This PDF file contains the front matter associated with SPIE Proceedings Volume 6527, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

The research field of smart materials and structures has been a distinct entity for two decades. Over the past ten years, the SPIE Industrial and Commercial Applications Conference has presented a Smart Structures Product Implementation Award at its annual symposium. This paper revisits the nine winning entries to date (1998-2007) and updates their status. The paper begins with a brief description of the original and current intent of the award and follows with a short overview of the evolution of smart structures, from research to products. The winning teams and their respective products are then described. The current status of the products is discussed based on publicly available information and input from the respective companies. Note however that it is not the purpose of the paper to rank the product winners in terms of success or sales. The paper concludes with an assessment of the larger trends in productization of smart structures technologies. The application "form" for the award as well as the evaluation criteria and suggestions for improving award application packages can be found in the appendix.

Precision satellite payloads commonly require isolation from bus disturbance sources, such as reaction wheels, thrusters, stepper motors, cryo-coolers, solar array drives, thermal popping, and other moving devices. Since nearly every satellite essentially has a unique construction, custom isolation systems are usually designed to attenuate a wide bandwidth of disturbance frequencies. The disadvantage of these custom solutions is that they are not easily reusable or transferable and are generally not robust to changes in payload geometry and mass properties during the development. The MVIS-II isolation system is designed to provide vibration disturbance attenuation over a wide bandwidth, as well as being able to adapt to changes in payload mass properties and geometry, through active control of a smart material. MVIS-II is a collaborative effort between the Air Force Research Laboratory (AFRL) Space Vehicle Directorate and Honeywell Defense and Space to validate miniature hybrid (passive/active) vibration isolation of sensitive optical payloads. The original flight experiment was intended to isolate a non-critical representative payload mass for demonstration purposes; however, the MVIS-II has been adapted to support the primary optical payload onboard the Tactical Satellite 2 (TacSat-2). Throughout the program MVIS-II has been able to adapt to changes in the payload geometry and mass properties with modification limited to support structures only. The MVIS-II system consists of a hexapod of hybrid struts, where each strut includes a patented passive 3-parameter DStrut n series with a novel hydraulically amplified piezoelectric actuator with integral load cell. Additionally, Honeywell's Flexible I/O controller electronics and software are used for command and control of the hardware. The passive D-Strut element provides a 40 dB/decade passive roll-off to attenuate mid-to-high frequency disturbances, while the active piezoelectric actuator is used for enhanced low frequency isolation. MVIS-II struts are 90% smaller in size and have 91% less mass than previous struts including Honeywell's Vibration Isolation, Suppression, and Steering (VISS). The MVIS-II system is currently integrated in the TacSat-2, which has successfully launched from Wallops Flight Facility on Wallops Island, Virginia in December 2006. MVIS-II was launched under direction of the DoD Space Test Program. This paper will discuss the adaptive design of the MVIS-II isolation system including simulation, testing, and integration. Active and passive strut test results will be presented that demonstrate the wide bandwidth attenuation of vibration disturbances. Simulation results of expected on-orbit performance will also be discussed.

Membrane structures are attracting attention as excellent candidates for lightweight large space structures, which can be utilized to improve the performance and reduce the cost of space exploration and earth observation missions. Membrane structures can be stowed to a small volume during launch and function as large structures after deployed. For many applications, maintaining surface accuracy of membranes is extremely important to achieve satisfactory performance, especially for membrane antennas and adaptive optics. Active flatness control is a vital technology to maintain surface accuracy of membrane structures. In this research, multiple shape memory alloy (SMA) actuators around the boundary of a rectangular membrane are used to apply tension forces to membrane structures to compensate wrinkle effects. The dynamics of membrane structures is nonlinear and computationally expensive, hence unfeasible to be used in real-time active flatness control. As a parallel direct searching method, genetic algorithm (GA) is used search optimal tension force combination on a high dimensional nonlinear surface. Due to increasing number of tension forces to search, the convergence is more difficult to attain. In order to increase responsiveness and convergence of genetic algorithm, an adaptive genetic algorithm (AGA) is proposed. Adaptive rules are incorporated in a modified genetic algorithm to regulate control parameters of genetic algorithm. Through numerical simulation and experimental studies, it is demonstrated that AGA can expedite its search process and prevent premature convergence.

