This paper presents a new class of highly efficient piezoelectric based energy harvesting power sources for mounting on platforms that vibrate at very low frequencies as compared to the frequencies at which energy can be efficiently harvested using piezoelectric elements . These energy harvesting power sources have a very simple design and do not require accurate tuning for each application to match the frequency of the platform vibration. The developed method of harvesting mechanical energy and converting it to electrical energy overcomes problems that are usually encountered with harvesting energy from low frequency vibration of various platforms such as ships and other platforms with similar vibratory (rocking or translational) motions. Omnitek Partners has designed several such energy harvesting power sources and is in the process of constructing prototypes for testing. The developed designs are modular and can be used to construct power sources for various power requirements. The amount of mechanical energy available for harvesting is obviously dependent on the frequency and amplitude of vibration of the platform, and the size and mass of the power source.

There are numerous engineering design problems where the use of wires to transfer power and communicate data thru the walls of a structure is prohibitive or significantly difficult that it may require a complex design. Using physical feedthroughs in such systems may make them susceptible to leakage of chemicals or gasses, loss of pressure or vacuum, as well as difficulties in providing adequate thermal or electrical insulation. Moreover, feeding wires thru a wall of a structure reduces the strength of the structure and makes the structure prone to cracking due to fatigue that can result from cyclic loading and stress concentrations. One area that has already been identified to require a wireless alternative to electrical feedthroughs would be the container of any Mars Sample Return Mission, which would need wireless sensors to sense a pressure leak and to avoid potential contamination. The idea of using elastic or acoustic waves to transfer power was suggested recently by [Y. Hu, et al., July 2003]. This system allows for the avoidance of cabling or wiring. The technology is applicable to the transfer of power for actuation, sensing and other tasks inside any sealed container or vacuum/pressure vessel. An alternative approach to the modeling presented previously [Sherrit et al., 2005] used network analysis to solve the same problem in a clear and expandable manner. Experimental tests on three different designs of these devices were performed. The three designs used different methods of coupling the piezoelectric element to the wall. In the first test the piezoelectric material was bolted using a backing structure. In the second test the piezoelectric was clamped after the application of grease. Finally the piezoelectric element was attached using a conductive epoxy. The mechanical clamp with grease produced the highest measured efficiency of 53% however this design was the least practical from a fabrication viewpoint. The power transfer efficiency of conductive epoxy joint was 40% and the stress bolts (12%). The experimental results on a variety of designs will be presented and the thermal and non-linear issues will be discussed.

This paper presents results of ongoing research that addresses possible geometric inaccuracies and structural deficiencies arising from nonuniform heating and cooling of parts fabricated or repaired using laser powder deposition. A "smart-structures" based method is investigated, in which piezoelectric (and/or mechanical) actuators provided on the substrate are used sequentially to deform and undeform a substrate through deposition with the goal of minimizing the residual deformations/stresses in the part. Different actuation configurations are considered, and results based on linear theory are discussed. Initial experimental work is also described. Results to date indicate that the approach could be used to advantage in certain types of builds for active control/reduction of residual deformations/stresses in laser deposited parts.

In some types of aircraft tonal interior noise with high sound pressure level (up to 110 dB(A)) occurs at low frequencies (f < 500 Hz). Typical examples are propeller driven aircraft, for which the excitation frequencies are given by the blade passage frequency (BPF) and its higher harmonics. The high tonal noise levels at these frequencies can occur due to the fact that the blades' profiles are only optimized in terms of aerodynamics. The acoustic properties are usually not taken into account. In order to obtain an acceptable interior noise level, and to guarantee both work-safety and comfort in the aircraft interiors, passive methods are commonly used - e.g. adding material with high damping or vibration absorbing qualities. Especially when low frequency noise has to be reduced, adding material results in a lot of unwanted additional weight. In order to avoid this extra weight, the concept of active noise reduction (ANR) and tunable vibration absorber systems (TVA), which focus on the unwanted tonal noise, are a good compromise of treating noise and the amount of additional weight in aircraft design. This paper briefly discusses two different possible methods to reduce the low frequency noise. The noise reduction of tuned vibration absorbers (TVA) mounted on the airframe are nowadays commonly used in propeller driven aircraft and can be predicted by vibroacoustic finite element calculations, which is described in this paper. In order to abide to industrial safety regulations, the noise level inside the semi closed loadmaster area (LMA) must be reduced down to a noise level, which is even 8 dB(A) below the specified cargo hold noise level. The paper describes also the phases of development of an ANR system that could be used to control the sound pressure level inside the LMA. The concept is verified by experimental investigations within a mock up of the LMA.

