This PDF file contains the front matter associated with SPIE Proceedings Volume 6930, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

We detail the joint concept generation and embodiment development by HRL and GMR&D of shape memory polymer (SMP) based reversible-on-demand attachments. In this initial study of active material enabled reversible-on-demand attachments, our primary focus was on hook-and-loop type fasteners. The approach followed, in broader context, was to incorporate an active material, defined as a material which changes a fundamental mechanical property upon exposure to an appropriate field, in at least one component of the hook-and-loop assembly, in this way allowing a field activated change in the stiffness (raising/lowering) and/or geometry (straightening of the hook) of the component and thus on-demand release of the attachment This paper describes the fabrication method and properties of one of the two principle classes of embodiments made during the development of the concept. This class of embodiments, which utilized thermally activated shape memory polymer materials, was shown to exhibit pull-off forces similar to conventional "non-active" hook-and-loop fasteners, and significantly, as desired, was reversible with a reduction in the pull-off force of a factor of ~100. This study was thus successful in demonstrating the feasibility of a thermally activated SMP based reversible-on-demand distributed attachment.

Shape memory alloy (SMA) based actuators have the potential to be lower mass, more compact, and more simplistic than conventional based actuators (electrical, hydraulic, etc); however, one of the key issues that plagues their broad use is packaging since long lengths of wire are often necessary to achieve reasonable actuation strokes. Spooling the wire around pulleys or mandrels is one approach to package the wire more compactly and is useful in customizing the footprint of the actuator to the available application space. There is currently a lack of predictive models for actuator designs with spooled packaging that account for the variation of stress and strain along the wire's length and the losses due to friction. A spooling model is a critical step toward the application of this technique to overcome the packaging limitations on SMA actuators. This paper presents the derivation of an analytical predictive model for rotary spooled SMA actuators that accounts for general geometric parameters (mandrel diameter, wire length, wire diameter, and wrap angle), SMA material characteristics, loss parameters (friction), and the external loading profile. An experimental study validated the model with good correlation and provided insight into the effects of load and wrap angle. Based upon the model and experimental results, the main limitation to this approach, binding, is discussed. The analytical model and experimental study presented in this paper provide a foundation to design future actuators and insight into the behavioral impact of this packaging technique.

Pedestrian protection has become an increasingly important aspect of automotive safety with new regulations taking effect around the world. Because it is increasingly difficult to meet these new regulations with traditional passive approaches, active lifts are being explored that increase the "crush zone" between the hood and rigid under-hood components as a means of mitigating the consequences of an impact with a non-occupant. Active lifts, however, are technically challenging because of the simultaneously high forces, stroke and quick timing resulting in most of the current devices being single use. This paper introduces the SMArt (Shape Memory Alloy ReseTable) Spring Lift, an automatically resetable and fully reusable device, which couples conventional standard compression springs to store the energy required for a hood lift, with Shape Memory Alloys actuators to achieve both an ultra high speed release of the spring and automatic reset of the system for multiple uses. Each of the four SMArt Device subsystems, lift, release, lower and reset/dissipate, are individually described. Two identical complete prototypes were fabricated and mounted at the rear corners of the hood, incorporated within a full-scale vehicle testbed at the SMARTT (Smart Material Advanced Research and Technology Transfer) lab at University of Michigan. Full operational cycle testing of a stationary vehicle in a laboratory setting confirms the ultrafast latch release, controlled lift profile, gravity lower to reposition the hood, and spring recompression via the ratchet engine successfully rearming the device for repeat cycles. While this is only a laboratory demonstration and extensive testing and development would be required for transition to a fielded product, this study does indicate that the SMArt Lift has promise as an alternative approach to pedestrian protection.