Passive mechanical isolation is often times the first step taken to remedy vibration issues on-board a spacecraft. In many cases, this is done with a hexapod of axial members or struts to obtain the desired passive isolation in all six degrees-of-freedom (DOF). In some instances, where the disturbance sources are excessive or the payload is particularly sensitive to vibration, additional steps are taken to improve the performance beyond that of passive isolation. Additional performance or functionality can be obtained with the addition of active control, using a hexapod of hybrid (passive/active) elements at the interface between the payload and the bus. This paper describes Honeywell's Isolation, Pointing, and Suppression (IPS) system. It is a hybrid isolation system designed to isolate a sensitive spacecraft payload with very low passive resonant break frequencies while affording agile independent payload pointing, on-board payload disturbance rejection, and active isolation augmentation. This system is an extension of the work done on Honeywell's previous Vibration Isolation, Steering, and Suppression (VISS) flight experiment. Besides being designed for a different size payload than VISS, the IPS strut includes a dual-stage voice coil design for improved dynamic range as well as improved low-noise drive electronics. In addition, the IPS struts include integral load cells, gap sensors, and payloadside accelerometers for control and telemetry purposes. The associated system-level control architecture to accomplish these tasks is also new for this program as compared to VISS. A summary of the IPS system, including analysis and hardware design, build, and single axis bipod testing will be reviewed.

An actuation system, making use of paraffin wax as a smart material, has been developed for high force, large displacement applications. Wax actuators exploit the significant volumetric expansion (typically between 10 and 15%) experienced during the solid to liquid phase change of paraffin wax. When contained, this expansion results in considerable hydrostatic pressure. Traditionally, wax actuators are designed such that the wax acts directly, via a compliant seal, on an output device such as a piston. We propose using an additional intermediate (passive) fluid to transmit pressure to a separate remote actuator. In essence, we propose a solid-state 'pump' for hydraulic actuation, with no moving parts and which requires no maintenance. The pump makes use of paraffin wax pellets, submerged in hydraulic fluid. The pellets are encapsulated in silicone rubber to prevent contamination of the hydraulic fluid. Upon melting, the volumetric expansion is used to displace the hydraulic working fluid, which is in turn used to drive a conventional hydraulic actuator. Making use of only 65g of paraffin wax, heated from room temperature to 80ºC, the pump generated a blocked pressure of 45MPa and displaced 15.7ml of hydraulic fluid. The pump was used to drive a commercial actuator, and achieved a free stroke of 24.4mm and a blocked force of approximately 29kN.

Aerospace systems stand to benefit significantly from the advancement of reflexive aerostructure technologies for increased vehicle survivability. Cornerstone Research Group Inc. (CRG) is developing lightweight, healable composite systems for use as primary load-bearing aircraft components. The reflexive system is comprised of piezoelectric structural health monitoring systems, localized thermal activation systems, and lightweight, healable composite structures. The reflexive system is designed to mimic the involuntary human response to damage. Upon impact, the structural health monitoring system will identify the location and magnitude of the damage, sending a signal to a discrete thermal activation control system to resistively heat the shape memory polymer (SMP) matrix composite above activation temperature, resulting in localized shape recovery and healing of the damaged areas. CRG has demonstrated SMP composites that can recover 90 percent of flexural yield stress and modulus after postfailure healing. During the development, CRG has overcome issues of discrete activation, structural health monitoring integration, and healable resin systems. This paper will address the challenges associated with development of a reflexive aerostructure, including integration of structural health monitoring, discrete healing, and healable shape memory resin systems.

