. The results can supply some significant guidance to design and construction of similar engineering.

Applying prestress to fiber reinforced polymer (FRP) can be used more efficiently since a greater portion energy of its tensile capacity is engaged. Based on carbon fiber laminate (CFL), fatigue tests are made to find out the fatigue behavior of reinforced concrete (RC) beams strengthened with prestressed CFL. The interfacial debonding is a main failure mode for RC beams strengthened with prestressed CFLs under the cyclic loading. Furthermore, it has been found that the stress value of CFLs decide whether the additional prestressing has a negative or positive effect on the fatigue behavior of the strengthened beam, and the excessive prestressing would reduce the fatigue life of the strengthened beam.

Fiber reinforced composites are applied broadly in aeronautic and astronautic fields as a structural material. But the investigation in dynamic fracture behavior of fiber reinforced composite stands in the breach for scientists due to a large number of aircraft disasters. In this paper, the mixed mode fracture problems in fiber reinforced composites under impact are studied. First, based on the theory of the reflective dynamic caustic method for mixed mode fracture, corresponding experiments are carried out to study the dynamic fracture behaviors of unidirectional fiber reinforced composites under two kinds load conditions. By recording and analyzing the shadow spot patterns during the crack propagation process carefully, the dynamic fracture toughness and crack growth velocity of fiber reinforced composites are obtained. Via the observation of the crack growth routes and fracture sections, we further reveal the fracture mechanism of unidirectional fiber reinforced composites. It concludes that opening mode still is the easier fracture type for the pre-crack initiation in fiber reinforced composites, while the interface between fibers and matrix becomes the fatal vulnerability during the crack propagation.

In order to contribute to the development of a methodology for risk assessment (fatigue reliability) and lifetime prediction for safety critical metallic components, the risk assessment and lifetime prediction for critical metallic components are studied. First order reliability method (FORM) is used and application to weep hole cracks in C141 wing is analyzed. A novel method of fitting a closed form mathematical expression for probability of detecting (POD) to experimental C-scan data from C141 weep holes was used in the analysis. FORM methods are combined to compute fatigue reliability for the weep hole configuration. The method shows promise for development as a standalone personal computer based system for structural integrity and reliability assessment.

The PMMA model transmission-type experiment of dynamic caustics was carried out to simulate the fracture blasting process of material containing pre-existing flaws using the dynamic caustic-test system. The mechanism of the fracture coalescence among four prefabricated flaws with echelon geometry distribution was studied under blast loading. The experiment results show that two wing cracks respectively coalescing with the flaw F2 and flaw F3 appear at both tips of the flaw F1 closest to the blasthole. Whereas the flaw F4 doesn't produce wing cracks, the flaw F2 and flaw F3 also respectively generate two wing cracks which don't link up the flaw F4. Crack propagation is greatly affected by preexisting flaws. During the whole fracture process, the wing crack velocity oscillates with the increase of crack propagating time. The value of dynamic stress intensity factor reaches the maximum in a moment and then gradually decreases. The changes of dynamic stress intensity factor also oscillate in the whole time. Furthermore, the value of dynamic stress intensity factor K^d_II is smaller than that of dynamic stress intensity factor K^d_I. The results of the present research can provide the theoretical basis for the study on blasting of rock containing flaws.

Based on the observation that high stress results in increasing creep rate of polymeric material, which is analogous to the time-temperature equivalence, where high temperature accelerates the process of creep or relaxation of polymer, the time-stress equivalence is investigated. The changes of intrinsic time in polymer induced by temperature and stress are studied using the free volume theory, and a clock model based on the time-temperature and time-stress equivalence is constructed to predict the long-term creep behavior of polymer. Polypropylene is used for this work. The specimens with shape of dumbbell are formed via injection molding. The short-term creep tests under various stress levels are carried out at ambient temperature. The creep strains of specimens are modeled according to the concept of time-stress equivalence, and the corresponding stress shift factors are calculated. A master creep curve is built by the clock model. The result indicates that the time-stress superposition principle provides an accelerated characterization method in the laboratory. Finally, the time-dependent axial elongations at sustained stress levels, whose values are close to the tensile strength of polypropylene, are measured. The three phases of creep, i.e., the transient, steady state and accelerated creep phases, are studied, and the application and limitation of the time-stress superposition principle are discussed.

The threshold in fatigue crack propagation (▵K_th), which is a principal indicator of the property resistant to fracture of members bearing crack defect during the process of corrosion fatigue, plays an important role in engineering project. ▵K_th cannot be directly obtained from test methods due to the accurate measurement of crack extension could not be conducted with the current test methods. The over-and-under method of fatigue reliability theory is innovatively introduced into the test determination of ▵K_th. Meanwhile, a flatbase for the determination of ▵K_th in low cycle fatigue H₂S environment is set up. Additionally, data analysis is conducted by the way corresponding to the over-and-under method. The results show that: 1) The test determination of ▵K_th can be effectively obtained through the test flatbase of corrosion fatigue. 2) The accurate measurement and study of ▵K_th in low cycle fatigue H₂S environment is realized by the over-and-under method of fatigue reliability theory. 3)The ▵K_th in air environment is obviously greater that the one in low cycle fatigue H₂S environment, where they differ by more than 50%.

Under the action of tensile load obvious necking-down phenomena will occur in the metal test-piece. The tensile experiment about the metal test-piece has been studied, but the finite element simulation of the tensile necking-down phenomena has not been reported. The paper first studies the experiment of the mental test-piece, using the universal testing machine of WE-10A and WI-60T to load the mental test-piece and using IZ-910 infrared thermal imager to test the change process of infrared radiation temperature fields, then works out the finite element program to simulate the tensile necking-down phenomena of the metal test-piece with the elastic-plastic model. The experiment result shows that the infrared thermal effect of the metal test-piece in the process of loading is obvious, before the sample fracture will appear the omen of high temperature in the position where the future fracture will occur; in stress concentration the microcracks concentrate and the thermal figure is obvious; in the whole loading process the fracture starts from the local part, develops and evolutes gradually; with the stress change on the metal test-piece the infrared radiation temperature of the test-piece surface changes, having the temperature-rising tendency in the total and the temperature rising trend in the local fracture position is obvious. This is because the metal test-piece material or the force is uneven and the stress concentration is formed, In the position of the stress concentration the deformation destruction firstly occurs. Because the energy is released in the process of deformation destruction, so the temperature change is obvious in the fracture position. After the experiment the obvious necking-down phenomena occurs in the test-piece. At the same time, in order to provide the theoretical basis for the experiment, with the finite element software of FEPG the finite element program is worked out, with the elastic-plastic model and the uneven material the fracture evolution process of the metal test-piece is simulated. Through the comparison we can see that obvious necking-down phenomena appeared in the metal testpiece under the tensile load, the infrared information testing shows the temperature-rising is obvious in the position where necking-down phenomena occurs and the tensile necking-down phenomena of the metal test-piece is well simulated, which can provide helpful basis for the prediction and forecast of mental structure fracture.

Integral shroud is an advanced technique used to improve reliability of steam turbine blades. In this paper, dynamic characteristics of vibration-impact process of steam turbine blades with integral shroud are studied. To test and verify the reliability of calculation result, a series of experiments are well performed on the platform of contracting and impacting of blades tips. The dynamic strain data under different gaps, different loads and different rotating speeds are surveyed through which the log decrement at each condition is obtained, and the effects of vibration damping are obtained by comparing the log decrement. The results of experimental study show that larger log decrement means larger system damping and better effectives of vibration reduction. Besides, the effects of vibro-impact reduction of different parameters are got and the experimental study results show that the vibro-impact structure is a good vibration damper. The dynamic stress of the blade with integral shroud is insensitive to loads when the gap between adjacent integral shrouds is small. In short, the achievements gained in the paper have revealed dynamic characteristics for vibro-impact process of steam turbine blades with integral shroud, which will bring important engineering application to development and modification design of the integrally shrouded blades.

Automated production of, in the sense of, machine production has characteristic features: a reduction of production costs, stimulation of the development of cutting tools, and changes in the construction of machine tools, all of which work against the creation of optimal technological methods, which thrusts the technological process of cutting into a more important position. These trends confirm that the cutting process remains one of the basic manufacturing technologies. A condition of the economic usage of modern, automated programmed drilling machines is the optimal course of the cutting process, i.e. the use of optimal work conditions. A summary of optimal work conditions requires knowledge of the laws of cutting theory and knowledge of the practical conditions of their application. This article presents the results of experiments that concerned the verification of machinability of work pieces of difference types of X12CrNi 18 8 austenitic stainless steel. Steel X12CrNi 18 8 is the chief representative of the austenitic stainless steels, and this steel falls into the category of materials that are difficult to machine. The rapid development of industry is marked by the development and application of new materials with characteristics that broaden their applicable uses. Precise and reliable information on the machinability of a material before it enters the machining process is a necessity, and hypotheses must be tested through verification of actual methods. This article presents conclusions of machinability tests on austenitic stainless steels and describes appropriate parameters for the cutting zone during the process of drilling with the goal of proposing recommendations for this steels, and to integrate current knowledge in this field with drilling and praxis. This article concerns itself with the evaluation of selected domains of machinability in compliance with EN ISO standards. The experiments were performed in laboratory conditions and verified in real conditions during manufacture. The set-up used contained the following components: a turning machine with gas regulation of rotational frequency, a cutting tool with M20 cutter.

