This PDF file contains the front matter associated with SPIE Proceedings Volume 7290, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing

In field of endoscopy, in order to overcome limitation in conventional endoscopy, capsule endoscope has been developed and has been recently applied in medical field in hospital. However, since capsule endoscope moves passively through GI tract by peristalsis, it is not able to control direction of head including camera. It is possible to miss symptoms of disease. Therefore, in this thesis, 2-Axis Tilting Actuator for Endoscope, based on Ionic Polymer Metal Composites (IPMC), is presented. In order to apply to capsule endoscope, the actuator material should satisfy a size, low energy consumption and low working voltage. Since IPMC is emerging material that exhibits a large bending deflection at low voltage, consume low energy and it can be fabricated in any size or any shape, IPMC are selected as an actuator. The system tilts camera module of endoscope to reduce invisible area of the intestines and a goal of tilting angle is selected to be an angle of 5 degrees for each axis. In order to control tiling angle, LQR controller and the full order observer is designed.

Shape memory alloy (SMA) actuation is becoming an increasingly viable technology for industrial applications as many of the technical issues that have limited its use are being addressed (speed of actuation, mechanical connections, performance degradation, quality control, etc.) while increasing production capacities drive costs to practical levels. Shape memory alloys are often selected because of their high energy density which can lead to compact actuators; however, wire forms with small cross-sectional diameters tend to be long (10 to 50 times the length of required stroke). Spooling the wire can be used for compact packaging, but as the spool diameter decreases performance losses and fatigue increase due to bending strains and stresses. This paper presents a simple, design-level model for spooled SMA wire actuators with linear motion outputs that includes the effects of friction and wire bending and accounts for the actuator geometry, applied load, and material friction and constitutive properties. The model was validated experimentally with respect to the ratio of mandrel to SMA wire diameter and agrees well in both form and magnitude with experiments. The resulting model provides the framework for the analysis and synthesis of spooled SMA wire actuators to guide the selection of design parameters with respect to the tradeoffs between performance and packaging.

Shape memory alloy (SMA) wire actuators are quickly becoming technologically ready for a wider range of commercial applications due both to their exceptional actuation performance and to recent advances in the manufacture of drawn SMA wire. Shape memory alloys are complex materials requiring a breadth and depth of knowledge to successfully implement in more demanding industrial applications, knowledge to which most engineers may not have been exposed. This paper proposes a modular design framework to aid engineers at any level of expertise to synthesize and analyze SMA wire actuators. The modularity of the framework allows for changes in design, architecture, and system topology and allows for easy adaptation to the rapid research advances in the knowledge and understanding of the response and robust use of SMA. The layered structure of the framework is detailed; differentiating the design tasks by function: modeling, evaluation, optimization, and design guidance. Each layer is modular within itself, and in particular, the modeling layer allows for a variety of views to suit the expertise of individual designers. A sample design tool built within the framework is presented for the synthesis of actuators composed of multiple straight SMA wires acting against linear loads, accompanied by a physical system demonstration. This example, while basic, demonstrates the general applicability and flexibility of the framework for aiding many types of users in a large variety of SMA wire actuation design problems.

[Smart Vehicle Workshop] This paper presents the development of active aluminum-matrix composites manufactured by Ultrasonic Additive Manufacturing (UAM), an emerging rapid prototyping process based on ultrasonic metal welding. Composites created through UAM experience process temperatures as low as 20°C, in contrast to current metal-matrix fabrication processes which require fusion of materials and hence reach temperatures of 500°C and above. UAM thus creates unprecedented opportunities to develop adaptive structures with seamlessly embedded smart materials and electronic components without degrading the properties that make embedding these materials and components attractive. This research focuses on three aspects of developing UAM Ni-Ti/Al composites which have not been accomplished before: (i) Characterization of the mechanical properties of the composite matrix; (ii) Investigation of Ni-Ti/Al composites as tunable stiffness materials and as strain sensors based on the shape memory effect; and (iii) Development of constitutive models for UAM Ni-Ti/Al composites. The mechanical characterization shows an increase in tensile strength of aluminum UAM builds over the parent material (Al 3003-H18), likely due to grain refinement caused by the UAM process. We demonstrate the ability to embed Ni-Ti wires up to 203 μm in diameter in an aluminum matrix, compared with only 100 μm in previous studies. The resulting Ni-Ti/Al UAM composites have cross sectional area ratios of up to 13.4% Ni-Ti. These composites exhibit a change in stiffness of 6% and a resistivity change of -3% when the Ni- Ti wires undergo martensite to austenite transformation. The Ni-Ti area ratios and associated strength of the shape memory effect are expected to increase as the UAM process becomes better understood and is perfected. The Brinson constitutive model for shape memory transformations is used to describe the stiffness and the strain sensing of Ni-Ti/Al composites in response to temperature changes.