The rapid urbanization of the world has led to an increase in pedestrian involvement in automotive crashes, prompting some countries to establish pedestrian regulations. A promising approach to address pedestrian safety is the use of active lift devices to raise the hood upon detection of a pedestrian impact, thereby increasing the crush distance between the hood and vehicle hard points (i.e. engine). Current systems are generally not reusable or resettable and lack extrinsic effect compensation. The dual chamber SMArt (SMA ReseTtable) lift system presented in this paper is a fully automatically resettable system utilizing a stored energy approach with a pneumatic cylinder and a two stage ultrafast shape memory alloy (SMA) actuated valve. This active lift possesses the unique functionality to tailor lift performance and compensate for extrinsic effects such as changes in temperature, mass, and platform using cylinder pressure and exhaust valve opening timing profile as operating parameters. As a proof of concept, a dual chamber SMArt lift system was designed, fabricated, and installed in a vehicle hood bay testbed. Full cycle tests demonstrated the functions of lift, lower and reset within the proper timing. The effect of additional mass, was experimentally characterized and two insitu device parameters, pressure and valve profile, were investigated as means to mitigate these extrinsic effects. This experimental study indicates that the dual chamber SMArt lift device may be a feasible alternative for pedestrian protection with automatic reset/reusability along with capability to adapt in-situ to maintain performance within a narrow timing window by compensating for extrinsic effects.

In recent years, researchers have investigated the feasibility of utilizing piezoelectric-hydraulic pump based actuation systems for automotive transmission controls. This new concept could eventually reduce the complexity, weight, and fuel consumption of the current transmissions. In this research, we focus on how to utilize this new approach on the shift control of automatic transmissions (AT), which generally requires pressure profiling for friction elements during the operation. To illustrate the concept, we will consider the 1→ 2 up shift control using band brake friction elements. In order to perform the actuation force tracking for AT shift control, nonlinear force feedback control laws are designed based on the sliding mode theory for the given nonlinear system. This paper will describe the modeling of the band brake actuation system, the design of the nonlinear force feedback controller, and simulation and experimental results for demonstration of the new concept.

Environmental concerns coupled with the depletion of fuel sources has led to research on ethanol, fuel cells, and even generating electricity from vibrations. Much of the research in these areas is stalling due to expensive or environmentally contaminating processes, however recent breakthroughs in materials and production has created a surge in research on waste heat energy harvesting devices. The thermoelectric generators (TEGs) used in waste heat energy harvesting are governed by the Thermoelectric, or Seebeck, effect, generating electricity from a temperature gradient. Some research to date has featured platforms such as heavy duty diesel trucks, model airplanes, and automobiles, attempting to either eliminate heavy batteries or the alternator. A motorcycle is another platform that possesses some very promising characteristics for waste heat energy harvesting, mainly because the exhaust pipes are exposed to significant amounts of air flow. A 1995 Kawasaki Ninja 250R was used for these trials. The module used in these experiments, the Melcor HT3-12-30, produced an average of 0.4694 W from an average temperature gradient of 48.73 °C. The mathematical model created from the Thermoelectric effect equation and the mean Seebeck coefficient displayed by the module produced an average error from the experimental data of 1.75%. Although the module proved insufficient to practically eliminate the alternator on a standard motorcycle, the temperature data gathered as well as the examination of a simple, yet accurate, model represent significant steps in the process of creating a TEG capable of doing so.

Despite vast technological improvements, the traditional internal combustion powered vehicle still achieves only 25- 30% efficiency, with the remainder lost primarily as heat. While the load leveling offered by hybrid-electric vehicle technology helps to improve this overall efficiency, part of the efficiency gains are achieved by making new systems such as regenerative braking viable. In a similar fashion, thermoelectric (TE) energy recovery has long been considered for traditional vehicles with mixed results, but little has been done to consider thermoelectrics in the framework of the unique energy systems of hybrid vehicles. Systems that may not have been viable or even possible with traditional vehicles may offer improvements to system efficiency as well as emissions, vehicle durability, passenger comfort, and cost. This research describes a simulation developed for evaluating and optimizing thermoelectric energy recovery systems and results for four different system configurations. Two novel system configurations are presented which offer the potential for additional benefits such as emissions reduction that will soon be quantified. In addition, a test setup is presented which was constructed for the testing and validation of various thermoelectric recovery systems. Actual test performance was near the expected theoretical performance and supported the conclusions reached from the computer simulations.

To provide a practical design method for Magnetorheological fluid damper (MRFD), mechanical model is established for two-exserted-pole gap type (TEP-GT) MRFD and the relationship between damping force and internal sizes is given. The magnetic circuit is studied and the materials and structures of main components are discussed. A practical design method for TEP-GT MRFD is obtained and several key expressions are provided. A kind of TEP-GT MRFD for the cable-stayed vibration control system is designed and manufactured.