Three types of asphalt mixtures, including asphalt concrete (AC), stone mastic asphalt (SMA) and porous asphalt (PA) with a 13mm gradation, are chosen to study the fatigue behavior, linear contraction and creep performance of them. The analysis of the experimental results is summarized as follows. The asphalt mixture exhibits longer fatigue life at low temperature than that at high temperature. But the fatigue life is more sensitive to the loading stress at low temperature. At the same time, the fatigue lives of all the three mixture gradations show decreasing trends with the increasing stress, which implies that restraining over-loading of highways is quite important. The linear contractive quotiety shows great distinction with the types of asphalt mixture gradations and temperature span, which indicates that modified asphalt and lower air voids can benefit to the contractive properties of asphalt mixtures at low temperature. Additionally, the linear contractive quotiety decreases with the falling of the temperature, meanwhile the distinctions between different temperature spans tend to slower. The creep test indicates that lower air voids and larger asphalt content are beneficial to the low temperature performance of asphalt.

Two vacuum carburizing treatments were applied to ductile steel 14NiCr11 to obtain equivalent hardened layers with retained austenite contents of 25% and 41%. The properties of the carburized surfaces were examined and characterized before fatigue tests and during cyclic loading. Transformation of retained austenite into martensite during loading, was evaluated by dispersive X-ray diffraction method. The effects of this transformation on the residual stresses have been measured by X ray diffraction in martensite and in retained austenite structures. It was shown that the cyclic retained austenite transformation caused a redistribution of the compressive residual stresses and an increased surface hardness that stabilized after a small number of cycles. The dependence of fatigue behaviour on surface properties was determined, and a relationship between the stabilized state and the fatigue limit is suggested. A phenomenological approach is proposed to correlate the influence of surface hardening and the stabilized residual stresses on fatigue limit of carburized specimens. The Crossland, Dang Van and Findley-Matake, multiaxial high cycle fatigue criteria were used in this approach and results have shown a good agreement with experimental data.

The ratcheting behaviors and fatigue failure, as well as their interaction were investigated by uniaxial cyclic stressing tests for 20 carbon steel at room temperature. The ratcheting strain and fatigue life of the material were measured in varied loading levels. The effects of mean stress, stress amplitude and stress ratio on the ratcheting strain and final failure life were discussed. The experimental results show that the ratcheting strain and fatigue life of the material greatly depend on mean stress, stress amplitude and stress ratio in asymmetric stress cycling, and two kinds of failure modes (i.e., ratcheting failure due to large ratcheting strain and fatigue failure caused by the fatigue crack) occur respectively, depending on the applied stress level in the tests.

A mechanical model of cracked reinforced concrete (RC) beams strengthened with carbon fiber laminate (CFL) is proposed to establish the theoretical relationship among the crack height (a), the number of fatigue loading cycles (n), and the fatigue life (N), and the main crack growth behavior is discussed. Moreover, some fatigue tests of the RC beams strengthened with CFL were carried out on material testing system (MTS) to investigate the crack growth rate (da/dn). The analysis results show that the crack growth behavior of RC beams strengthened with CFL may be divided into three stages: 1) initiation and rapid growth, 2) steady growth and arrest, 3) unstable growth. At the stage of crack steady growth and arrest, the relationship among, da/dn, n, and N could be expressed as: da/dn=C/(nlnN), where the constant coefficient, C, is determined from the fatigue tests.

Two specimens along different directions are cut from directional Plexiglas plate of biaxial tension. Digital image correlation method in frequency domain is applied to measure elastic modulus. Through analysing elastic modulus along different directions, directional Plexiglas is anisotropic material. Because of the anisotropic mechanical behaviors in directional Plexiglas, the values of fracture toughness are related to the propagation directions of cracks. The specimen is very small, so there is not enough space to put the extensometer. Digital image correlation method in frequency domain which substitutes the extensometer is applied to test crack opening displacement V. In the paper fracture toughness values are tested along two directions. Experiment results indicate that the cracks of different propagation directions have different fracture mechanics properties.

A modified Split Hopkinson Pressure Bar technique with aluminum pressure bars and a pulse shaper technique to achieve a closer impedance match between the pressure bars and the specimen materials such as hot temperature degraded POM (Poly Oxy Methylene) and PP (Poly Propylene). The more distinguishable experimental signals were obtained to evaluate the more accurate dynamic deformation behavior of materials under a high strain rate loading condition. A pulse shaping technique is introduced to reduce the non-equilibrium on the dynamic material response by modulation of the incident wave during a short period of test. This increases the rise time of the incident pulse in the SHPB experiment. For the dynamic stress strain curve obtained from SHPB experiment, the Johnson-Cook model is applied as a constitutive equation. The applicability of this constitutive equation is verified by using the probabilistic reliability estimation method. Two reliability methodologies such as the FORM and the SORM have been proposed. The limit state function(LSF) includes the Johnson-Cook model and applied stresses. The LSF in this study allows more statistical flexibility on the yield stress than a paper published before. It is found that the failure probability estimated by using the SORM is more reliable than those of the FORM/ It is also noted that the failure probability increases with increase of the applied stress. Moreover, it is also found that the parameters of Johnson-Cook model such as A and n, and the applied stress are found to affect the failure probability more severely than the other random variables according to the sensitivity analysis.

There has been a lot of attention recently on space inflatable deployment structures. One of the challenges is to control the dynamic properties of the structures during the inflation and deployment. Inflatable tubes used to deploy and support space structures are a key component for many space inflatable structures. In this paper, an inflation deployment experimental system in equivalent micro gravity environment is established based on air track which evidently avoid disturbance of contact sensor to the inflation deployment process. The impact of dynamic properties from three different kinds of gas flow, variable geometry size and if there is added mass on deployable end. Dispersion of the experimental data is analyzed. The experimental results indicate that the inflation deployment experimental system in equivalent micro gravity environment is feasible and effective. Results also show that deployment velocities of the folded tube are a function of the tube diameter, gas flow, and the added mass on the deployable end.

A dual simultaneous photometric-conductometric detector for microfluidic chip is reported. Two different detect methods confocal LIF and moveable C⁴D were combined together. They shared a common detection cell and could respond simultaneously. The dual detector offered possibility of measurement one analyte in two different ways and was advantageous in analyses of mixtures containing organic and inorganic ions. To improve the separation efficiency, pinch injection was carried out by a series of electrokinetic manipulations. Rhodamine B was used to evaluate the performance of the dual detector. The dual detector had highly sensitivity and could offer simultaneous information.

In this paper, a combined measurement technique of Particle Image Velocimetry (PIV) and shadowgraph is proposed to investigate the environmental fluid dynamics. This measurement system is based on a PIV system, with a backlight added to produce the shadow of dyed water. The images recorded by a CCD camera are then processed for the PIV and shadowgraph data, separately. The experimental results show that this technique is well suitable for the investigation of time-dependent flow field with temperature variation. Fairly good agreements with the experimental and CFD results are achieved.

Combined buoyant-thermocapillary convection in a rectangular vessel is experimentally studied for the 100cSt silicone oil with a large temperature-dependent Prandtl number (Pr=909 at 25°C). Utilizing the PIV and IRT techniques, the two-dimensional velocity fields in the mid-plane and the free surface temperature field are investigated. We have established the relationship between the total kinetic energy in the mid-plane and the imposed temperature difference for the first time through experiments. The well known return flow has been achieved and the first transition is observed from unicellular- to bicellular- flow at a much higher critical temperature difference relying on the layer depth. The transition conditions have also been transformed into a series of nondimensional parameters and mapped in the Ma-Bod and Ra-Bod spaces.

Through lab test, effect of improvement of high liquid limit clay by mixing of sand, Portland cement, quicklime and white lime were studied. Results show that compared with untreated soil, maximum dry density of high liquid limit clay improved by sand increase with the increase of mix-ratio of sand while optimum moisture content is decrease, but CBR value, swelling increment and soakage (after being immersed in water) of high liquid limit clay improved by sand change very little. Mixing of Portland cement can greatly increase CBR value of high liquid limit clay, and also lower swelling increment and soakage, but effect on optimum moisture content is very small and maximum dry density is only slightly increased. Mixing of lime can increase both optimum moisture content and CBR value of high liquid limit clay, and lower swelling increment and soakage at the same time. Through comprehensive comparison of effect of mixing of sand, Portland cement, quicklime and white lime on lowering moisture content of high liquid limit clay and effect on its optimum moisture content, CBR, swelling capacity, and soakage, mixing of quicklime has the best effect of improvement of high liquid limit clay.

A two-DoF (degree of freedom) motion model was established for a mechanical pectoral fin. The secondary development of FLUENT (CFD code) software, which is based on the Reynolds-Averaged Navier-Stokes equations (RANS) was adopted. The methods of dynamic mesh and post-processing system of FLUNET were also fully used. The hydrodynamic performances of mechanical pectoral fin in viscous flows were calculated and the calculating results were compared with the latest experimental results. The influences of kinetic parameters on the pectoral fin hydrodynamics were analyzed, which was a basis for the later physical experiments.