This paper presents the design, theoretical analysis, microfabrication and testing of a new type of millimeter-size acoustic sensor using Polyvinylidene Fluoride (PVDF) micropillars and patterned electrodes. The sensor has the potential to achieve 100x the sensitivity of existing commercial sensors in combination with a sound pressure level (SPL) range of 35-180 dB and a frequency bandwidth of at least 100 kHz. A constrained optimization algorithm has been developed as a function of geometric parameters (sensor footprint, diameter and height of the micropillars, gap between pillar edges, and number of pillars) and electrical parameters of the sensor and conditioning amplifier. Details of the fabrication process are described. Nanoindentation tests demonstrate that the PVDF micropillar sensor exhibits piezoelectric responses under an applied voltage or strain, thus demonstrating the sensor concept. Operational amplifier circuit design and experimental setup are also described and developed.

Full suspension mountain bicycles exhibit unwanted suspension movement during pedalling. Damper manufacturers frequently adopt what is known as platform damping to overcome this problem. Such dampers resist low frequency pedalling inputs due to the presence of a threshold or 'platform' damping level. However, this platform compromises shock absorption ability over rougher terrain. In this paper, the authors describe a prototype rear shock absorber that utilises magnetorheological (MR) fluids to implement semi-active platform damping. Results from recent field trials will be presented, and the current status of commercialising the system will be discussed.

Airflow over/under/around a vehicle can affect many important aspects of vehicle performance including vehicle drag (and through this vehicle fuel economy), vehicle lift and downforce (and through these vehicle stability and handling), and cooling/heat exchange for the vehicle powertrain and air conditioning systems. Known devices in current use to control airflow over/under/around the vehicle are all of fixed geometry, location, orientation, and stiffness. Such devices can thus not be relocated, reoriented, reshaped, etc. as driving conditions change and thus airflow over/under/around the vehicle body cannot be adjusted to better suit the changed driving condition. Additionally, under-vehicle airflow control devices, such as air dams, also reduce ground clearance and thus present a constant challenge to designers to provide the needed control of airflow while maintaining sufficient ground clearance to avoid damage. The research project whose second phase is described herein had its genesis in brainstorming on ways in which the field activated shape and stiffness changing attributes of several classes of active materials could be utilized to produce on-demand deploying/stowing of an air dam. During this second phase, bench top working models were developed, constructed, and successfully exercised this demonstrating the feasibility of an SMA actuator based approach to reversibly deploying an air dam through bending of its flexible structure. Beyond feasibility, the bench top working models demonstrated an active materials based approach which would add little weight to the existing stationary system, and could potentially perform well in the harsh under vehicle environment due to a lack of bearings and pivots. This demonstration showed that actuation speed, force, and cyclic stability all could meet the application requirements.

A bidirectional magnetostrictive actuator with millimeter stroke and a blocked force of few tens of Newtons has been developed based on a Terfenol-D driver and a simple hydraulic magnification stage. The actuator is compared with an electrodynamic actuator used in active powertrain mounts in terms of electrical power consumption, frequency bandwidth, and spectral content of the response. The measurements show that the actuator has a flat free-displacement and blocked-force response up to 200 Hz, suggesting a significantly broader frequency bandwidth than commercial electromagnetic actuators while drawing comparable amounts of power.

The plug-in hybrid-electric vehicle (PHEV) concept allows for a moderate driving range in electric mode but uses an onboard range extender to capitalize on the high energy density of fuels using a combustion-based generator, typically using an internal combustion engine. An alternative being developed here is a combustion-based thermoelectric generator in order to develop systems technologies which capitalize on the high power density and inherent benefits of solid-state thermoelectric power generation. This thermoelectric power unit may find application in many military, industrial, and consumer applications including range extension for PHEVs. In this research, a baseline prototype was constructed using a novel multi-fuel atomizer with diesel fuel, a conventional thermoelectric heat exchange configuration, and a commercially available bismuth telluride module (maximum 225°C). This prototype successfully demonstrated the viability of diesel fuel for thermoelectric power generation, provided a baseline performance for evaluating future improvements, provided the mechanism to develop simulation and analysis tools and methods, and highlighted areas requiring development. The improvements in heat transfer efficiency using catalytic combustion were evaluated, the system was redesigned to operate at temperatures around 500 °C, and the performance of advanced high temperature thermoelectric modules was examined.