The paper reports the holistic development of an active piezo-based component concerning the mechanical design and the control. The active component is used for the reduction of torsional vibrations in a strut of a tripod parallel kinematic machine. By means of this new component the main drawback of the x, y, z-tripod structure can be eliminated. A calculation shows the compliance of the connection between actuators and the adjacent mechanical parts as the most sensitive point of the design. The characteristic values of the piezo actuator were transformed into the active component with the help of design factors. For reducing the structural vibrations a control laws is presented that changes the properties of the electro-mechanical structure, like damping or stiffness. This is possible by a feedback of motion signals, e.g. velocity. The described electro-mechanical model was used for the control design. Experiment results, which are finally presented, show a reduction of structural vibrations.

Smart composites are composite structures that possess sensory and actuating properties through embedded transducers. In engineering practice the embedded transducers are often lead zirconium titanate (PZT) wafers coated on both sides with sputtered nickel or silver electrodes, employing the direct and inverse piezoelectric effect to sense and actuate strain, respectively. Structural composites provide the fragile PZT wafers with needed protection for practical use. A robust electrical connection to each wafer side is the primary challenge, particularly when embedding multiple wafer layers. Previous efforts involved attaching single wire leads to the electrode surfaces, leading to wire breakage or wafer micro-cracking under the high-pressure composite cure. A new approach uses conductive wire mesh layers throughout the composite ply area. Such meshes are advantageous in both the manufacturing process and the performance of the finished product. Standard composite manufacturing techniques are used. Multiple layers of PZT wafers can be robustly embedded with each having its own electrical address. The resulting smart composite is entirely modular: each embedded transducer can be reconfigured on the fly to serve as bimorph or unimorph strain sensor or actuator. Uses include active and passive structural health monitoring device and part of a high-precision active vibration damping system.

Membrane structures are excellent candidates for many lightweight large space structures, which can be utilized to improve the performance and to reduce the cost of space exploration and earth observation missions. In-orbit thermal disturbance is the main cause of membrane wrinkling, which deteriorates membrane surface accuracy. In order to maintain surface accuracy in the time-varying environment, active flatness control is regarded as a very important technology. In order to properly design active flatness control system, understanding of the thermo-mechanical coupling and the effects of tensioning forces in reducing membrane wrinkling is required. Based on the von-Karman nonlinear plate theory, a theoretical framework is developed in this paper. An FE model for a square membrane is developed as an example for case studies. Using thin shell elements, this model is capable of predicting the amplitude of out-of-plane displacements. Using this model, the effect of thermal disturbance is studied, which qualitatively agrees with experimental observations. By varying corner loads in the numerical model, it is demonstrated that corner loads can efficiently reduce surface deviation caused by a center-located heat source. In order to study the effect of thermal disturbance locations, different temperature distributions are applied to the membrane. With these temperature distributions, different tension forces combinations are evaluated in terms of improving surface accuracy.

The Air Force Research Laboratory/Space Vehicles Directorate (AFRL/RV) is developing a satellite structural architecture in support of the Department of Defense's Operationally Responsive Space (ORS) initiative. Such a structural architecture must enable rapid Assembly, Integration, and Test (AI&T) of the satellite, accommodate multiple configurations (to include structural configurations, components, and payloads), and incorporate structurally integrated thermal management and electronics, while providing sufficient strength, stiffness, and alignment accuracy. The chosen approach will allow a wide range of satellite structures to be assembled from a relatively small set of structural components. This paper details the efforts of AFRL, and its contractors, to develop the technology necessary to realize these goals.

The interest in synthetic-jet actuators is elicited by their employment in fluid-control applications, including boundary-layer control, combustion control etc. These actuators are zero net-mass-flux devices, and generally consist of a diaphragm mounted to enclose a volume of fluid in a cavity. The diaphragm bends sinusoidally, and fluid is periodically absorbed into and ejected from the cavity through an orifice. The outflow entrains the fluid around it and establishes a mean jet flow at some distance from the source. Piezoceramic materials have been employed to drive the actuator diaphragm, especially when actuation frequencies are in excess of a few hundreds of hertz. The piezoceramic is glued directly to a silicon diaphragm. In combustion systems, improved turbulent mixing of air and fuel proper can significantly improve efficiency and reduce pollution. In boundary-layer separation control applications, synthetic-jets are used to improve aerodynamic performance by delaying separation and stall over the airfoil. The current work describes the modeling and design process of a piezoceramic-driven synthetic-jet actuator intended, amongst other applications, to improve the aerodynamic characteristics of a specific airfoil. A separate study consisting of numerical analyses performed with the aid of computational fluid dynamics (CFD) have been run to define the necessary performance parameters for the synthetic-jet actuator. The synthetic-jet actuator design task was achieved by running fluid-structure numerical analyses for various design parameters.