The experimental research of flow past obstacles is conducted by particle image velocimetry (PIV) system. A special apparatus has been designed and developed Three types of obstacles are used in the study are three types, which are quadrate cylinder, trapeziform cylinder and triangular cylinder. The obstacles are placed adjacent with a slope. The mean velocity distribution of the whole field is obtained under the Reynolds number of 3700. The streamlines of mean velocity field in the symmetry plane are given. The vortices characteristics of flow past various obstacles are described in detail. Visualization results indicate that the position and size of vortices in the wake are quite different. The vortex position of quadrate cylinder is lowest, triangular cylinder highest and trapeziform cylinder. All of them are lower than those when obstacles are placed on horizontal plane. From model A to model C, the size of vortices becomes larger. It can be explained that the shape of obstacles and the slope both have effect on the size and position of vortices. Based on experimental data, the mean streamwise and spanwise velocity components of each obstacle are plotted at specified streamwise stations. Finally the reattachment length of three models is calculated. The data obtained from this work are available for computational results to compare with in the future.

Pure liquid-liquid diffusion driven by concentration gradients is hard to study in normal gravity environments because of the contributing of convection and sedimentation to the mass transfer process. The paper presents the influence of gravity to mass transfer in diffusion process using an experimental technique based on optical digital interferometry for measuring mass transfer coefficients. The diffusion experiments are monitored by a March-Zehnder interferometer which can record all mass distribution information. Such information is not only available at the steady state, but within the whole diffusion process. The time-dependent evolution of the concentration field allows the measurement of diffusion coefficient. The measurements of transport coefficients have been performed in water/glucose mixture. The experiment apparatus are also set up for TF-1 rocket which can get the results in microgravity environment. So the significant influence of gravity can be demonstrated obviously.

Gas-solid two-phase flow experiments of fly ash were carried out with compressed air being adopted as dynamic force in the long-distance pipeline. Groups of GP/DP transmitters were installed along the pipeline. The solids velocity was expressed by the distance versus time interval of pressure signal of the two transmitters. Thus the trends of particle velocity and pressure drop along the pipe were given experimentally and theoretically. Meanwhile, according to experimental data, resistance properties along the pipeline were performed experimentally and transport mechanism in dense-phase pneumatic conveying was analyzed. Based on dynamic balance of gas-solid two-phase flow, associated with experimental data, pressure drop calculation equation of horizontal pipe in dense-phase pneumatic conveying was established.

It is crucial to investigate the capillary driven flows along interior corners because of the interior corners of space fluid management devices provide the main conduits for the transfer of fluids. In many instances, the interior corners are not perfectly sharp but rather possess a degree of roundedness due to the design or fabrication. In this work, the problem of capillary flows along rounded interior corners is revisited experimentally. Four test cells which are made of PMMA are designed. The cross sections of the four cells are the same pentagon except that one 90° corners are rounded with different radius R0 (sharp corner), R2.4, R4.8, R6, respectively. Four kinds of liquids are used in the microgravity drop tower tests, i.e. KF96-5 silicone oil, KF96-10, KF96-50 and Fluorinert liquid FC-70. The experimental results show that the advancing meniscus tip location of the fluid in the corner L (mm) is affected by container geometry and fluid properties. These experimental results are valuable to better understand the capillary flow and also can provide scientific guidance for the design and analysis of space fluid management systems.

Several studies of jets impinging on a plane surface have already been made. This paper presents the results of effect of convex curvature on the mean flow characteristics of wall jets. Measurements were performed up to an axial distance of 60 times the slot widths of the orifice selected in the present work. The flow properties considered in the present paper are the mean velocity profiles, maximum velocity decay and the growth of half width. Comparisons have been made with the two-dimensional wall jet. It is observed that the longitudinal mean velocity profiles exhibit similarity for the convex wall jet when compare to plane wall jet. All the mean velocity profiles are self-similar at all the longitudinal distances measured in the present study. It is shown that the decay of the maximum velocity is higher for a three-dimensional wall jet on convex surface compare to plane wall jet. It is also found that the growth of half width is higher on curved surface when compared to plane wall jet.

The effects of non-resonant flow case, including supercritical case and subcritical case, on the nonlinear surface waves of film with uneven bottom were analyzed. Derived from the potential flow theory, the fKdV equation on the nonlinear surface wave was obtained by the little parameter perturbation technique. The simulation was made by pseudo-spectral method, and the waterfall plot of the surface wave was illustrated with Matlab program. The flow, incompressible and inviscid, of which the surface tension and uneven boundary is considered. The results comprehensive surface waves located on the film when the flow case is non-resonant one is different from the resonant case.

This article discusses in detail the principle of drag-reducing using the grooved surface. The flow boundary layer over five kinds of different shapes grooved surface are studied experimentally by PIV technology, obtained velocity distribution at flow direction and normal direction. used the loss method of flow momentum and Ludwieg & Tillman experience formula method, respectively, calculated the local drag coefficient of groove and smooth plate and make a detailed comparative analysis. Investigated the factors on the impact of resistance of influence groove resistance properties, and analysis the mechanism of drag reduction, Show that groove has the function of weakened the role of turbulence, and this implies that the local friction of the flow is reduced. The maximum drag reduction efficiency in the 2^# groove plate is the drag reduction 5.89 %. The experimental results indicate that using the PIV technology to measure the turbulent boundary layer is totally feasible.

Vortex generator jets (VGJs) have been recognized as an effective active control method for the flow separation. To investigate its mechanism in conical diffuser, PIV was used to study the interaction of VGJs with freestream in this study. A conical diffuser model, with divergence angle of 14° was used. The jet holes were drilled with pitch angle of 30° and skew angle of 90°. At several streamwise locations, two-dimensional traverses were set up to obtain the velocity distribution and vorticity in the interaction region of vortex. PIV measurements provide a global depiction of the interaction of boundary layer transition and separation in this unsteady environment. It is shown that vortical flows generated by VGJs significantly fluctuate velocity profiles. The steady jets create vortices that swept the low momentum fluid up from the boundary layer while transporting high momentum freestream fluid towards the wall, which provides the ingredients for flow control. It is also revealed that the longitudinal vortices are generated in the boundary layer by shear stress and friction from jets, which increase cross-stream mixing of streamwise momentum and then suppress separation in conical diffuser. Some new phenomena and rules presented would offer valuable information for further study.

Water hammer phenomena of two-phase bubbly flow caused by a rapid valve closure in a 90° bend pipe were investigated experimentally. The experiments were conducted in a horizontal tube of 25.4mm in inner diameter and 1.9~3.8 in ratio of the curvature radius to the inner diameter of the bend tube, in the ranges of superficial velocity from 0.23 to 1.64 m/s and of void fraction from 0. 0% to 1.12%. The air and water were used as the working fluid. The value of potential surge and its attenuation, and propagation velocity of the compression waves were obtained and discussed, comparing them with those in the single-phase water flow. The distribution of potential surge in a 90° bend pipe is a "ring", and it was respect with void fraction, superficial velocity, curvature radius.

This paper describes a new technique for presenting information based on given flow images. Using a multistep first order differentiation technique, we are able to map in two dimensions, vorticity of fluid within a region of investigation. We can then present the distribution of this property in space by means of a color intensity map. In particular, the state of fluid rotation can be displayed using maps of vorticity flow values. The framework that is implemented can also be used to quantify the vortices using statistical properties which can be derived from such vorticity flow maps. To test our methodology, we have devised artificial vortical flow fields using an analytical formulation of a single vortex. Reliability of vorticity measurement from our results shows that the size of flow vector sampling and noise in flow field affect the generation of vorticity maps. Based on histograms of these maps, we are able to establish an optimised configuration that computes vorticity fields to approximate the ideal vortex statistically. The novel concept outlined in this study can be used to reduce fluctuations of noise in a vorticity calculation based on imperfect flow information without excessive loss of its features, and thereby improves the effectiveness of flow

The suitability of hybridizing measured strain (from commercial strain gages) and photoelastic (from birefringent coatings) information with a stress function and numerical tools for full-field stress analyzing engineering problems is emphasized. Applications include those to traction-free and pin-loaded holes in isotropic aluminum plates, orthotropic composites and wood. For the pinned joints, both pin/hole clearance and friction are accounted for, and the stresses on the contacting edge of the loaded hole are determined.

The conventional phase shifting technique requires a specific number of phase shifting steps (e.g., 3, 4, or 5) with known phase shifting intervals (e.g., π/2 or 2π/3). However, the error of phase shifting amounts in real applications is common due to various reasons, and such error can cause substantial error in the determination of phase distributions. This practical and important problem can be well coped with by the random phase shifting technique. Unlike the conventional techniques, the random phase shifting technique is capable of accurately extracting phase distributions from any arbitrarily phase-shifted interferograms or fringe patterns. With the advanced technique, not only the number of phase shifting steps but also the phase shifting intervals/amounts can be completely random as long as at least three frames have different phase shifts. In this paper, the theory of the random phase shifting technique is reviewed and selected applications are demonstrated.

Recently the authors developed sampling moiré method which analyzes the phase distribution of one image of a moiré fringe pattern. The captured image is analyzed by performing easy image processing, i.e., thinning-out and linear interpolation, to obtain the multiple phase-shifted moiré patterns. Then, the phase distribution of the moiré pattern can be calculated using phase-shifting technique. The accuracy of the phase analysis is high because the phase is analyzed with a phase-shifting method. The accuracy is checked using simulation and experiment by changing several factors. An application of the sampling moiré method applied to deflection measurement of a metal cantilever beam is performed. The average error of the deflection measurement is less than 1/500 of the grating pitch.