Effects of sheet electron beam irradiation on impact strength and wettability of alkali-free glass were studied. The irradiation, which was one of short-time treatments at low temperature below boiling point of water, enhanced impact value, whereas it decreased contact angle of alkali-free glass surface. EB irradiation also enhanced wettability and mist resistance.

Future NASA exploration missions will increasingly require sampling, in-situ analysis and possibly the return of material to Earth for laboratory analysis. To address these objectives, effective and optimized drilling techniques are needed. This requires developing comprehensive tools to be able to determine analytically what takes place during the operation and what are the control parameters that can be enhanced. In this study, three types of coring techniques were studied and were identified as potential candidates for operation from a possible future Mars Sample Return (MSR) mission rover. These techniques include percussive, rotary-friction, and rotary-percussive coring. Theoretical models were developed to predict the dynamic reaction forces transmitted from these three types of corers to the robotic arms that hold them. The predicted reaction forces will then be used in a dynamic simulation environment to simulate a representative corer tool to obtain a best estimate of a tool that can be operated from a small rover. The predicted dynamic reaction forces will be presented in this paper.

Rock, soil, and ice penetration by coring, drilling or abrading is of great importance to a large number of space and earth applications. Proven techniques to sample Mars subsurface will be critical for future NASA astrobiology missions that will search for records of past and present life on the planet. An Ultrasonic/Sonic Drill/Corer (USDC) has been developed as an adaptable tool for many of these applications [Bar-Cohen et al., 2001]. The USDC uses a novel drive mechanism to transform the ultrasonic or sonic vibrations of the tip of a horn into a sonic hammering of a drill bit through an intermediate free-flying mass. The USDC design was modified to fabricate an Ultrasonic/Sonic Ice Gopher that is designed to core down to meters depth for in situ analysis and sample collection. This technology was demonstrated at Lake Vida in the Dry Valleys, Antarctica. Coring ice at -20°C as in Lake Vida has been a challenge and efforts were made to develop the required ice core cutting, ice chip handling and potential ice melting (and refreezing) during drilling. The analysis and fabrication challenges and testing results are presented in this paper.

Environment protection requires more testing and analysis tools. To detect buried chemical containers or other objects embedded in soil and avoid possible damage to them, a penetrator was developed for packed soil that requires low penetration force (the force needed to push rod probe into the soil). The design was based on the novel mechanism used by the ultrasonic/sonic driller/corer (USDC) that was developed jointly by scientists at the NDEAA lab at JPL and engineers at Cybersonics, Inc. [Bar-Cohen et al 2001, Bao et al 2003]. In the penetrator, a small free-flying mass is energized by a piezoelectric transducer and impacts a rod probe on its shoulder at frequencies of several hundred Hetz. The impacts help the probe to penetrate the packed soil with low pushing force. A large reduction of the penetration force was achieved. Preliminary tests show that the effects of the penetrator on plastic containers and other objectors are minimal. The details of the design of the prototype penetrator and the results of performance tests are presented.

Precision flow pumps have been widely studied over the last three decades. They have been applied as essential components in thermal management solutions for cooling electronic devices offering better performance with low noise and low power consumption. In this work, a novel configuration of a miniature piezoelectrically actuated flow pump with the purpose of cooling a LED set inside a head light system for medical applications has been studied and it will be presented. The complete cycle of pump development was conducted. In the design step, the ANSYS finite element analysis software has been applied to simulate and study the fluid-structure interaction inside the pump, as well as the bimorph piezoelectric actuator behavior. In addition, an optimization process was carried out through Altair Hyperstudy software to find a set of parameter values that maximizes the pump performance measured in terms of flow rate. The prototype manufacturing was guided based on computational simulations. Flow characterization experimental tests were conducted, generating data that allows us to analyze the influence of frequency and amplitude parameters in the pump performance. Comparisons between numerical and experimental results were also made.