Composites are becoming increasingly popular materials used in a wide range of applications on large-scale structures such as windmill blades, rocket motor cases, and aircraft fuselage and wings. For these large structures, using composites greatly enhances the operation and performance of the application, but also introduces extraordinary inspection challenges that push the limits of traditional NDE in terms of time and cost. Recent advances in Structural Health Monitoring (SHM) technologies offer a promising solution to these inspection challenges. But efficient design methodologies and implementation procedures are needed to ensure the reliability and robustness of SHM technologies for use in real-world applications. This paper introduces the essential elements of the design and implementation process by way of example. State-of-the-art techniques to optimize sensor placement, perform self-diagnostics, compensate for environmental conditions, and generate probability of detection (POD) curves for any application are discussed. The techniques are presented in relation to Acellent's recently developed SmartComposite System that is used to monitor the integrity of large composite structures. The system builds on the active sensor network technology of Acellent that is analogous to a built-in acousto-ultrasonic NDE system. Key features of the system include new miniaturized lightweight hardware, self-diagnostics and adaptive algorithm to automatically compensate for damaged sensors, reliable damage detection under different environmental conditions, and generation of POD curves. This paper will provide an overview of the system and demonstrate its key features.

This paper investigates the applications of the piezoelectric acoustic sensors for real time detection of crack initiation and propagation in ceramic composites. In the first case this paper presents a smart method to detect and track the ceramic cell crack initiation and propagating in real time when the solid oxide fuel cell (SOFC) system is in operation with extremely high temperature (>750 deg. C). The main sources of fracture and delamination are the ceramic cell interlayers and interfaces during high temperature thermocycling. This research work is to successfully discern the damages during assembly, initial damages at first thermocycle and damage propagation, if any, at later cycles. This paper demonstrates that the AE signals generated from cell cracking and fracture in the stack modules can be successfully captured by commercially off the shelf (COTS) AE experimental hardware. The distinguishing characteristics of the cell crack AE signal and the metal impact AE signals will be presented in the paper. The second case successfully demonstrates the application of acoustic emission sensors to detect the first crack initiated due to crushing load on ceramic balls. A comprehensive strategy to capture the crushing load with respect to first crack initiation has been developed and would be presented in this paper. The crack is initiated when the Hertzian contact stresses are higher than the crushing load limit. Some initial results on signal processing to distinguish between first and second crack initiation would be presented.

This article reports the results of a study regarding the development of a system to detect the impact damage in composite materials, which is a critical issue concerning aircraft structure. The authors developed a system that could detect the occurrence and growth of damage in composite materials using an FBG optical fiber/PZT actuator hybrid sensor system. In this research, the authors investigate whether or not this system can be used for the detection of both the impact and the damage generated as its result; this system was developed for detecting damages such as the delamination and debonding of the aircraft structure. Basically, the obtained results indicate that the developed damage monitoring system could receive elastic waves that were generated by impacts at energies up to 26.4 J and could also detect the impact damage. These results indicate the possibility of two application by the same system construction by which the damage monitoring using the FBG and PZT hybrid sensor system can detect both the occurrence and growth of damage and the impacts and the damage generated as its result.

A major reason why structural health monitoring (SHM) has still not come into the successful application is the lack of being able to describe the resulting cost advantages SHM might have when being implemented on components of an engineering system. This paper provides an idea how the maintenance process of a mechanical system such as an aircraft can be simulated by using a commercial software tool named ARENA. The procedure allows the different structural components to be inspected along the critical path of an optimised maintenance process to be identified. The critical components are then assessed in terms of SHM implementation and the solution is fed back into the maintenance process simulation. The original and the modified processes are finally compared in terms of duration and cost with the objective to enhance aircraft operability. The procedure is illustrated on the basis of different aerospace applications.