We show in this paper that regularized phase tracking and windowed Fourier ridges algorithms in fringe pattern analysis and digital image correlation, though seem to be very different, are actually similar and can even be expressed in a unified optimization framework.

In this paper, an automated phase unwrapping algorithm for isoclinic parameter based on the phase stepping technique is presented. It provides whole-field maps of isoclinics for both σ1 and σ2 directions. The technique is based on processing four photoelastic fringe images of stressed photoelastic model acquired using a dark-field plane polariscope. The unwrapping process starts with the (largest) region selected on the basis of a threshold value and a map of isoclinics required. It works with two models (circular disk and ring under diametral compression), regardless of the presence of the isotropic points. The obtained results from the application reveal that the algorithm provides reliable experimental maps of σ1 and σ2 directions which are comparable to those maps obtained from simulated fringes.

The keys to realize the on-line measurement of revolving body's profile based on the digital image measuring method are the calculation accuracy and speed of the sub-pixel edge detection algorithm. In this paper, several kinds of sub-pixel edge detection algorithms are studied. Based on this study, a new sub-pixel edge detection algorithm named mixed algorithm is developed. The experimental results confirm that the new algorithm is stable and reliable. It can not only advance the calculating speed, but also extend the accuracy of position to better than 0.01pixels.

A new approach was proposed for detecting and segmenting the beacons from low contrast infrared image captured from two CCD detectors fixed on two sides of deck, respectively. Adaptive thresholding is used for obtaining binary image of the infrared beacons by rough segmentation in preprocessing step, which probably contains some non-beacons areas. Then line encoding is conducted for binary image containing beacons and non-beacons, which is a look-up table (LUT) with little data quantity. Refined beacons extraction and recognition based on various features are conducted within LUT data. Finally, the geometric features (e.g. rectangularity, circularity, eccentricity) combining with the moment invariants is used to recognize the real beacons by minimum euclidean distance and prior information of artificial beacon. Experimental results show that the proposed method can preserve the perfect shape of beacons and effectively detect and track it for opto-electronic guiding system.

Isoclinic parameter is one of the important parameters in (digital) photoelasticity. This paper presents a comparative study of two phase unwrapping methods for the parameter. The two phase unwrapping methods are a line-wise method and a semi-region-wise method. The paper focuses on the way that how the methods handle the wrapped isoclinic map(s), which is used to start unwrapping, having the edge-cut line and non-edge-cut line in the final or unwrapped isoclinic map. The edge-cut line and non-edge-cut line are the line of isoclinic jumps that link the points of discontinuity (isotropic points) with some points locating at the boundaries and inside the isoclinic map, respectively. For the evaluation, three models, the circular disk and ring under diametral compression and circular disk under three radial loads, were used. The comparative results show that the semi region-wise method is superior to the line wise method.

An innovative broken-ray videometrics method is proposed to resolve the problem of long time monitoring of rocks' deformation in underground tunnel structures. For the deformation measurement of underground projects, the traditional measurement techniques using level gauge or theodolite can only measure one dimensional displacement. Although videometrics methods have been applied in many fields, there are often not intervisible optical paths between the positions to be measured in the underground projects. The broken-ray videometrics method we proposed can measure the orientation and position between the reference and non-intervisible target due to the intricate structure of tunnels. Broken-ray path is constructed by relay-stations between the control points on the ground and underground point to be measured. Finally, laboratory experiments were designed which showed satisfactory accuracy.

The existence of zero-order image has certain effect on the quality of reconstructed images in off-axis digital holography. For eliminating the zero-order image in off-axis digital holography, a method of zero-order image elimination in off-axis digital holography by using of FIR (Finite Impulse Response) filter is proposed in this paper. This method is based on digital image processing. First, by analyzing the spatial spectrum characteristic of off-axis digital hologram and the principle of using FIR filter to eliminate zero-order image, the paper theoretically proved that the zero-order image can be effectively eliminated by the FIR filter method before reconstruction. Then, the digital simulation and experiment recorded holograms were processed in the program with the FIR filter method and reconstruction. Both the theoretical analysis and digital reconstruct results show that it can effectively eliminate the large bright spot in the center of the reconstructed image which caused by zero-order image, and improve the image quality significantly, give better contrast of the reconstructed image. This method is very simple and convenient for free of phase modulator or any extra optical element and needing only one time record.

Fringe patterns produced by electronic speckle pattern interferometry (ESPI) are evaluated to measure the deformation on object surfaces. Noise is one of the key problems affecting further processing of the fringe patterns and reduces the final measurement quality. This paper presents a partial differential equations (PDEs) based coherence enhancing denoising model to reduce the noise, enhance the flow-like structure and improve the image quality of fringe patterns. Experimental results show that this filter is flexible and capable of removing most of the noise in ESPI fringe patterns.

It is proved that super-cooled large droplets (SLD) impingement onto airfoil have a great effect on aircraft icing. In the research facility of icing wind tunnel at Cranfield University in U.K, a great number of droplet splashing images are captured from aircraft icing experiments in order to understand the process of SLD impacting onto airfoil surfaces. Meanwhile, it also aims to classify the airfoil samples into wet/dry surface to determinate what material of samples is suitable for ice protection onto the aircraft. This paper defines a multi-dimensional feature space to characterize the images as criteria of classification. By k-means algorithm, images can be categorized into dry surface, wet surface, and ambiguous groups. Based on the results of image classification, eight of nine samples succeed to be identified into wet/dry behavior. However, one sample fell to the false identification since the raw images are insufficient to represent the entire droplets splash impact events.

A micro-structure construction method for reservoir rock is developed based on the CT and digital image processing techniques. 3D pore structure of the dolomite rock and 3D pore throat model are constructed. Based on the constructed models, the pore throat length and average diameters are statistically analyzed.

In order to get whole shape of an object, lots of parts of 3D images need to be captured from multiple views and aligned into a same 3D coordinate. That usually involves in both complex software process and expensive hardware system. In this paper, a shortcut approach is proposed to align 3D images captured from multiple views. Employing only a calibrated turntable, a single-view 3D camera can capture a sequence of 3D images of an object from different view angle one by one, then align them quickly and automatically. The alignment doesn't need any help from the operator. It can achieve good performances such as high accuracy, robust, rapidly capturing and low cost. The turntable calibration can be easily implemented by the single-view 3D camera. Fixed with the turntable, single-view 3D camera can calibrate the revolving-axis of the turntable just by measuring the positions of a little calibration-ball revolving with the turntable at several angles. Then system can get the coordinate transformation formula between multiple views of different revolving angle by a LMS algorithm. The formulae for calibration and alignment are given with the precision analysis. Experiments were performed and showed effective result to recover 3D objects.

In order to learn the microstructure mechanics property of lime solidify soil, the digital image tracking technology has been introduced and used to track the soil particles, based on the micro-images captured by the long work distance telecentric microscope lens. On one hand, the sample of lime solidify soil is made into cylinder specimen. One of the half-parts is taken as the experimental specimen. Then, the region plane observed in the middle of soil specimen is compartmentalized nine small regions. One of the small regions is the tracking objective. When the objective is tracked successfully, the images of nine regions under the same loads are captured. On the other hand, using the transformed correlation formula, the tracking speed is improved. Moreover, According to the characteristic of soil under loads, the objective is successfully tracked by selecting the rectangle template and rectangle search region. Finally, using the image processing method, the evolution regulations of the porosity of soil sample under uniaxial stress are obtained. That is, the porosity is increased with the rising stress. In conclusion, the microstructure characteristic of lime solidify soil is agree with the macro property of lime solidify soil.

This paper dedicates to study how to construct a perfect high resolution image from images with few different in-focus locals. Multi-focus technology which grabs images focused on different region in the same scene to rebuild a whole-focus image is adopted to perform this work. However, integrating with the advantages of so many images is a considerable difficult task. In view of this, the paper presents an algorithm for fast realization with high precision. Firstly, a batch of reversible two-dimensional FIR filters is designed to extract useful components from the local focused images. Based on comprehensive consideration, an efficient calculation flow is presented too. Secondly, a detector (PPE, point property evaluation) based on gradient energy is designed to evaluate point property of each channel divided by the FIR filters. According to the evaluation, the components in each channel are synthesized to build corresponding target channel. Finally, a perfect image can be obtained by adding all the target channels. At last, the algorithm is verified by an actual application. In this test, one perfect image is reconstructed from 9 local focalized images photographed with telephoto lens. Besides, other intermediate experiment results also provide support to the ideas adopted in the algorithm.

Computed tomography (CT) is one of the most important tools in the diagnosis of thoracic tumors. However, during the scanning process, respiratory motion causes changes in the position and shape of the tumor, creating motion artifacts in the CT scan. This can lead to misdiagnosis of the size and position of the tumor, and can affect the effectiveness of treatment. This study develops a computer model of the movement of the thorax, and simulates the movement of a lung tumor caused by breathing during a CT scan. We show that adjusting the CT slice thickness is sufficient to determine the center of displacement and maximum displacement of a tumor during normal breathing. This model can be applied in the clinical diagnostic use of CT equipment. It will assist in finding the position of lung tumors from motion artifacts in CT scans. The target margin for treatment can thus be defined more accurately, so that appropriate doses of radiation can be applied to the target area, and irradiation of healthy tissue avoided.