Wind Tunnel tests of a NiTinol based actuator have been conducted for the reconfigurable rotor blade program. The purpose of the test was to demonstrate the potential to improve rotorcraft performance by optimizing the configuration of major structures in flight. The actuator is integrated into the rotor blade as a structural element controlling blade twist. A three-blade scale rotor was tested in a Boeing wind tunnel. The tests validated actuator design and performance by demonstrating simultaneous blade twist and control of twist position over the entire test matrix. A description of system requirements and compromises associated with the actuator and its integration into the rotor blade are provided and discussed. Test results showed that the RRB actuators were able to successfully twist the blade, control the twist between one twist state and the other, and simultaneously control three rotor blades to change state within two seconds of each other despite unanticipated electrical noise in the system.

There is a growing demand in recent years for lightweight structures in aircraft systems from the viewpoints of energy and cost savings. The authors have continued development of the Highly Reliable Advanced Grid Structure (HRAGS) for aircraft structure. HRAGS is provided with health monitoring functions that make use of Fiber Bragg Grating (FBG) sensors in advanced grid structures. To apply HRAGS technology to aircraft structures, a full-scale demonstrator visualizing the actual aircraft structure needs to be built and evaluated so that the effectiveness of the technology can be validated. So the authors selected the wing tip as the candidate structural member and proceeded to design and build a demonstrator. A box-structure was adopted as the structure for the wing-tip demonstrator, and HRAGS panels were used as the skin panels on the upper and lower surfaces of the structure. The demonstrator was designed using about 600 FBG sensors using a panel size of 1 x 2 m. By using the demonstrator, damage detection functions of HRAGS system were verified analytically. The results of the design and evaluation of the demonstrator are reported here.

The quasi-steady aerodynamics model is coupled to a dynamic model of ornithopter flight. Previously, the combined model has been used to calculate forward flight trajectories, each a limit cycle in the vehicle's states. The limit cycle results from the periodic wing beat, producing a periodic force while on the cycle's trajectory. This was accomplished using a multiple shooting algorithm and numerical integration in MATLAB. An analysis of hover, a crucial element to vertical takeoff and landing in adverse conditions, follows. A method to calculate plausible wing flapping motions and control surface deflections for hover is developed, employing the above flight dynamics model. Once a hovering limit cycle trajectory is found, it can be linearized in discrete time and analyzed for stability (by calculating the trajectory's Floquet multipliers a type of discrete-time eigenvalue) are calculated. The dynamic mode shapes are discussed.

A type of piezoceramic composite actuator commonly known as Macro-Fiber-Composite (MFC) is used for actuation in a variable camber airfoil design. The study focuses on aerodynamic and kinematical modeling, and static response characterization under aerodynamic loads for three similar concepts. From a broader perspective, the study aims to understand the behavior of solid-state aerodynamic vectoring in high dynamic pressure air flow. Wind tunnel experiments and theoretical analysis is conducted on a 1.15% thick, 54 mm chord, and 108 mm span composite airfoil. The airfoil is fabricated from a fiberglass/epoxy composite material and actuated by six MFC actuators in a unimorph arrangement. Three support concepts are studied: 1) Airfoil hinged at its leading edge and at 50% chord; 2) Airfoil hinged at its leading edge the trailing edge; 3) Clamped-free airfoil. Wind tunnel results and XFOIL studies of the airfoil show comparable effectiveness to conventional actuation systems. Deformation of the airfoils due to pressure distribution is studied by finite element method. All concepts present adequate stiffness for flow speeds up to 30 m/s.

Use of Shape Memory Alloy (SMA) actuation technology is a candidate method for reducing weight and power requirements for inlet flow control actuators in prospective supersonic passenger aircraft. The high speed/high Mach operating points of such aircraft can also call for the use of High Temperature SMAs, with transition temperatures beyond those of typical binary NiTi alloys. This paper outlines a demonstration project that entailed both testing and assessment of newly developed NiTiPt HTSMAs, as well as their use in an actuation application representative of inlet configurations. The project featured benchtop testing of an HTSMA-actuated ramp model as well as experiments in a high speed wind tunnel at loads representative of supersonic conditions. The ability of the model to generate adequate force and actuation stroke for this application is encouraging evidence the feasibility of NiTiPt-based devices for inlet flow control.