Parallel kinematics offer a high potential for increasing performance of machines for handling and assembly. Due to greater stiffness and reduced moving masses compared to typical serial kinematics, higher accelerations and thus lower cycle times can be achieved, which is an essential benchmark for high performance in handling and assembly. However, there are some challenges left to be able to fully exploit the potential of such machines. Some of these challenges are inherent to parallel kinematics, like a low ratio between work and installation space or a considerably changing structural elasticity as a function of the position in work space. Other difficulties arise from high accelerations, which lead to high dynamic loads inducing significant vibrations. While it is essential to cope with the challenges of parallel kinematics in the design-process, smart structures technologies lend themselves as means to face some of these challenges. In this paper a 4-degree of freedom parallel mechanism based on a triglide structure is presented. This machine was designed in a way to overcome the problem of low ratio between work and installation space, by allowing for a change of the structure's configuration with the purpose of increasing the work space. Furthermore, an active vibration suppression was designed and incorporated using rods with embedded piezoceramic actuators. The design of these smart structural parts is discussed and experimental results regarding the vibration suppression are shown. Adaptive joints are another smart structures technology, which can be used to increase the performance of parallel kinematics. The adaptiveness of such joints is reflected in their ability to change their friction attributes, whereas they can be used on one hand to suppress vibrations and on the other hand to change the degrees of freedom (DOF). The vibration suppression is achieved by increasing structural damping at the end of a trajectory and by maintaining low friction conditions otherwise. The additional feature to alter the DOF is realized by increasing friction to the point where clamping happens. This can be used to support the change in the machines configuration of parallel kinematics. Two kinds of adaptive joints are presented, both utilizing piezoceramic actuators. The first kind features an adjustable clearance of the slide bearing that provides low friction for high clearance conditions and great friction for reduced clearance. The second kind offers the possibility to reduce the friction by moving the rubbing surfaces dynamically. For both joints experimental results are shown. The paper closes with an outlook on ongoing research in the field of parallel robots for handling and assembly with an emphasis on smart structures technologies.

Building on the success of the two rover geologists that arrived to Mars in January, 2004, NASA's next rover mission is planned for the end of the decade. Twice as long and three times as heavy as Spirit and Opportunity, the Mars Science Laboratory rover will collect Martian soil samples and rock cores and analyze them for organic compounds and environmental conditions that could have supported microbial life now or in the past. MSL meteorological package is called REMS (Rover environmental Monitoring Station). This is a scientific instrument designed to provide in situ, near-surface measurements of Temperature (ground surface and atmosphere), Wind, Pressure, Water Vapour and Ultraviolet Radiation (UV). UV observations at the surface will provide important information necessary to asses the habitability of the near surface environment. REMS UV sensor on MSL rover shall be pointing to the Martian sky. From the beginning, deposition of dust particles on the sensor head was considered by NASA's science office a major concern. Such unpredictable phenomena may attenuate the signal received by the optical sensor, and therefore must be considered by far the largest source of error in the sensor. We have studied the error introduced by Martian dust deposition, as well as by frost formation on REMS UV sensor. Several error mitigation strategies such as the use of magnets where evaluated. Finally, a robotic dust wiper was selected as error mitigation system. An optical sensor with a dust wiper was designed, constructed and pre-qualified for MSL mission. Several brushes where fabricated and tested as to maximize its efficiency with submicron particles dust. An Engineering Model of the Sensor including the dust Wiper technology was fabricated and tested. The prototype was subjected to an early qualification campaign under MSL project requirements. Technology performance and qualification results are presented in this paper. The proposed Dust Wiper technology proves to be a simple, yet effective solution to mitigate the error caused by dust on optical sensors or solar panels operating on dirty atmospheres. Using a novel actuator technology based on SMA fibers, the solution represents a very small increase in Mass and a major improvement in system performance. The actuator technology is now being considered for industrial sectors where mass, reliability and cost reduction are key design goals.

In many applications, it is desired to amplify the motion provided by micropositioning actuators. It is shown that mechanical amplification by lever mechanisms reduces the overall system stiffness, which limits the ability of high frequency operations. In this paper, a hydraulic booster is proposed. If the hydraulic fluid used is not compressible, the system stiffness is not affected. Different designs of the booster are examined experimentally to find a booster without hysteresis. Several experiments are performed to characterize the booster. A model for the booster is proposed and evaluated using experimental data.

An adaptronic strut, developed for compensation of the influence of geometric faults in machine tools with parallel kinematic structure, is examined. A simple oscillator model of the strut is built. First, the equations of motions for this simplified model are derived analytically. These information are used for designing a single variable state control based on the principles of the optimal least quadratic regulator (LQR). Afterwards, the controller concept is extended applying an additional PI-controller. Secondly, the strut is modeled using the commercial multi-body system simulation software Msc.Adams. The required system state which is not explicitly given within Msc.Adams primarily has to be estimated. For this task a Luenberger observer is implemented. A similar single variable state control is developed and both designs are compared among themselves when the adaptronic strut is examined under external loads. Finally, the strut is implemented into the model of the complete machine tool and its influence on the behavior of the machine tool is treated.