The analysis of the phase distortion in fringe projection with phase shifting is described. A phase distortion is induced when phase shifting method is applied to extract the phase values from the projected fringe patterns in surface contouring. The phase distortion will affect the measurement results especially with measurement of micro-components. The cause of phase distortion is analyzed and its influence on the measurement of micro-component is discussed. In order to remove the phase distortion, a Windowed Fourier Transform (WFT) is employed to extract the phase information from contour measurement. The advantage of WFT phase extraction over the conventional phase shifting method is that WFT can overcome the phase distortion in phase extraction. The principle of the proposed WFT phase extraction method is described and experiment is conducted to measure the surface profile of a micro-component. It is shown that by the use of WFT phase extraction method the phase distortion induced in the conventional phase-shifting technique can be completely eliminated.

In real-time image processing, a large amount of data is needed to be processed at a very high speed. Considering the problems faced in real-time image processing, a distributed multiprocessor system is proposed in this paper. In the design of the distributed multiprocessor system, processing tasks are allocated to various processes, which are bound to different CPUs. Several designs are discussed, and making full use of every process is very important to system's excellent performance. Furthermore, the problems of realization fasten on the inter-process communication, the synchronization, and the stability. System analysis and performance tests both show that the distributed multiprocessor system is able to improve system's performance variously, including the delay, the throughput rate, the stability, the scalability. And the system can be expanded easy at aspects of software and hardware. In a word, the distributed multiprocessor system designed for real-time image processing, based on distributed algorithms, not only improves system's performance variously, but also costs low and expands easy.

It is hard and expensive to increase the speed of data processing by just improving the capability of the hardware. This paper puts forward a platform of image transmission and reception among computers in the network in order to speed up the data processing under the limitation of the existing hardware conditions. The basic idea is that the transmitter divides an integrated data into several parts and sends each of them to different computers in the network. Then these parallel receivers process their own received data and send them to the same terminal computer which function is to put the renewed data together according to certain order so that the original data is processed just like one high-performance computer does. The capability is expanded by updating the data periodically and processing several data simultaneously without interfering each other. The work of calculating and processing is accomplished by those parallel computers while the transmitter and receiver have low burden so that they can fulfill other work. Performance results show that the data processing speed can be increased by this method and the more computers, the better the performance.

This paper describes a theoretical and experimental analysis on full-filed stress distribution from thermoelastic measurements and its application to determination of stress concentration. The sum of the principle stress can be measured by TSA. The IR Lock in Thermography has been applied to measure the structure stress distribution by its high thermal resolving. In this study, the thermoelastic effect model is developed to study the relationship between the temperature and the applied stress in an elastic material. The FEM is used to study the thermodynamic effect with classical thermoelastic equation, and the valid condition is obtained that the adiabatic loading conditions prevail. The applied loading frequency directly effect on the adiabatic loading conditions for given elastic material. The experiment was carried out with carbon steel structure with a hole for various loading frequency by Lock in thermography. The experimental results show the stress distribution can be measure and a factor is obtained to measure stress in the non-adiabatic conditions (Low loading frequency). It was found that the structure stress can be evaluated with good accuracies by the lock in thermography.

This scientific paper presents two approaches, based on the thermographic technique, for fatigue assessment and stress measurement. The first method, based on the lock-in thermography, is an energy approach; it takes intrinsic dissipation as the fatigue indicator, and evaluates the fatigue limit through a drastic change in the rate of dissipated energy. The second method is the Thermographic Method, which takes temperature increment as the fatigue indicator to assess the fatigue limit of materials and mechanical components. The Energy Approach of the Thermographic Method is based on the energy expression of linear fatigue cumulative damage hypothesis and allows the rapid assessment of the whole S-N curve. This research paper advances this quantitative thermographic method for residual fatigue life assessment. A stress analysis technique, known as SPATE (Stress Pattern Analysis by Thermal Emissions), measures the temperature variation due to the thermoelastic effect for stress determination, which could be unfaithful when the stress level is relatively high. Thus we proposed to use the Thermographic Method to assess the cyclic stress amplitude σ_a through the S-N curve. Good predictions were achieved using all the methods.

This study focuses on a signal processing method of damage detection for concrete beams. On the surface of the concrete beam, two sensors are respectively used to excite/receive stress wave signals and catch the reflection information from the damages inside. In order to improve the signal to noise ratio, wavelet method is adopted to pre-process the raw signals. Afterwards, the pre-processed signals are interpreted by a prestack migration technique, which is the reverse problem of the wave propagation, and lead to the profile image of the concrete beam. Results show that with the help of wavelet de-noising method, the prestack migration method can display the locations and dimensions of the damages very well. It is also shown that the present method is more suitable for the incline damage than the horizontal stacking method. Moreover, by comparing the results with different sensor intervals, we analyzed the relatives between the sensor intervals and the resolutions of the profile imaging.

Back analysis is an effective method to obtain the rock mass mechanical parameters with measured displacements. But the traditional back analysis methods have some shortcomings, such as narrow scope of application and instability. The intelligent back analysis method which incorporates a neural network and a genetic algorithm can overcome the drawbacks mentioned above and give satisfactory results. In this paper, based on orthogonal design, neural network and genetic algorithms, the intelligent displacement back analysis was carried out for the excavation of an underground powerhouse of a pumped storage power station in China. First, a series of samples were selected to train the neural network so that the relations between displacement of rock mass and parameters were erected. Then the optimum values of parameters were gotten taking advantage of optimization of genetic algorithms. Substituting the obtained parameters into FDM software for forward computation, it was found that the calculated displacements agreed the measured data well. The intelligent back analysis method can be used as a powerful tool to find out the optimum mechanical parameters of rock mass.

There are many practical applications that involve the lateral impact problem on the beam with discontinuities. This paper focuses on the identification method for the lateral impact force history of the beam with discontinuities, which belongs to the inverse problem. A new method to detect the lateral impact force on the beam with discontinuities is developed. We use Green's functions to get the convolution relation between two kinds of impact forces and responses. A singular matrix equation for solving impact-force is obtained finally. The singular value dissolved method is employed to search for the lateral impact force. The simulation test is used to proof the validity of identification method developed. The modifiable Timoshenko beam equation is used to model response on the beam with discontinuities by impact-force. The method of characteristics is used for numerical solution of Timoshenko beam equations. A computer program for both forward and inverse problems is developed. A discontinuities beam model with clamped and free boundary condition is used to verify above method. The lateral impact force is identified. The very satisfactory agreement between the known and identified force histories shows that the identified method developed in this paper is reliable for impact force determination purposes. The force history by response with noise is detected and good results of identified impact force are obtained.

A inverse algorithm of rainbow detection was presented that permits one to get simultaneously the refractive index and size of droplet under low Signal-to-Noise Ratio (SNR) condition. The noise was removed based on Empirical Mode Decomposition (EMD) and feature points extraction technique. The parameters inversed according to a new built mathematic model and Debye theory. A numerical test and an experiment were taken to validate the algorithm. It is showed that the method greatly improves the accuracy of parameter inversion.

An experimental study of geometric characteristic identification of impacted object is presented by recording the stress waves inside the impacting projectile and then the effect of the geometric characteristics on the stress wave curves is analyzed. The discussions based on experimental results indicate that the geometric characteristics of the impacted object can be identified from the stress wave curves recorded by the gauges attached on the projectile surface.

In this paper, an efficient technique is proposed for identifying the impact forces acting on circular arch, which overcome the deficiency of ill-conditioned frequency response function (FRF) in the frequency domain approach. First the comparison of the force identifications based on Pseudo-Wavelet Deconvolution Method (PWDM) and Frequency Deconvolution Method (FDM) is introduced. Next, the excitation and structural response needed in PWDM are derived from experiment and simulation separately. Last, force reconstructions via PWDM with the simulated and measured arch structural responses are compared with the corresponding experimental input force. By virtue of this technique, the solution of this inverse problem for identifying the impact force becomes stable and accurate. Deficiently, some experience is needed in deciding the pulse width and the shift of wavelet force.

Reliability-Based Topology Optimization (RBTO) based on the Evolutionary Structural Optimization (ESO) using Reliability Index Approach (RIA) is developed. When the uncertainties such as the elastic modulus, applied load and dimensional variation exist in design process, the optimum topology obtained from the Deterministic Topology Optimization (DTO) can not satisfy the design constraints since it is obtained without consideration of uncertainties related to the random variables. To alleviate the possible degradation of performance in design process, these uncertainties must be considered during the process of topology or design optimization. In the case that the RBTO is used, it is possible to perform the topology optimization where the uncertainties of the random variables should be considered since RBTO can deal with the probabilistic constraints in topology optimization. Reliability Index Approach (RIA) and Performance Measure Approach (PMA) calculate the reliability index as a measure of the probability of failure. In this study, the RIA, which has the probabilistic constraints that are formulated in terms of the reliability index, is adopted to evaluate the probabilistic constraints. In the RBTO based on ESO, the sensitivity number is defined as the change of the reliability index due to the removal of the each element.