The integration of smart materials such as piezoelectric devices and shape memory alloys into structures has been typically limited to a bonding process that occurs as a secondary operation. Such an operation is not only costly for high volume applications but also has the potential of degrading the performance of the actuator or sensor due to the bonding agent selected. The work presented here explores the integration of piezoelectric materials using a high volume injection molding process. The process used is typical for large automotive components such as bumpers, instrument panels and other body panels. Different materials were evaluated, including plastics and both bare and packaged smart materials. Temperature and flow rate were also changed to investigate the effects on the durability of the materials. Both electrical and mechanical properties were tested with the key parameters including, void content, shifting from initial position, strain transfer and peal strength. It was found that good integration of piezoelectric materials could be achieved and electro-mechanical properties were improved as compared to a secondary bonding operation. Integration of screen-printed electrical circuits for electrical connectivity for piezoelectric materials will be evaluated in future research. In conclusion, a step forward was made in developing a multifunctional material based upon smart materials and conventional high volume manufacturing processes.

Fiber optic pressure sensors were integrated into the grinding plates of an operational paper pulp mill for real-time monitoring of the pulp grinding process. On-line system monitoring will allow smart, active control of the grinding plates thereby improving the quality and consistency of the pulp produced. Sensors were constructed and calibrated for use in the harsh environment of an operating paper pulp grinder. The sensors were 1.65mm in diameter including titanium housing, and were installed directly into the grooves of the grinding plates. The sensing elements were flush-mounted with the wall and exposed to the wood pulp slurry. Nine sensors were calibrated up to 1000psi. During operation, pressure was sampled at 1.0MHz, and pressure spikes up to 175psi were observed. Pressure pulses measured are due to the relative motion between the grooves and channels on two pulp grinding plates. The consistency, size distribution, and quality of paper pulp exiting from the grinder are directly related to the distance between the channels on the two rotating elements. The pressure pulses produced are also proportional to the distance between channels. Therefore, by monitoring pressure fluctuations, grinding elements can be dynamically controlled thereby producing a "smart mill."

This study is about some of the results of the test performed for the purpose of developing the damage monitoring system with the advanced composite bonding structure applied to a next generation aircraft. Through the past researches, we succeeded in receiving hundreds of kHz of elastic waves (lamb waves) launched from PZT byusing an optical fiber sensor bonded to or embedded in a specimen. Furthermore, by using an FBG optical fiber sensor embedded in the bonding interface of a CFRP coupon specimen or a structure element specimen with skin/stringer bonded structure or bonded to the surface of the specimen, the test results have been proven and the fact is verified that regarding the structure of composites, variations of elastic waves according to damage growth can be received with high accuracy. The authors also suggest it is possible to detect a damage, which is generated inside composites by calculating the elastic waves. For this study, we manufactured a structural element specimen where a small-diameter optical fiber sensor is embedded in the bonding interface, which is simulated a skin/stringer bonding structure of actual composite structures. We also developed the system, which is detecting elastic (lamb) wave up to 1MHz on our own and optimized it according to the corresponding specimen. Furthermore, an artificial damage is installed to critical area of the structural element specimen as a damage origin point. It is verified that our monitoring system can detect the variations of elastic waves accompanying the damage of 20mm2 occurring and growing from the artificial damage by the applied cyclic load.