This paper discusses the development and testing of two Piezoelectrically driven Hydraulic Pumps (PHP2 & PHP3) utilizing low cost discrete multilayer piezoelectric actuators and low cost structural components. New valve technologies were developed utilizing reed and MEMS valves. Structural optimization was performed to decrease weight and volume. The PHP3 design extracts power from a PZT material with high efficiency despite impedance mismatch between the piezoelectric actuator and fluid by utilizing a hydraulic pendulum energy recovery technique. Hydraulic power of 168 watts can be developed with a pump mass of under 1lb. Flow rate of 2300 cc/min free flow has been demonstrated as well as output pressure greater than 200 bar in the stalled condition. The result of the effort is practical solid state conversion of electrical energy into a useable hydraulic source for actuation systems without having normal rotational wear components. The PHP2 pump was used to power the hydraulic primary flight controls in a RPV technology demonstrator flight tested in November 2006.

A fiber optic system for providing permanent downhole casing strain and shape monitoring is described. The optical sensing technique, deployment strategy, as well as lab and field test results are presented. The system is based on optical frequency domain reflectometry for reading out densely packed arrays of Bragg grating sensors. The feasibility of the approach is established and quantitative measurements of casing strain and shape are presented.

Morphing wings have been discussed since the early days of smart structures. Concepts and demonstrations started mainly in the context of real existing fixed wing aircraft. The complexity of existing aircraft and the limitations in terms of energy required and thus resulting cost made morphing wings mainly impossible to be successfully integrated into existing aircraft designs. Going however to smaller scaled aircraft where designs are less or possibly even not defined at all makes demonstration of morphing wings much more feasible. This paper will therefore discuss some morphing wing issues for micro aerial vehicle (MAV) designs where an MAV is considered to be an air vehicle of around 30 to 50 cm in span and a weight of less than 250 grams. At first the aerodynamics in terms of different wing shapes for such a small type of aircraft will be discussed followed by a design procedure on how to successfully design and analyse a morphing wing MAV. A more detailed description will then be given with regard to adaptively changing a wing's thickness where the actuation principles applied will be outlined in terms of conventional mechanical as well as smart structural solutions. Experimental results achieved in real flight tests will be described and discussed.

The research on self repair of airplane components, under an SBIR phase II with Wright Patterson Air Force Base, has investigated the attributes and best end use applications for such a technology. These attributes include issues related to manufacturability, cost, potential benefits such as weight reduction, and cost reduction. The goal of our research has been to develop self-repairing composites with unique strength for air vehicles. Our revolutionary approach involves the autonomous release of repair chemicals from within the composite matrix itself. The repair agents are contained in hollow, structural fibers that are embedded within the matrix. Under stress, the composite senses external environmental factors and reacts by releasing the repair agents from within the hollow vessels. This autonomous response occurs wherever and whenever cracking, debonding or other matrix damage transpires. Superior performance over the life of the composite is achieved through this self-repairing mechanism. The advantages to the military would be safely executed missions, fewer repairs and eventually lighter vehicles. In particular the research has addressed the issues by correlating the impact of the various factors, such as 1) delivery vessel placement, shape/size and effect on composite strength, chemicals released and their effect on the matrix, release trigger and efficacy and any impact on matrix properties 2) impact of composite processing methods that involve heat and pressure on the repair vessels. Our self repairing system can be processed at temperatures of 300-350F, repairs in less than 30 seconds and does not damage the composite by repair fiber insertion or chemical release. Scaling up and manufacture of components has revealed that anticipating potential problems allowed us to avoid those associated with processing temperatures and pressures. The presentation will focus on compression after impact testing and the placement of repair fibers/tubes into prepreg laminates.