In this work, a white light interferometry technique has been developed for non-destructive testing of micro-components. Essentially, the method utilizes a white light source which illuminates a test object using a modified Michelson interferometer configuration. The test object is mounted on a piezoelectric transducer (PZT) moving stage with a resolution of 1 nm. Images of the test objects are recorded using a CCD camera and stored in a PC for subsequent processing. Tests are conducted on an etched micro-beam which contains un-etched residual remains and optical multifibre ends. The results obtained show good agreement with those obtained from existing commercial profilometers and atomic force microscope.

Instrumentation for testing of mechanical properties on the micro and nano scales has developed enormously in recent years. This has enabled the mechanical behavior of surfaces, thin films, and micro/nano components to be studied with unprecedentedly small scale and high accuracy. In this paper, several testing systems and techniques for studying micromechanical properties are reviewed with particular emphasis on the probe based platform and its applications. Topics include the principles and performances of the integrated systems between the probe and the micromanipulator, the piezo-stage, the optical and high resolution scanning microscopes, the single and dual probe testing systems and the related method of micro force test. Researches on the capillary interaction between the probe tip and air-water surface, the motion of graphite microflakes, and accurate measurement of the mechanical parameter of nanowire are provided.

High Pressure Torsion (HPT) is an effective way to diminish the size of the crystal particles and improve the mechanical performance of metal material. In this study, the micro-hardness, size of crystal particles and shear strain of copper samples treated with HPT and their relationship were investigated. The results showed that the micro-hardness of the HPT copper increases from 50 to 140 when the nominal shear strain increases from 0 to 5. Then it reached saturation state and the micro-hardness didn't increase obviously when the shear strain increased further. The grain size becomes smaller as the distance away from the centre of sample for the sample with fewer turns of torsion. For the sample with more turns of torsion, in addition to the grain size refinement, the micro-hardness reaches saturation and its spatial distribution is uniform both along thickness and radius direction.

The Value for material elastic modulus obtained from the indentation loading and unloading history of 45 carbon steel was compared to the value for 45 carbon steel elastic modulus tested by conventional tensile tester. The result indicates that the former was larger than the latter, increasing about 11.5%. The indenting process has been discussed along with a cone of semi-apical angle, α, with a spherical cap of radius, R. As a result, it is clear that the determination of the indentation contact depth h_c tested in the measure process is very important factor to calculate elastic modulus of the materials. It is shown that the effects of the pile-up or sink-in factors on the test data are obvious for the micro/submicro scale, especially for the nano scale. Therefore the reliability of data using indentation test should be noted.

An evaluation technique, which digital speckle image correlation method (DSCM) for displacement measure on the surface of the tested object pressed by an indenter, is proposed for the first time in this paper. The size effect in micro-indentation is discussed in detail based on calculating surface plastic deformation modes around indentation by DSCM, comparing hardness measured using three micro-indentation apparatus, and simulating piling-up and sinking-in of 45 carbon steel around conical indentation in finite element. We draw a conclusion that the indentation size effect relates to these factors such as load, test method, geometrical similarity of indentations, geometrical form of indenter tip as well as friction between indenter tip and surface of tested object. The finite element simulation result for 45 carbon steel revealed that the sinking-in occurs at the edge of imprints after unloading, no matter how the magnitude of the load is. In fact, the result obtained based on calculating surface plastic deformation modes around indentation by DSCM indicates that the property of deformation relates to load. When the load decreases from 1 N to 0.5 N, the surface deformation mode around indentation changes along with the load, contrary to the present research which neglects the load when considering deformation around indentation in finite element simulation. DSCM provides the technical support for probing into the essence of the indentation size effects.

Ultrasonic shot peening treatment is used to treat structural surfaces, which can enhance the overall strength, stiffness and fatigue life of the treated material. This process induces a layer of nanocrystal grains in the surface of austenitic stainless steel. The microstructure and the composition of the surface layer are examined using X-ray diffraction and transmission electron microscopy. Experimental results show that the grains are mainly composed of oxide nanocrystal particles, NiFe₂O₄, and a few martensite particles. Phase transformations happen during the course of the ultrasonic shot peening. The chemical composition of the nano-layer is (8.03 Cr, 4.32 Ni, 3.86 Cu, 83.79 Fe) (mass %).

The fabrication of magnesium alloy metal-matrix composites (MMCs) and the mechanical properties of the sandwich formed with this material were investigated. Magnesium alloy composites containing various volume percentage of 0.99, 2.91, 4.76 and 9.09 % silicon-carbide (SiC) particles were prepared by molten metal mixing and machined as the faceplate of the sandwich. The particle had been dispersed by the injecting of the argon gas from a stainless pipe. Optical microscopic examination, hardness and tensile test were carried out. The sandwich was combined by the hot press method and studied by bending test. It is observed that the hardness of MMCs increases, but its strength decreases with increasing volume percentage of silicon-carbide particle, according to the results of hardness and bending test. It can be found that the specific strength and specific bending strength of sandwich composites fabricated with the faceplates of magnesium alloy added SiC reinforcements are a little higher than that sandwich with the aluminum alloy faceplates, but less than that of sandwich with magnesium alloy.

Natural fiber polymer composites have various potential applications because of its particular property. In this paper, the template technique is employed to prepare SiO₂/kapok fiber composite and the mechanical properties of the kapok fibril and its composite are presented. The mechanical tests are carried out on a probe platform which consists of a micro probe with a sharp tip, a micro-force sensor, and a micromanipulator and operates under an optical microscope. The probe platform has a high accurate load and displacement resolutions that are able to meet the requirements of the measurements. During the tests, the probe is controlled by the manipulator to exert lateral force at the midpoint of the kapok fibers which is clamed as a tension spring on a frame. The force is detected by the force sensor and consecutive deformation images of kapok and SiO₂/kapok fibers are acquired by the optical microscopic systems. From consistently fitting the measured deformation profiles follows the more accurate calculation model. Thus, the mechanical properties, such as the load-displacement (stress-strain) curve, the elastic modulus of the kapok and SiO₂/kapok fibers under different gripping conditions are obtained.

With the trend of miniaturization of the tested objects, the coupling effect in micro/nano mechanical test among the measurement system, the sample and the test environment becomes an important issue. In this paper, a single cantilever typed probe system is proposed and the coupling effect between the loading probe and the tested samples are investigated. The deformations of the loading probe and the cantilever typed samples, Si and silicon nitride cantilevers, are measured with the experiments and their deformation behaviors are discussed.

Hole is one of the most common damages in the material. It is necessary to take the interaction among holes into consideration in the research of damage process of materials. The digital real-time holographic measurement system developed by us is used to measure the out-of-plane displacement of PMMA plates containing holes in this paper. The elastic field for the region which contains multiple holes is different from that of the region with one hole. The variation of elastic field due to the existence of multiple holes demonstrates the interaction among holes. It can be seen from the hologram recorded by the digital real-time holography that the distribution of elastic field is related to the configuration, the orientation and the distance of holes. Both the shielding effect and the amplification effect can be easily observed with the help of the distribution of fringes in hologram. These experimental results testify the credibility of the conclusions proposed by theory and by numerical computation.

Using the rock meso-mechanics experimental system provided by Key Laboratory of Rock and Soil Mechanics, Institute of Rock and Soil Mechanics, China Academy of Sciences, Wuhan, A series of uniaxial compression tests were performed to analyze the fracturing process and deformation characteristics of cement mixed soil. The meso-fracturing process of cement mixed soil was real-time observed using the microscope and the digital color camera. The stress-strain curves and the corresponding micro-images of specimens in failure process were obtained at the same time. The results are of great scientific references to setting up the mechanical model of the cement mixed soil effectively.

Micro cantilevers in atomic force microscopy are important force sensors in nano research, and the Young's modulus is one of the most important parameters of the cantilevers. Normal testing methods are not suitable for the Young's modulus detecting of micro cantilevers according to the strict scale of the cantilevers, and new methods are needed to the study of micro cantilevers. A new method for determination of Young's modulus of micro cantilevers based on combining the numerical simulation and frequency measurements is presented in this article. The new method involves three steps, the first step is developing the vibration model of the micro cantilever studied immersed in air; the second step is analyzing the vibration behavior of the corresponding cantilevers with the same geometry but different Young's modulus. The third step is measuring the resonate frequencies of the micro cantilevers immersed in viscous fluid such as air, and comparing the experimental results with the numerical results to determine the Young's modulus of the cantilever. Experiments on a commercial rectangular cantilever have been done to validate the method presented in this article.

The mechanical properties and surface shapes of the composited polyurethane coatings were tested by nanoindentation. Treated by high-temperature ageing and solarization, the composited polyurethane coatings were tested to investigate the different changes between the upper and the lower surfaces. The results show that the mechanical properties of the upper and the lower surfaces of the composited polyurethane coating hardly changed although it had been yellowing after 168 hours solarization ageing. But both the modulus and hardness of the upper and lower surfaces increased after 168 hours ageing at 75°C, especially for the lower polyurethane surface.