Shape memory alloy (SMA) wires are used increasingly in place of traditional actuators because of their compactness, high work density, low cost, ruggedness, high force generation, and relatively large strains. One well known issue with SMA wires is degradation in performance as actuation cycles accumulate, with significant reductions observed as soon as only tens or hundreds of cycles; thus, manufacturers typically recommend very conservative limits on the operation regime. This paper introduces an alternative approach of cycling or "shaking down" SMA wires under controlled conditions prior to installation. This enables the designer to design to the stable post-shakedown specification of the wire to produce actuators with repeatable larger forcing capabilities. This paper presents a preliminary experimental study which explores the functional dependence of shakedown performance on loading and strain history. A methodology is developed by which an SMA wire can be thermally cycled under electrical heating and the performance characterized with a double-exponential empirical model fit which captures the steady state performance of the wire and the rate at which shakedown occurs. Several sets of experiments are conducted to explore the functional dependence of the shakedown performance varying the load applied (29 to 78N), the allowed strain (4 to 7%), and the form of the loading function (linear spring vs. constant). These experimental studies expose important shakedown parameters affecting SMA actuator performance and provide a first step towards creating detailed SMA wire shakedown protocols tailored to the application that will enable the design of higher performance, stable SMA actuators.

Shape memory alloy actuators, with their simple operation through heating, and high solid state strain and force output are ideally suited to a range of robust engineering applications within the oil & gas industry, such as down-well flow control valves. Because reservoir temperatures can reach up to 250°C for very deep wells, a range of alloys with high transition temperatures are required. For a specific 'single-shot' valve application, with an operational temperature requirement of 110°C, a robust shape memory alloy (SMA) actuator, capable of delivering a stroke of 2 mm with high force output (4 kN), was developed and tested from Nitinol alloy H (Ni:Ti ratio of 49.5%:50.5%). The inducement of mechanical stresses within nickel-titanium alloys can influence the transitional temperature range of the alloy. This characteristic was exploited to raise the martensitic-to-austenitic transition temperature (A_p) of the alloy from 90°C to 130°C, through the application of large compressive cold-working stresses (equivalent to 10% compressive strains). The actuator acted as an electrically-activated trigger within a hybrid SMA-hydraulic valve. Once activated the actuator releases a high pressure seal allowing stored hydraulic pressure to operate the main mechanism of the valve. The operation of the SMA actuator and complete valve assembly, inclusive of battery pack and control electronics to activate the SMA, was successfully tested within a test-well environment at depths up to 900 meters and under hydrostatic pressures of 7,500 psi (51 MPa). The reliability of the valve and the SMA actuator demonstrates the applicability of this technology to down-hole oil & gas applications.

In the work to be presented, vacuum plasma spray forming has been used as a process to deposit and consolidate prealloyed NiTi and NiTiPd powders into near net shape actuators. Testing showed that excellent shape memory behavior could be developed in the deposited materials and the investigation proved that VPS forming could be a means to directly form a wide range of shape memory alloy components. The results of DSC characterization and actual actuation test results will be presented demonstrating the behavior of a Nitinol 55 alloy and a higher transition temperature NiTiPd alloy in the form of torque tube actuators that could be used in aircraft and aerospace controls.

A significant reduction in noise and improved fuel consumption can be achieved by varying the area of a commercial jet engine's fan nozzle. A larger diameter at takeoff and approach can reduce jet velocity reducing noise. Adjusting the diameter in cruise, to account for varying Mach number, altitude, etc, can optimize fan loading and reduce fuel consumption. Boeing recently tested a scaled variable area jet nozzle capable of a 20% area change. Shape Memory Alloy actuators were used to position 12 interlocking panels at the nozzle exit. A closed loop control system was used to maintain a range of constant diameters with varying flow conditions and to vary the diameter under constant flow conditions. Acoustic data by side line microphones and flow field measurements at several cross-sections using PIV was collected at each condition. In this paper the variable area nozzle's design is described. The effect of the nozzle's diameter on its acoustic performance is presented for a range of Mach numbers and mass flow rates. Flow field data is shown including the effects of the joints between the interlocking panels.