A distributed wireless sensor network is embedded inside car seats to enable the measurements of the weight of the occupants, location of their center of gravity, and spatial orientation of their bodies. Based on these measurements, intelligent decisions can be made to ensure their comfort and safety particularly in case of accidents. Appropriate activation of the inflatable bags according to the weight and position of the occupants will be critical to avoiding unnecessary and undesirable injuries.

The ability to control the effective friction coefficient between sliding surfaces is of particular fundamental and technological interest for automotive applications. It has been shown that the friction force between sliding surfaces can be reduced by superimposing ultrasonic vibrations on the macroscopic sliding velocity. We developed a systematic approach based on experiments and models to describe and characterize the friction force between sliding surfaces in the presence of ultrasonic vibrations generated by a piezoelectric transducer. The controlling parameters in this study are static contact pressure, relative velocity, voltage, and frequency. Using a low power PMN-PT driver, we experimentally demonstrate a decrease of up to 68 % in effective friction coefficient and analytically show the underlying principle behind the friction reduction. The trends show a decrease in the effect with increasing sliding velocity and normal load. The results underscore the role of ultrasonic power in harnessing the friction control concept in applications.

To perform in-situ measurements on Mars or other planetary bodies many instruments require powder produced using some sampling technique (drilling/coring) or sample processing technique (core crushing) to be placed in measurement cells. This usually requires filling a small sample cell using an inlet funnel. In order to minimize cross contamination with future samples and ensure the sample is transferred from the funnel to the test cell with minimal residual powder the funnel is shaken. The shaking assists gravity by fluidizing the powder and restoring flow of the material. In order to counter cross contamination or potential clogging due to settling during autonomous handling a piezoelectric shaking mechanism was designed for the deposition of sample fines in instrument inlet funnels. This device was designed to be lightweight, consume low power and demonstrated to be a resilient solid state actuator that can be mechanically and electrically tuned to shake the inlet funnel. In the final design configuration tested under nominal Mars Ambient conditions the funnel mechanism is driven by three symmetrically mounted piezoelectric flexure actuators that are out of the funnel support load path. The frequency of the actuation can be electrically controlled and monitored and mechanically tuned by the addition of tuning mass on the free end of the actuator. Unlike conventional electromagnetic motors these devices are solid state and can be designed with no macroscopically moving parts. This paper will discuss the design and testing results of these shaking mechanisms.

Traditional fastening systems exhibit various limitations that a next-generation shape memory polymer (SMP) system can overcome. Bolts and screws provide high-strength attachment but require permanent modification to the system and are typically visible, depending on the configuration. Adhesive bonding can provide high-strength attachment and low visibility, but it is irreversible. Hook and loop fasteners offer reversibility, but the fastened strength and the removal force are similar, limiting the applications. The unique properties of SMP enable a fastening system that offers advantages not currently available in any one fastening system, including reversibility, low visibility, and high-strength attachment. Cornerstone Research Group (CRG) designed a fastener system that consists of an array of SMP heads and stems that interlock. The high modulus of the SMP at room temperature provides rigid attachment, keeping the system interlocked. When activated above the glass transition temperature (T_g), the heads and stems become soft and flexible, reducing the force required during attachment and detachment of the system. The shape memory property of the SMP ensures all heads and stems return to their original position to allow proper alignment. The developed system provides shear and tensile strength in excess of 300 psi with tensile detachment requiring only 2 psi. The material selection, design, testing, and optimization of the SMP fastening system are discussed.

Shape memory polymers (SMPs) are polymers that can recover a large pre-deformed shape in response to environmental stimuli, such as temperatures, light, etc. For a thermally induced amorphous shape memory polymer, the pre-deformation and recovery of the shape require the material to traverse the glassy transition temperature T_g under constrained or free conditions. In this paper, effects of thermal rates to mechanical behaviors of SMP under constrained condition were investigated. The stress-temperature behavior demonstrates a faster stress decrease than thermal contraction during cooling and a characteristic stress overshoot during constrained reheating. These observations were explained by a one dimensional (1D) model that considers the non-equilibrium structure relaxation and viscoelastic behavior of the material.