A new car in operation of only 8,000 km, because of malfunction, resulting in lost control and rammed into the edge of the road, and then the basic vehicle scrapped. According to the investigation of the site, it was found that the tie-rod of the car had been broken. For the subjective analysis of the accident and identifying the true causes of rupture of the tierod, a series of studies, from the angle of theory to experiment on the bended broken tie-rod, were conducted. The mechanical model was established; the stability of the defective tie-rod was simulated based on ANSYS software. Meanwhile, the process of the accident was simulated considering the effect of destabilization of different vehicle speed and direction of the impact. Simultaneously, macro graphic test, chemical composition analysis, microstructure analysis and SEM analysis of the fracture were implemented. The results showed that: 1) the toughness of the tie-rod is at a normal level, but there is some previous flaws. One quarter of the fracture surface has been cracked before the accident. However, there is no relationship between the flaw and this incident. The direct cause is the dynamic instability leading to the large deformation of impact loading. 2) The declining safety factor of the tie-rod greatly due to the previous flaws; the result of numerical simulation shows that previous flaw is the vital factor of structure instability, on the basis of the comparison of critical loads of the accident tie-rod and normal. The critical load can decrease by 51.3% when the initial defect increases 19.54% on the cross-sectional area, which meets the Theory of Koiter.

In this paper, the mechanical and thermal properties of compressed thin film titanium films with 150nm thickness deposited on an organic glass substrate under mechanical and thermal loads were measured and characterized. In order to simulate the thin films in IT which subjected compound loads and to produce the buckle modes, the external uniaxial compression and thermal loading are subjected to the specimen by the symmetric loading device and the electrical resistance film in this experiment. The temperature of the thin film deposited on substrate was measured using thermoelectric couple. The range of temperature accords with the temperature range of the MEMS. It is found that the size and number of the delamination and buckling of the film are depended upon the pre-fixed mechanical loading. The transient conduction and thermal stability of the film and substrate was studied with finite element method.

This paper demonstrates the wet etching effects on machined surface of single crystal Si. The machined surface was prepared by irradiating sample with low energy (~ 2keV) ECR sourced Ar⁺ ion beam. Then we performed etching process by HF(2.4%) at 20min,40min and 60min respectively. We analyzed surface of sample (before and after etching) by AFM and white light interferometer to measure surface roughness and machined depth. Finally we compared the etching effects on machining depth and surface roughness and result shows HF etching has remarkable effect i.e. increases both machining depth and surface roughness. Result also confirmed that etching effect can be controlled by etching time.

Recent advances in the electronics industries are drove by the rapid development of LCD technology. However, warpage is one of the major reliability and quality concerns in chip-on-glass (COG) packaging. Optical technique combined with microscopes is an obvious candidate for the non-contact measurement of warpage of LCD chips whose profiles vary from nanometers to micrometers. In this paper, projection speckle correlation method and Newton's ring interferometry are employed to obtain the warpage of a LCD chip. With respect to projection speckle correlation method, the technique of image merging is necessary in registration of 3D shape of entire object. Continuous wavelet transform is employed to extract 3D profile of the electronic chip by analyzing its fringe patterns. Phase retrieval is performed by computing the phase at a wavelet ridge. In addition, the points which introduce phase ambiguity are identified by tracking the inflexion points on the unwrapped phase map and detected by Savitzky-Golay differential operator. The feasibility of the proposed method is also validated by simulations. Experimental results from both techniques are compared, and excellent agreement is found. Above conclusions demonstrate that the techniques proposed in this study are powerful inspection tools for measuring warpage of LCD chips.

We use molecular dynamical software Material Studio^TM to investigate Young's moduli of Silicon nanowires along [001], [110] and [111] directions. Young's moduli for various directional and sized specimens are obtained via the energy-strain curves. The study suggests that the Young's modulus decreases as the thickness of the specimen decreases especially for the [001] direction, which display the peculiarity of anisotropy and size dependence. In comparison with the bulk silicon, the overall nanowires become soften for all the three directions. With respect to the results reported, similar trend is observed but magnitude of Young's modulus is not the same with each other. We analyze the dependence of Young's modulus on the size, surface structure and boundary conditions.

The main function of backlight modules (BLMs) of thin film transistor liquid crystal displays (TFT-LCDs) is to provide steady and intensive illumination for the whole monitor. Warpage of BLMs can produce non-uniform brightness in TFT-LCDs and result in the so-called Mura effect. In this paper, a warpage inspection system of BLMs was assembled. Experiment was designed to simulate the real working conditions of temperature and humidity, i.e. hygrothermal working conditions, of BLMs. Phase-shifting technique was adopted to improve the resolution of shadow moiré fringes. The surface morphology under different working conditions of BLMs was then obtained and plotted. The out-of-plane displacement fields of BLMs under the same working conditions was also analyzed by the commercially available finite element software ANSYS and compared with the experimental results. Finally, thermal stress distribution of BLMs can be calculated from the modified ANSYS model.

The aim of this work is to use non-destructive optical measurement techniques for defect detection. This paper presents the application of electronic shearography speckle pattern interferometry (ESSPI) to detect visible and invisible on the surface defects of a pine wood specimen The different artificial defects were created under the pine wood surface to simulate "defected" samples. The ESSPI set-up based on a He-Ne CW laser has been developed and used for studying the possible locations, sizes and shapes of wood defects. The results were real time and well agreed with the actual defects. Therefore the present method is feasible.

This paper describes a feasibility study of digital holographic interferometry for the measurement of curvature and twist of a deformed object. Measurement of curvature and twist is an important aspect in experimental mechanics. Numerous methods have been proposed to determine the curvature and twist by using digital shearography. We proposed a novel method to determine curvature and twist based on digital holography (DH) and complex phasor (CP). In the conventional methods, phase difference between the first and second states is obtained directly by digital phase subtraction (DPS) and Fourier transform is then employed to extract phase maps. In this study, CP method is proposed to improve the quality of phase maps corresponding to second-order derivatives. Subsequently, sine/cosine transformation and short time Fourier transform (STFT) are employed to process the wrapped phase maps. An experiment is conducted on a clamped circular plate under a point load at centre. The experimental results show that the proposed method is valid and able to obtain high quality phase maps corresponding to curvature and twist of a deformed object.

The floor location effect in the damage detection process is discussed on a 3 storey frame, which is compared to a numerical simulated vertical cantilever beam to illustrate the results. It is concluded that the effect of the floor location is insignificant on the frequency trend while the damage ratio varying, and it is significant while the damage location varying. The effect of the floor location is less while the damage locates nearer the floor location. The basic trend still exists while the damage location varying in the further investigation, but it may be covered by the local waves in the general illustrations. It is considered that the effect would be more significant to the unsupervised methods.

The basic idea of a piezoelectric admittance (reciprocal of impedance) technique for structural health monitoring is presented in this paper. An experimental study on damage detection of a steel frame structure is operated by the use of the high-frequency piezoelectric admittance signals. In this experiment, three PZT active sensors are bonded to three different components around a joint of the steel frame separately, and the looseness of bolts is identified by monitoring the variations of piezoelectric admittance measurements. From the experimental results it is found that the PZT active sensors hold the ability to detect structural local damage, i.e. they are insensitive to the damage in far fields. Subsequently, two damage indexes, the covariance and the cross correlation coefficient between two real admittance data sets are defined respectively, by which the extent of damage of the frame structure is evaluated. It is found that the cross correlation coefficient index can correctly reflect the damage extent of the frame structure qualitatively in different frequency ranges, but the covariance index can not.

The friction of the seal faces is the most important phenomenon in working process of contacting mechanical seals. The friction factor f is a key parameter for expressing the friction regime of the seal faces, the frictional power, the wearing capacity, the friction heat productivity, the temperature distortion of the end face and the temperature of the end face. The relationship between the friction factor f and the friction regime of the end faces of contacting mechanical seals was discussed from a microscopic point of view. The friction factor is usually worked out by the friction torque which is measured in the test. In the computer aided testing device of the mechanical seal system, the experimental investigations on the basic performance of the B104a-70 contacting mechanical seal was carried out. The test results indicate that the bigger the spring pressure of B104a-70 contacting mechanical seal, the bigger the friction factor. When the spring pressure is less, the bigger the rotational speed, the bigger the friction factor. But when the spring pressure is equal to 0.0866 MPa, the friction factor is not almost influenced by the rotational speed. When the rotational speed and spring pressure are less, the medium pressure has a less influence on the friction factor. When the rotational speed or spring pressure is bigger, the bigger the medium pressure, the less the friction factor.

Fault tree analysis method was applied to quantitatively investigate the causes of the leakage failure of mechanical seals. It is pointed out that the change of the surface topography is the main reasons causing the leakage of mechanical seals under the condition of constant preloads. Based on the fractal geometry theory, the relationship between the surface topography and working time were investigated by experiments, and the effects of unit load acting on seal face on leakage path in a mechanical seal were analyzed. The model of predicting seal life of mechanical seals was established on the basis of the relationship between the surface topography and working time and allowable leakage. The seal life of 108 mechanical seal operating at the system of diesel fuel storage and transportation was predicted and the problem of the condition monitoring for the long-period operation of mechanical seal was discussed by this method. The research results indicate that the method of predicting seal life of mechanical seals is feasible, and also is foundation to make scheduled maintenance time and to achieve safe-reliability and low-cost operation for industrial devices.