This paper discusses the development and system integration of the Pulse Activated Cell System (PACS) Digital Pump technology using 2 types of electro-activated polymer (EAP) actuators. This is a platform specifically developed for the integration of sensor feedback loops to create an autonomous fluidic monitoring, reaction and delivery system. Initial, proof of concept, performance testing results are discussed as well as development for a medical drug delivery device and higher volume infusion therapy device. Uses and applications of the technology in other industries is considered as the PAC System provides a new ability to pump single or multiple fluid flows in a single pump that is programmable with the ability to vary direction, pressure and flow rates. The result is digital control of fluidic delivery, testing and mixing in application scaleable product packages. This technology will lead to new low cost yet sophisticated fluidic processing products and devices for many industries.

High customization costs and reduction of natural mobility put current rehabilitative knee braces at a disadvantage. A resolution to this problem is to integrate a Magnetorheological (MR) fluid-based joint into the system. A MR joint will allow patients to apply and control a resistive torque to knee flexion and extension. The resistance torque can also be continuously adjusted as a function of extension angle and patient strength (or as a function of time), which is currently impossible with state of the art rehabilitative knee braces. A novel MR fluid-based controllable knee brace is designed and prototyped in this research. The device exhibits large resistive torque in the on-state and low resistance in the offstate. The controllable variable stiffness, compactness, and portability of the system make it a proper alternative to current rehabilitative knee braces.

The microchips inside modern electronic equipment generate heat and demand, each day, the use of more advanced cooling techniques as water cooling systems, for instance. These systems combined with piezoelectric flow pumps present some advantages such as higher thermal capacity, lower noise generation and miniaturization potential. The present work aims at the development of a water cooling system based on a piezoelectric flow pump for a head light system based on LEDs. The cooling system development consists in design, manufacturing and experimental characterization steps. In the design step, computational models of the pump, as well as the heat exchanger were built to perform sensitivity studies using ANSYS finite element software. This allowed us to achieve desired flow and heat exchange rates by varying the frequency and amplitude of the applied voltage. Other activities included the design of the heat exchanger and the dissipation module. The experimental tests of the cooling system consisted in measuring the temperature difference between the heat exchanger inlet and outlet to evaluate its thermal cooling capacity for different values of the flow rate. Comparisons between numerical and experimental results were also made.

Bio-inspired actuation, such as flapping of flying insect, has been an attracted research subject because of their superior maneuverability at low Mach number flight. Flapping mechanism of biological flying insects and birds have been identified as the promising ones for future micro- or nano- air vehicles (MAV or NAV) for stealth surveillance applications. The kinematics of flapping wings is very complicated, including flapping and rotating. One promising thorax actuator design to mimic motions of flapping wings is based on ferromagnetic shape memory alloy (FSMA) composite which is made of superelastic SMA and soft iron. FSMA composite has been proved as a promising actuator material for fast responsive and robust actuators based on hybrid mechanism. We designed a prototype thorax actuator based on the FSMA composite and hybrid mechanism concept. Our preliminary tests show that the NiTi/polymer composite wing swings back and forth with 60 degree at 22Hz which is close to its resonance frequency. Toward the end of each flapping cycle, the wing also rotates due to the inertia force as passive rotation. The flapping angle is so large that a high stress is induced on the NiTi wing frame near the fixture therefore a stress-induced martensite transformation (SIM) occurs with large elastic strain. Because of this superelastic property of NiTi, the wing frame will spring back.

The integration of piezoceramic based sensors and actuators offers a possibility to produce multifunctional materials with enhanced properties. Die casting is an innovative approach for the fabrication of metal matrix smart structural components where the functional module is totally integrated in the interior of the cast part. A technique to support and protect the sensitive sensor/actuator-modules in the die during the highly dynamic die filling process is presented. Demonstration parts were produced which are fully capable to be activated to vibrate. An approach to characterize in detail the behavior of the sensor/actuator-module after the integration in the cast matrix is presented. Both FE computation and electric impedance measurements are used to quantify how the casting process affects the performance of the integrated sensor/actuator-modules.

Piezoelectric actuators for diesel fuel injection are subjected to a highly transient square pulse voltage excitation. A treatment of this modeling problem provides insight into a stress field inside the stack, highlighting a possibility of tensile stresses developing immediately after an application and a removal of voltage. Modeling offers an opportunity for optimization of the stack geometry for the best performance and response under the constraints of available space envelope, peak electric current and compressive prestress.