Precision flow pumps have been widely studied over the last three decades. They have been applied in the areas of Biology, Pharmacy and Medicine in applications usually related to the dosage of medicine and chemical reagents. In addition, thermal management solutions for electronic devices have also been recently developed using these kinds of pumps offering better performance with low noise and low power consumption. In previous works was presented the working principle of a pump based on the use of a bimorph piezoelectric actuator inserted in a fluid channel to generate flow. This work presents a novel configuration of piezoelectric flow pumps using a bimorph piezoelectric actuator of different aspect ratio. Sensibility studies of the rectangular cross-sectional area channel are conducted computationally (CFD) and three parameters are investigated: resonance frequency and oscillation amplitude of the piezoelectric actuator, and pressure inside the channel. Also, experimental tests are conducted to verify the influence of clamps' rigidity and actuator's insulator. The experimental results show that improving these two aspects it is possible to achieve higher flow rates.

Precision flow pumps have been widely studied over the last three decades. They have been applied in the areas of Biology, Pharmacy and Medicine in applications usually related to the dosage of medicine and chemical reagents. In addition, thermal management solutions for electronic devices have also been recently developed using these kinds of pumps offering better performance with low noise and low power consumption. In a previous work, the working principle of a pump based on the use of bimorph piezoelectric actuators inserted in a fluid channel to generate flow was presented. The present work aims at the development of novel configurations of piezoelectric flow pumps based on the use of bimorph actuators with biomimetic tip geometries that are inspired in fish caudal fin shapes, such as ostraciiform, subcarangiform, carangiform and thunniform. The pump development consists in designing, manufacturing and experimental characterization steps. In the design step, computational models of pump configurations are built to perform sensitivity studies and to apply optimization techniques using ANSYS finite element analysis software. The prototype manufacturing is guided by the computational simulations. Electronic circuits for pump electrical excitation and control are developed and implemented. Comparisons among numerical and experimental results are also made.

The aim of the article is to introduce into usage of waveguide for the medical invasion treatment and to provide methods that allow investigating the vibrations of the stainless steel waveguide by combining non-contact techniques with the state-of-the-art multiphysics software. The vibrations of the waveguide, used in surgery are examined by the aids of the hybrid numerical-experimental techniques, acoustic emission method, holographic interferometry technique and vibrometer based on Doppler shift of backscattered laser light. The virtual modeling of the waveguide is used by the Comsol Multiphysics software.

This paper describes the development of a deformable mirror to be used in conjunction with diffractive optical elements inside a laser cavity. A prototype piezoelectric unimorph adaptive mirror was developed to correct for time dependent phase aberrations to the laser beam, such as those caused by thermal expansion of materials. The unimorph consists of a piezoelectric disc bonded to the back surface of a copper reflective mirror. The rear electrode of the piezoelectric ceramic disc is divided into segments so that a number of different control voltages can be applied to deform the mirror in a desired displacement distribution. The mirror is required to be able to deform in the shape of each of the lower order Zernike polynomials, which describe aberrations in optical systems. A numerical model of the device was used to determine a suitable electrode configuration. Finally, the device was constructed and the deformed shapes measured using a laser vibrometer.

Piezoelectric acoustic-electric power feed-through devices transfer electric power wirelessly through a solid wall using elastic waves. This approach allows for the elimination of the need for holes through structures for cabling or electrical feed-thrus . The technology supplies power to electric equipment inside sealed containers, vacuum or pressure vessels, etc where holes in the wall are prohibitive or may result in significant performance degradation or requires complex designs. In the our previous work, 100-W of electric power was transferred through a metal wall by a small, piezoelectric device with a simple-structure. To meet requirements of higher power applications, the feasibility to transfer kilowatts level power was investigated. Pre-stressed longitudinal piezoelectric feed-thru devices were analyzed by finite element modeling. An equivalent circuit model was developed to predict the characteristics of power transfer to different electric loads. Based on the analytical results, a prototype device was designed, fabricated and successfully demonstrated to transfer electric power at a level of 1-kW. Methods of minimizing plate wave excitation on the wall were also analyzed. Both model analysis and experimental results are presented in detail in this paper.