Damage identification and fatigue crack inspection during the test is a key foundation for full-scale aircraft fatigue test. It is very important to determine the fatigue life and maintenance period of the aircraft structure. The paper presents a brief introduction about a practical engineering method on real-time non-destructive evaluation (NDE) of aircraft structures for full-scale fatigue test. The content covers damage identifying and fatigue crack monitoring, which is based on the acquisition data acquired simultaneity during the test. The approach of damage identifying and crack growth monitoring is proven to be suitable and practical for full scale fatigue test.

Novelly Nuclear Magnetic Resonance Imaging (NMRI) as an advanced non-damaged measurement technique was introduced into the experimental research of transport of CBM. The home-made triaxial osmoscope made up of nonmagnetic polycarbonate material was designed and developed. The home-made osmoscope which has coal sample placed into the magnetic bore of NMRI equipment, a series of NMRI experiments of coal sample were made including NMRI experiment of the natural coal sample, the NMRI permeability measure experiment of coal sample of saturation water, NMRI experiment of gas driving water and NMRI experiment of water driving gas. In the experiments, the rough coal sample and the pressed coal sample were chosen individually. The processes of the water seepage, gas driving water and water driving gas in the coal sample were real-time, directly, visually measured. The many experimental conclusions with the practical engineering value were achieved for example the leading edge of water driving has inconsistency, the existence of dominance driving pathway was tested and the way almost kept fixed and so on.

In this paper, a damage detection method for the fiber reinforced composite beam is studied by applying Gabor wavelet transform to the dispersive flexural wave analysis. The impact experiment of the pre-cracked beam is investigated. Since wave propagation in the composite beam is too complicated to obtain much information for damage detection, the Gabor wavelet is introduced into the experimental wave signals. From the wavelet results, the arrival times and the amplitudes of incident, crack-reflected and transmitted waves can be gained. At last, the crack location can be determined and the damage extent can be estimated from the crack-reflected wave.

The mutual transformation of Martensite and Austensite and propagation of their interface are studied with the fourbeam moire interferometry during the process of loading of polycrystalline NiTi shape memory alloys (SMA). The distribution of Austensite and Martensite and the extension nearby the interface is observed from the moire photographs when the specimen is transformed.

A new digital image method for measuring soil landslide displacement is presented in this paper. First, the principle of surface fitting method to determine the sub-pixel gray value is introduced. Second, the optical experimental system and the specimen used in this experiment are described in detail. Then, the soil micro-displacement field can be measured by obtaining the clear image sequence of soil micro-slide of an expansive soil sample under water load and searching the gray value in sub-pixels by digital image surface fitting technology. The results show that through the optical system, this nondestructive testing method can improve the measurement accuracy, and has a very good prospect of application in the study of soil landslide. After getting a great deal of useful data, the principal of the displacement in different times and in different locations under different water load can be obtained by drawing displacement curves, consequently the experimentation can provide useful data for disaster prevention and mitigation research and actual construction. In addition, if using a CCD with higher resolution and more effective record area, or using synthetic aperture technology to increase effective record area, the accuracy of the experiment are expected to be further enhanced.

Dynamic load testing (DLT) is a high strain test method for assessing pile performance. The shaft capacity of a driven PTC (prestressed tubular concrete) pile in marine soft ground will vary with time after installation. The DLT method has been successfully transferred to the testing of prestressed pipe piles in marine soft clay of Lianyungang area in China. DLT is investigated to determine the ultimate bearing capacity of single pile at different period after pile installation. The ultimate bearing capacity of single pile was founded to increase more than 70% during the inventing 3 months, which demonstrate the time effect of rigid pile bearing capacity in marine soft ground. Furthermore, the skin friction and axial force along the pile shaft are presented as well, which present the load transfer mechanism of pipe pile in soft clay. It shows the economy and efficiency of DLT method compared to static load testing method.

The method of non-contact measurement is applied to test the vibration of bent top. Firstly, vibration velocities at the bent top along light paths were measured with the PDV-100 at two different positions. And secondly, vibration velocities at the bent top along direction and vertical direction of the rail were calculated. Velocity spectrum is changed into displacement spectrum by the method of frequency-spectrum- transformation. Curve of the vibration displacement time history is obtained finally. This method is very useful for the case when testing instrument can not be arranged on the direction of vibration due to the restriction of site condition.

ESPI (Electronic Speckle Pattern Interferometry) technique combined with stroboscopic laser illumination can be used to measure 3D harmonic vibration on any components and structures. It is automatically synchronized with the vibration frequency of the measured component and shows the vibration amplitude at any frequency. If the frequency is one of the resonant frequencies of the component, the vibration amplitude distribution would be a mode shape of the vibrating component. To improve the design of the rotor blade on certain type of aero-engine, ESPI measurement system was applied to measure the vibration modes of a primary blade and a modified blade. As well, the vibration response and the strain distribution of the blades were measured. Compared the test data of the primary and modified blades, the modified design can effectively move the fault modal frequency out of the original resonant region and decrease the modal response and strain distribution. The test results verified that the rotor blade design modification was effective.

IR Lock in thermography is an active thermography technology based on thermal wave signal processing, especially, it has many advantages for nondestructive test of composite materials and compound structure application and has been applied on aerospace, automotive, mechanics and electric fields. In lock in thermography, given sufficient time for periodic heating, the surface temperature will evolve periodically in a sinusoidal pattern form the transient state to the steady state. In this paper, the principle of lock in thermography is introduced and the heat transferring process is analyzed by the sinusoidal variation heating flow transferred in materials by means of FEM method. In experiment, the modulating optical stimulation is applied to sample, and image sequences are collected by Jade MWIR 550 FPA IR camera. The digital filter algorithm which is Savitzky-Golay digital smoothness filters is used to remove the effects of high frequency noise. A phase image at the frequency of periodic heating can be calculated using a Fourier transform of the periodic heating frequency in transient state for defect detection. The IR lock in thermography processing software is developed by using of visual C++ programmed based image sequence collected. The experimental results show that the developed system reached up to high level of conventional steady state Lock in method.

In this paper, the non-destructive testing process of lock-in thermography to some typical defects cases, including the composite with holes or ribs on its back, or inside with multi layers, air holes or defect, is simulated on the basis of the finite element method by ANSYS software. The results are also validated using the infrared thermography system developed by Cedip company. According to different defects type, different methods are given. In addition, influences of loading time, testing frequency, data processing and curved face on the non-destructive testing are also discussed in this paper. The results show that the finite element method can simulate the non-destructive testing process of lock-in thermography well. So the finite element method has obviously instructive effect on the selection of experiment parameters as well as can improve the testing efficiency.

Harmonic wavelet had explicit functional expression, flexible time-frequency division, simple transforming algorithm and a finer frequency refinement function than the others wavelet. In this paper based on frequency distributing characteristic of nondestructive testing signal from rockbolt supporting system, the discrete harmonic wavelet transforming theory was used to get rid of the lower and higher frequency signal from the initial signal. Meanwhile, the reconstruction algorithm of harmonic wavelet was brought forward to gain the signal without the unnecessary bandwidth signals. Finally, a numerical signal and real signal which can demonstrate superiority of harmonic wavelet in filtering are presented, and the transforming result shows that it would make the system run more precise and stably in the detecting to the quality of rockbolt supporting system.

This paper aims at assessing of corrosion defects in standard petroleum pipelines by shearography method. Shearography reveals the stress-affected zone due to additional loading that can be realized by the laser speckle correlation on the inspected object. In this study, the artificial corrosion in pipeline is modeled by creating circular defects of different depths and sizes. An internal air pressure was exerted to the 7mm thick pipe wall. The results show that change of internal pressure is an effective means to reveal corrosion activity in the pipelines. The speckle correlation for corrosion of more than 3mm depth with ▵P≥0.24MPa can clearly be observed. For comparison, radiography technique is used to correlate the depth and size of the corrosion defects and finally to detect the location of the corrosion area.

Determination of damage location and severity are important for the arch structure. First, the frequency perturbation formulate in damage identification are derived combining matrix perturbation theory with finite element technology. Next, an experimental test was carried out to determine the first six frequencies in the intact and damage arch structure. Finally, the location and severity of structural damages can be detected based on the measured natural frequencies of damage structure. The result shows the frequency perturbation method is feasible to the structural damage detection for the only need of frequency-data, and can be applied to damage detection in the arch structure.

In this study, the vibration correlation technique was introduced to determine the buckling load of rectangular thin plates. It is theoretically shown that the natural frequency approaches zero when the applied compressive load approaches the buckling load of the plate. To avoid the effects of premature out-of-plane deformation, it is proposed in this study that the buckling load is to be identified using the natural frequencies of plates under tensile loading. A set of aluminum plates was tested for natural frequencies using an impact test method. Specimens with two types of boundary conditions, i.e., CCCC and CCCF, were included in the experiment. The square of the measured natural frequency was plotted against the applied load and extrapolated to determine the predicted buckling load. The buckling loads from vibration data compare closely with numerical solutions. The average percentage differences between the measured buckling loads and the numerical solutions are 1.24 % and -1.14 % for specimens with CCCC and CCCF boundary conditions, respectively. In conclusion, the buckling load of rectangular thin plates can be experimentally identified with acceptable accuracy using vibration data. This approach is very useful especially for structures with unknown or imperfect boundary conditions where analytical or numerical solutions to the problem are not available.