The field of Smart Materials and Structures is evolving from high-end, one-of-a-kind products for medical, military and aerospace applications to the point of viability for mainstream affordable high volume products for automotive applications. For the automotive industry, there are significant potential benefits to be realized including reduction in vehicle mass, added functionality and design flexibility and decrease in component size and cost. To further accelerate the path from basic research and development to launched competitive products, General Motors (GM) has teamed with the College of Engineering at the University of Michigan (UM) to establish a $2.9 Million Collaborative Research Laboratory (CRL) in Smart Materials and Structures. Researchers at both GM and UM are working closely together to create leap-frog technologies which start at conceptualization and proceed all the way through demonstration and handoff to product teams, thereby bridging the traditional technology gap between industry and academia. In addition to Smart Device Technology Innovation, other thrust areas in the CRL include Smart Material Maturity with a basic research focus on overcoming material issues that form roadblocks to commercialism and Mechamatronic System Design Methodology with an applied focus on development tools (synthesis and analysis) to aid the engineer in application of smart materials to system engineering. This CRL is a global effort with partners across the nation and world from GM's Global Research Network such as HRL Laboratories in California and GM's India Science Lab in Bangalore, India. This paper provides an overview of this new CRL and gives examples of several of the projects underway.

Pedestrian protection is a major focus of automotive crashworthiness with new regulations taking effect worldwide. While there are many approaches to reducing the head-injury-criteria (HIC), a leading approach is to actively lift the hood to increase the crush distance to rigid underhood components. Most current lift devices are single-use, requiring the hood to be manually returned to a drivable position, and may damage the hood during lift due to inappropriate lift rates. This paper addresses these issues with an alternative approach using stored energy marrying conventional (pneumatic) and smart materials (Shape Memory Alloy) actuation. The SMART (SMA ReseTtable) hood lift device comprises a dual chamber cylinder which releases stored pneumatic energy via an ultra-fast SMA exhaust valve, raising a piston attached to the hood. The device can be automatically reset and rearmed through pressurization of the chambers and the energy dissipated for service by evacuating both chambers. This approach is unique in that several design parameters such as pressure and valve opening/timing profile can be altered in the field to compensate for temperature, added mass (such as snow) or platform changes. This paper presents the concept of this device and the parametric design of the pneumatic cylinder and valve orifice based on an analytical performance model. Two valve concepts are presented: direct and indirect, where the direct valve is simpler and more controllable, but the indirect valve can provide larger orifices (and therefore faster lift times) with reduced actuation requirements. Using a combination of analytical model-based and experimental methods, the SMART lift device with each valve approach was designed, and a full-scale prototype built and experimentally characterized validating the model and successfully demonstrating feasibility of each system to meet and exceed the pedestrian protection specifications. This new set of technologies enables the hood lift application with added functionality such as tailorability and resettability.

This paper presents a mechatronic strategy for active reduction of vibrations on machine tool struts or car shafts. The active structure is built from a carbon fiber composite with embedded piezofiber actuators that are composed of piezopatches based on the Macro Fiber Composite (MFC) technology, licensed by NASA and produced by Smart Material GmbH in Dresden, Germany. The structure of these actuators allows separate or selectively combined bending and torsion, meaning that both bending and torsion vibrations can be actively absorbed. Initial simulation work was done with a finite element model (ANSYS). This paper describes how state space models are generated out of a structure based on the finite element model and how controller codes are integrated into finite element models for transient analysis and the model-based control design. Finally, it showcases initial experimental findings and provides an outlook for damping multi-mode resonances with a parallel combination of resonant controllers.

Presented here is an innovative class of piezoelectric-based generators for application in gun-fired munitions and other similar devices. The generators are designed to produce electrical energy as a result of the firing acceleration with enough output to power certain on-board electronic circuitry, such as lowpower fuzing. In this class of piezoelectric-based generators, a novel mechanism is provided with which the strain applied to the piezoelectric stack can be maintained at its in-firing peak value throughout the flight of the projectile. As a result, the generated charge can be harvested efficiently during a significantly longer period of time. In addition, in some munitions applications this can totally eliminate the need for storing the generated electrical energy in another storage medium. This class of impact-based piezoelectric generator devices is intrinsically robust in design which makes it suitable for high-G applications. Also, since the present devices produce energy due to the firing acceleration, a high degree of safety is guaranteed because the electronics are not powered until the projectile is fired. A basic proof-of-concept design and a deployable prototype concept are presented which will demonstrate the scalability of the present devices as well as their survivability in high-G environments.