This paper describes a new class of flight control actuators using Post-Buckled Precompressed (PBP) piezoelectric elements mounted within a transonic missile fin. These actuators are designed to produce significantly higher deflection and force levels than conventional piezoelectric actuator elements. Classical laminate plate theory (CLPT) models are shown to work very well in capturing the behavior of the free, unloaded elements. A new high transverse deflection model which employs nonlinear structural relations is shown to successfully predict the performance of the PBP actuators as they are exposed to higher and higher levels of axial force, which induces post buckling deflections. A 6" (15.2cm) square rounded diamond transonic fin was made with integral PBP actuator elements. Quasi-static bench testing showed deflection levels in excess of ±7° at rates exceeding 21 Hz. The new solid state PBP actuator was shown to reduce the part count with respect to conventional servoactuators by an order of magnitude. Power consumption dropped from 24W to 1.3W, slop went from 1.6° to 0.02° and peak current draw went from 5A to 18mA. The PBP actuator was wind tunnel tested and shown to possess no flutter, divergence or adverse aeroelastic coupling characteristics.

One approach to morphing aircraft is to use bistable or multistable structures that have two or more stable equilibrium configurations to define a discrete set of shapes for the morphing structure. Moving between these stable states may be achieved using an actuation system or by aerodynamic loads. This paper considers three concepts for morphing aircraft based on multistable structures, namely a variable sweep wing, bistable blended winglets and a variable camber trailing edge. The philosophy behind these concepts is outlined, and simulated and experimental results are given.

A comparative study has been made to explore the potential benefits of newly available single-crystal ferroelectric materials when used in a practical device, in this case an ultrasonic micro-motor. This type of micro-motor exhibits exceptional power-to-weight characteristics, which could be exploited beneficially, for example, in unmanned air-vehicle (UAV) systems. The operating principles of a range of commercial and experimental motor designs were evaluated objectively in order to identify areas of performance that can potentially be enhanced using PMN-PT single-crystal piezoelectric ceramics. Based on this analysis a practical motor design was selected for construction and experimentation. Detailed numerical analysis indicated that a motor constructed from single crystal PMN-PT could be expected to provide an improvement in motor stall-torque by up to a factor of 2.8 and a no-load speed improvement by a factor of 1.5 when compared with motors based on standard polycrystalline lead-zirconate-titanate (PZT) ceramics. In practice single-crystal versions of the motor were found to produce double the power output of their polycrystalline counterparts. Overall efficiency was found to be improved two-fold. There were significant discrepancies between the numerical predictions for the single-crystal devices and their measured performance, whereas the polycrystalline devices were found to perform closely in line with predictions.

Over the past years, there are growing interests on scavenging energy from ambience for portable and low-power electronic devices. Among these low-power electronic devices, wireless sensor networks combined with piezoelectric power harvesting devices are the most promising scenario which using piezoelectric cantilever beam structure excited by ambient vibrations to convert mechanical vibration power to electric power and power the wireless sensors. It is known that the environmental excitation frequency will not be always the same as the resonant frequency of the cantilever beam. However, the cantilever beam excited under resonant frequency will have the highest energy output. In this paper, bimorph and sandwich type structure with frequency tuning circuit is proposed to shift the resonant frequency of the piezoelectric cantilever beam in real-time to match the environmental excitation frequency in order to increase the power efficiency and harvest more energy. For the bimorph and sandwich laminated PZT cantilever beam, there will be 2 layers and 3 layers of PZT layers, and one for the PZT layers will be used to control the beam resonant frequency by connecting to different electrical loading impedance. The exciting frequency will be monitored by a low-power micro-processor usually used on wireless sensors. The design and fabrication of the bimorph and sandwich beam structure with and without frequency tuning circuit will all be evaluated and detailed in this paper.

Advances in development of linkage integrated tubular actuators for gripping, wrapping, and general manipulation purposes are described in this paper. Analytical and FE models are presented. The mechanical architecture based on structural part called "elastic joint" is actuated inserting tubular elements. System embedding tubular actuators obtaining the "joint actuator" is described in the paper. The tube is a sealed tight system which prevents incoming pollution due to the actuation system. No leakage problems are issued, the actuator is suitable for common clean procedures which fit the standards in clean-room environment. The motion system investigated use only "pipe shaped actuators", avoiding the architectures with dynamic sealing. Investigated fluidic actuator is suitable for manipulation in clean room and it could be used in general purposes mechatronic systems as well.