There is a growing demand for lightweight structures in aircraft systems for realizing energy and cost savings. The authors are developing a new lightweight grid structure for aircraft applications equipped with a health monitoring system utilizing fiber Bragg grating (FBG) sensors. The grid structure has a very simple path for stress, which is easily detected by FBG sensors embedded in the ribs. In this research, the difference in the strain distributions before and after damage to the grid structure was evaluated analytically, and a damage detection method was established. The correspondence between damage detection ability and damage tolerance design strength was clarified. Furthermore, the damage tolerance design method was established based on the evaluation of residual strength corresponding to the detected damage level of rib. Next, the prototype of a highly reliable grid structure embedded with FBG sensors was manufactured, and the damage detection ability was experimentally verified. The panel size of the specimen was 525 x 550 mm and 29 FBG sensors were embedded at the center of the panel. Load was applied on the grid panel, and the strain distribution was measured by the multipoint FBG sensors. The artificial damage introduced in one rib of the specimen and the position of the damage, were successfully detected by comparing the strain distributions before and after the introduction of the damage.

The most important project in sheet metal forming is streamlining the material flow since each rejects increases production costs. Using the multipoint cushion device together with an elastic blankholder makes it possible to actively manipulate the material flow in the flange range. This allows major enhancements in the deformation ratio, especially with the novel high strength materials in car body production. State-of-the-art is multiple draw pins to initiate the force on selected points on the blankholder. Admittedly, the cushion plate does not allow optimum force allocation because it is situated between hydraulic pressure rollers and draw pins. Replacing selected draw pins with piezoactuators for generating high forces allows systematic control of the force progression at critical forming areas during sheet draw-in. The system, consisting of the piezostack actuator, dynamometer and components for force initiation, was built as a compact unit with low resilience with the intension of using the inherent sensory properties of the piezostack actuator to measure force. Applying this principle throughout allows a reduction of hydraulic components which eventually lead to a less expensive one- point cushion device. Initial finding have already been arrived at in the context of a research project at the Fraunhofer Institute for Machine Tools and Forming Technology in Chemnitz, Germany in cooperation with a partner from the automobile industry. A draw pin was replaced ad hoc with a highly durable piezoactuator integrated in a force control cycle. The force progression during the sheet draw-in could be accurately adjusted according to a predetermined master curve. The master curve was taken up in the unregulated process and represents the quality criteria of a formed useable part. The real-time MATLAB Simulink XPC- Target simulation tool was used to develop an adjustment strategy that connects the specific signals of the press control (such as the tappet path, the die cushion position and the die cushion force) with the reference force (i.e., the master curve) and the actual force of the piezoactuator.

The use of Shape Memory Alloys (SMAs) is growing rapidly. They have been under serious development for aerospace applications for over 15 years, but are still restricted to niche areas and small scale applications. Very few applications have found their way into service. Whilst they have been predominantly aimed at airframe applications, they also offer major advantages for adaptive gas turbine components. The harsh environment within a gas turbine with its high loads, temperatures and vibration excitation provide considerable challenges which must be met whilst still delivering high integrity, light weight, aerodynamic and efficient structures. A novel method has been developed which will deliver high integrity, stiff mechanical components which can provide massive shape change capability without the need for conventional moving parts. The lead application is for a shape changing engine nozzle to provide noise reduction at take off but will withdraw at cruise to remove any performance penalty. The technology also promises to provide significant advantages for applications in a gas turbine such as shape change aerofoils, heat exchanger controls, and intake shapes. The same mechanism should be directly applicable to other areas such as air frames, automotive and civil structures, where similar high integrity requirements exist.

This paper deals with the microstructure of the generated crystals in borate glass by femtosecond laser irradiation, Raman spectroscopy was used to study the distribution of the high temperature and low temperature phases of barium metaborate crystals produced in the borate glass, and the mechanism was discussed.

The disadvantage of current knee braces ranges from high cost for customization to a loss in physical mobility and limited rehabilitative value. One approach to solving this problem is to use a Magnetorheological (MR) device to make the knee brace have a controllable resistance. Our design solution is to replace the manufacturer's joint with an rotary MR fluid based shear damper. The device is designed based on a maximum yield stress, a corresponding magnetic field, a torque and the MR fluid viscosity. The analytical and experimental results show the advantages and the feasibility of using the proposed MR based controllable knee braces.