Stiffness variation versus stimulation for a light activated shape memory polymer (LASMP) is predicted with a multiscale modeling approach. The multiscale model utilizes rotational isomeric state theory to build a polymer chain conformation, Johnson distributions to model the distances between crosslinks, junction constraints to model neighboring chain interactions, and Boltzmann statistical mechanics to relate the entropy of the chain to the macroscopic response. It is shown that a novel choice for the equation describing stress dependence on strain, capturing the polymer's departure from affine deformation, results in a stress strain curve with an expected shape. The fitting parameters characterizing the interaction with neighboring chains can also be phenomenologically fit to experimental data, yielding accurate modulus predictions. The result is a bottom up model accurately predicting the material response of the polymer with parameters that can be derived almost entirely from the molecular formula of the polymer, allowing sufficiently similar polymers to be modeled accurately, reducing the time, effort, and resources required in the development of new polymer systems.

Light-activated polymers are an exciting class of materials that respond mechanically when irradiated at particular wavelengths. Recent demonstrations include two novel polymers developed by Scott et al (2006) and Lendlein et al (2005). In these polymers, photochemistry alters the microstructure of the cross-linked polymer network, which is further translated as light-induced deformation and when properly used light-induced shape memory effect. In this work, we develop a model framework to simulate the photomechanical response of light-activated polymer systems. This framework breaks down the observed macroscopic photomechanical phenomenon into four coupled sets of underlying physics, which occur throughout the material during irradiation and mechanical deformation. In the context of this framework, a basic photomechanical phenomenon involves simultaneously modeling photophysics, photochemistry, chemomechanical coupling, and mechanical behavior. Furthermore, network alteration are accounted for through the parallel decomposition of the cross-linked network into two components, an original network and a photochemically altered network, which allows to capture the observed photomechanical behaviors demonstrated in these materials. One of the principal strengths of this model framework is its generality as it can be applied to light activated polymer systems with fundamentally different of photophysics, photochemistry, and chemomechanical behaviors simply by choosing different field equations for the four sets of physics specific to a material system.

Seamless skins for morphing vehicles have been demonstrated as feasible but establishing robust fastening methods for morphing skins is one of the next key challenges. Skin materials previously developed by Cornerstone Research Group and others include high-performance, reinforced elastomeric and shape memory polymer (SMP)-based composites. Recent focus has shifted to improving performance and increasing the technology readiness level of these materials. Cycling of recently demonstrated morphing skins has determined that an abrupt interface between rigid and soft materials leads to localized failure at the interface over time. In this paper, a fundamental understanding between skin material properties and transition zone design are combined with advanced modeling techniques. A thermal gradient methodology is simulated to predict performance benefits. Experimental testing and simulations demonstrated improvement in morphing component performance for a uniaxial case. This work continues to advance development to eliminate fastening as the weak link in morphing skin technology and provides tools for use in morphing structure design.

Cornerstone Research Group Inc. (CRG) has developed environmental exposure tracking (EET) sensors using shape memory polymer (SMP) to monitor the degradation of perishable items, such as munitions, medicines or foods, by measuring the cumulative exposure to temperature and moisture. SMPs are polymers whose qualities have been altered to give them dynamic shape "memory" properties. Under thermal or moisture stimuli, SMP exhibits a radical change from a rigid thermoset to a highly flexible, elastic state. The dynamic response of the SMP can be tailored to match the degradation profile of the perishable item. SMP-based EET sensors require no digital memory or internal power supply and provide the capability of inexpensive, long-term life cycle monitoring thermal and moisture exposure over time. In a Phase I and II SBIR effort with the Navy, CRG demonstrated the feasibility of SMP-based EET sensor with two material systems. These material systems required different activation stimuli, heat or water vapor pressure. CRG developed the ability to tailor these materials to customize the dynamic response to match various degradation profiles of munitions. CRG optimized and characterized the SMP formulations and sensor design configuration to develop a suite of data from which any degradation profile can be met. CRG's EET sensors are capable of monitoring temperatures from -30 °C to 260 °C. The prototypes monitor cumulative thermal exposure and provide real-time information in a visually readable or a remotely interrogated version. CRG is currently scaling up the manufacture of the sensors for munitions reliability applications with the Navy.