A novel class of piezoelectric-based energy-harvesting power sources is presented for gun-fired munitions and other similar applications that require very high G survivability. The power sources are designed to harvest energy from the firing acceleration as well as vibratory motion of munitions during the flight and convert it to electrical energy to power onboard electronics. The developed piezoelectric-based energy harvesting power sources produce enough electrical energy for applications such as fuzing. The power sources are designed to withstand firing accelerations in excess of 100,000 G. In certain applications such as fuzing, the developed power sources have the potential of completely eliminating the need for chemical batteries. In fuzing applications, the developed power sources have the added advantage of providing additional safety, since with such power sources the fuzing electronics are powered only after the munitions have exited the barrel and have traveled a safe distance from the weapon platform. The design of a number of prototypes, including their packaging for high G hardening, and the results of laboratory and air-gun testing are presented. Methods to increase the efficiency of such energy-harvesting power sources and minimize friction and damping losses are discussed.

A novel class of vibration-based electrical energy generators is presented for applications in which the input rotary speed is relatively low and varies significantly over time such as wind mills, turbo-machinery used to harvest tidal flows, and the like. Current technology uses magnet and coil based rotary generators to generate electrical energy in such machinery. However, to make the generation cycle efficient, gearing or other similar mechanisms have to be used to increase the output speed. In addition, variable speed mechanisms are usually needed to achieve high mechanical to electrical energy conversion efficiency since speed variation is usually significant in the aforementioned applications. The objective of the present work is the development of electrical energy generators that do not require the aforementioned gearing and speed control mechanisms, thereby significantly reducing complexity and cost, particularly those related to maintenance and service. This novel class of electrical energy generators operates based on repeated vibration of multiple vibrating elements that are tuned to vibrate at a fixed prescribed frequency. The mechanical energy stored in the vibration elements is transformed into electrical energy using piezoelectric elements. The present generators are very simple, can efficiently operate over a very large range of input speeds, and should require minimal service and maintenance. The project is at the early stages of its development, but the analytical modeling and computer simulation studies using realistic system and component parameters indicate the potentials of this class of piezoelectric-based generators for the indicated applications.

Magnetorheological energy absorbers (MREAs) have been identified as a candidate for tunable impact energy absorber applications, meaning those in which a high shock load is applied during a short time period. In this study, we focused on the theoretical analysis, design and laboratory implementation of a compact high force MREA for shock and impact loads. This study included the design and fabrication of a flow-mode bifold MREA (magnetorheological energy absorber) that operates under piston velocities up to 6.71 m/s and the development of a hydro-mechanical analysis to predict MREA performance. Experiments were conducted both in the laboratories at UMCP (sinusoidal excitation) and at GM R&D (drop tower tests), and these data were used to validate the analysis. The hydro-mechanical model for the MREA was derived by considering lumped hydraulic parameters which are compliances of MR fluids inside the cylinder and flow resistance through the MR bifold valves. The force behavior predicted by the hydro-mechanical analysis was simulated for two classes of inputs: sinusoidal displacement inputs, and shock loads using a drop tower. At UMCP, sinusoidal inputs ranging up to 12 Hz with an amplitude of 12.7 mm were used to excite the MREA using three different MR fluids, each having an iron volume fraction of nominally 35%, 40% and 45%. Subsequently, drop tower tests were conducted at GM R&D by measuring MREA performance resulting from the impact of a 45.5 kg (100 lb) mass dropped onto the MREA shaft at speeds of 1, 2 and 3 m/s. Comparison of the simulations with experimental data demonstrated the utility of the hydro-mechanical model to accurately predict MREA behavior for the specified ranges of sinusoidal and shock classes of inputs.