The idea of this paper is to design a Magnetorheological (MR) fluid based damper for steer-by-wire systems to provide sensory feedback to the driver. The advantages of using MR fluids in haptic devices stem from the increase in transparency gained from the lightweight semiactive system and controller implementation. The performance of MR fluid based steer-by wire system depends on MR fluid model and specifications, MR damper geometry, and the control algorithm. All of these factors are addressed in this study. The experimental results show the improvements in steer-by-wire by adding force feedback to the system.

This research is conducted to demonstrate the advantages of skyhook semi-active dampers in railway vehicle suspension systems. This semi- active suspension system consists of four actuators on each bogie that locate in the secondary suspension position instead of passive dampers. Employing equations of skyhook control scheme, the semi- active damping force (actuator force) is determined by absolute velocity of car body instead of relative velocity. An integration of a control design tool, i.e. MATLAB, together with a tool for railway vehicle simulation, i.e. ADAMS/Rail is utilized for modeling and control analysis simultaneously. Analysis has been performed on a traditional bogie model with passive secondary suspension and on a new bogie model with semi-active suspension. The effects of suspension system on displacement and acceleration in passenger seats have been investigated in various points of car body. Results show that the semi-active suspension improves the ride comfort by reducing accelerations, in comparison with passive model. Finally, according to the damper force obtained from Sky-hook controller, a Magnetorheological (MR) damper has been designed for the semi-active suspension system.

Cornerstone Research Group, Inc. (CRG) has demonstrated the feasibility of filament winding complex-curved composite shapes on shape memory polymer (SMP) mandrels. SMPs can exhibit a radical change from a rigid polymer to a flexible, elastic state, and then back to a rigid state under thermal stimuli. SMP mandrels for filament winding and fiber placement allow for a quick, easy, reusable, and low-cost mandrel system. CRG has recently improved the SMP mandrel technology by adding a high-strain fiber reinforcement (HSFR) that both raises the toughness of the SMP and allows the SMP to elongate up to 150 percent. The resulting material can produce mandrels durable enough to withstand multiple use in high production rate manufacturing. This paper will demonstrate and discuss the feasibility of HSFR-SMP mandrels for filament winding and fiber placement and recent developments in CRG's SMP mandrel technology, including the fabrication of larger parts.

Different systems and strategies have been invented in order to reduce the noise level inside the fuselage of aircrafts. First of all passive methods like adding materials with high damping or vibration absorbing qualities were used. Due to mass reduction as a major aspect in aircraft design a lot of research is focused on active noise reduction (ANR). The level of attenuation gained by an ANR - system is depending on several attributes of the system like hardware and software in use. Another important parameter, which has a great impact on the performance, is the positioning of the actuators and sensors. Because of the high number of possible arrangements of actuators and sensors in three dimensional spaces, it is almost impossible to determine the optimal positions by experimental work. Therefore numerical optimization is applied. In this paper a hybrid evolutionary algorithm is introduced for the calculation of appropriate configurations for a fixed number of actuator and sensors out of a high number of possible positions for an ANR - system within a military aircraft. The presented COSA - algorithm (cooperative simulated annealing) connects qualities of two well known optimization algorithms, the simulated annealing (SA) and genetic algorithm (GA). A general description of the algorithm and the acoustical basics will be provided together with an overview of the results.

Boeing is applying cutting edge smart material actuators to the next generation morphing technologies for aircraft. This effort has led to the Variable Geometry Chevrons (VGC), which utilize compact, light weight, and robust shape memory alloy (SMA) actuators. These actuators morph the shape of chevrons on the trailing edge of a jet engine in order to optimize acoustic and performance objectives at multiple flight conditions. We have demonstrated a technical readiness level of 7 by successfully flight testing the VGCs on a Boeing 777-300ER with GE-115B engines. In this paper we describe the VGC design, development and performance during flight test. Autonomous operation of the VGCs, which did not require a control system or aircraft power, was demonstrated. A parametric study was conducted showing the influence of VGC configurations on shockcell generated cabin noise reduction during cruise. The VGC system provided a robust test vehicle to explore chevron configurations for community and shockcell noise reduction. Most importantly, the VGC concept demonstrated an exciting capability to optimize jet nozzle performance at multiple flight conditions.