Research and development efforts at Cornerstone Research Group Inc. (CRG) have led to commercialization efforts on several projects where shape memory polymer (SMP) materials are being transitioned from laboratory development to manufacturing and production. During this process, quality-control efforts are of vital importance for successfully implementing smart materials technologies in commercial applications. Here, CRG reports quality-control procedures being developed for mass production of environmental exposure sensors. These measures include chemical analysis procedures for insuring resin quality at the front-end of the production line as well as back-end quality-assurance tests for production validation on the SMP product.

A new concept of a morphing wing based on shape memory polymer (SMP) and its reinforced composites is proposed in this paper. SMP used in this study is a thermoset styrene-based resin in contrast to normal thermoplastic SMP. During heating, the wing curled on the aircraft can be deployed, providing main lift for a morphing aircraft to realize the stable flight. Aerodynamic characteristics of the deployed morphing wing are calculated by using CFD software. The static deformation of the wing under the air loads is also analyzed by using the finite element method. The results show that the used SMP material can provide enough strength and stiffness for the application. Finally, preliminary testing is conducted to investigate the recovery performances of SMP and its reinforced composites. During the test, the deployment and the wind-resistant ability of the morphing wing are dramatically improved by adding reinforced phase to the SMP.

Adequate postural balance depends on the spatial and temporal integration of vestibular, visual, and somatosensory information. Especially, the musculoskeletal function (range of joint, flexibility of spine, muscular strength) is essential in maintaining the postural balance. Muscular strength training methods include the use of commercialized devices and repeatable resistance training tools (rubber band, ball, etc). These training systems cost high price and can't control of intensity. Thus we suggest a new training system which can adjust training intensity and indicate the center of pressure of a subject while the training was passively controlled by applying controlled electric current to the Magneto- Rheological damper. And we performed experimental studies on the muscular activities in the lower extremities during maintaining, moving and pushing exercises on an unstable platform with Magneto rheological dampers. A subject executed the maintaining, moving and pushing exercises which were displayed in a monitor. The electromyographic signals of the eight muscles in lower extremities were recorded and analyzed in the time and frequency domain: the muscles of interest were rectus femoris, biceps femoris, tensor fasciae latae, vastus lateralis, vastus medialis, gastrocnemius, tibialis anterior, and soleus. The experimental results showed the difference of muscular activities at the four moving exercises and the nine maintaining exercises. The rate of the increase in the muscular activities was affected by the condition of the unstable platform with MR dampers for the maintaining and moving exercises. The experimental results suggested the choice of different maintaining and moving exercises could selectively train different muscles with varying intensity. Furthermore, the findings also suggested the training using this system can improve the ability of postural balance.

Flight vehicles are often designed to function around a primary operating point such as an efficient cruise or a high maneuverability mode. Performance and efficiency deteriorate rapidly as the airplane moves towards other portions of the flight envelope. One solution to this quandary is to radically change the shape of the aircraft. This yields both improved efficiency and a larger flight envelope. This global shape change is an example of morphing aircraft . One concept of morphing is the span morphing wing in which the wingspan is varied to accommodate multiple flight regimes. This type of design allows for at least two discreet modes of the aircraft. The original configuration, in which the extensible portion of the wing is fully retracted, yields a high speed dash mode. Fully extending the wing provides the aircraft with a low speed mode tailored for fine tracking and loiter tasks. This paper discusses the design of a span morphing wing that permits a change in the aspect ratio while simultaneously supporting structural wing loads. The wing cross section is maintained by NACA 4412 rib sections . The span morphing wing was investigated in different configurations. The wing area and the aspect ratio of the span morphing wing increase as the wings pan increases. Computational aerodynamics are used to estimate the performance and dynamic characteristics of each wing shape of this span morphing wing as its wingspan is changed. Results show that in order to obtain the same lift, the conventional wing requires a larger angle of attach(AOA) than that of the span morphing wing.The lift of the span morphing wing increases as the wing span ,Mach number and AOA increases.

Thermographic nondestructive testing techniques have been receiving increasing attentions as one of the effective NDT techniques, because of its non-contact, remote sensing, time-saving, and cost-saving vision techniques. However, the defect detecting ability of this technique basically depends on environmental condition such as surrounding temperature, initial temperature of inspection target, emissivity and so on. Most of thermographic NDT engineers have been concerned about this problem, also. This paper proposes two reference specimens, aluminum alloy and stainless steel for evaluating detecting ability of photothermal thermography nondestructive inspection system. This paper will improve on the reliability of thermographic NDT technique.