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Piezoelectric Ultrasonic motors (USM) are based on the principle of converse piezoelectric effect i.e., vibrations occur when an electrical field is applied to piezoelectric materials. USMs have been studied several decades for their advantages over traditional electromagnetic motors. Despite having many advantages, they have several challenges too. Recently many researchers have started focusing on Industry 4.0 or Fourth Industrial revolution phase of the industry which mostly emphasis on digitization & interconnection of the entities throughout the life cycle of the product in an industrial network to get the best possible output. Industry 4.0 utilizes various advanced tools for carrying out the nexus between the entities & bringing up them on digital platform. The studies of the role of USMs in Industry 4.0 scenario has never been done till now & this article fills that gap by analyzing the piezoelectric ultrasonic motors in depth & breadth in the background of Industry 4.0. This article delivers the novel working principle, illustrates examples for effective utilization of USMs, so that it can buttress the growth of Industry 4.0 Era & on the other hand it also analyses the key Industry 4.0 enabling technologies to improve the performance of the USMs.

Vibration-based energy harvesting using piezoelectric stacks has received increasing attention in recent years for its higher mechanical-to-electrical energy conversion capability in the d33 mode. However, most research on this type of harvesters is based on either the simplified one-degree-of-freedom model or transfer matrix model. This paper presents a distributed-parameter model for the multilayer piezoelectric stack transducer based on the axial vibration theory of a continuous bar. The presented analytical model is free from the assumption that the generated current is identically distributed over all the piezoelectric layers, which has been widely used by the existing models in literature. A first-order numerical model is also introduced to validate the performance of the analytical model on the prediction of voltage, current and power outputs of the harvester under different types of external excitations. Both the analytical and numerical models are firstly validated by experiments and then are used to predict the electrical responses of the stack harvester under general periodic and random excitations with different intensities. Experiment and simulation results demonstrate that the proposed distributed-parameter model has a good accuracy and reliable performance in the prediction of the electrical responses.

A footwear harvester needs to fulfill both technical and practical functionalities, including but not limited to energy extracting and storage, easy implantation and durability. The very limited space in a shoe is the key challenge to the design of a footwear harvester. This paper presents the design, optimization, modeling and testing of an embedded piezoelectric footwear harvester for energy scavenging from human walking. A force amplification frame is designed and optimized to transmit and amplify the vertical heel-strike force to the inner piezoelectric stack deployed in the horizontal direction. Two heel-shaped aluminum plates are employed to gather and transfer the dynamic force over the heel to the sandwiched force amplification frames. The dynamic force at the heel is measured to design, optimize and simulate the piezoelectric footwear harvester. A numerical model is developed and validated to be capable of precisely predicting the electrical outputs of the harvester. Two prototypes, respectively including eight and six stacks, are fabricated and tested on a treadmill at different walking speeds and external resistances. The numerical simulations agree well with experiments. The harvester with fewer piezoelectric stacks could produce more power at the same walking speed and matched resistance. Experimental results manifest that the footwear harvesters with eight and six stacks, respectively, have 7 mW/shoe and 9 mW/shoe average power outputs at the walking speeds of 3.0 mph (4.8 km/h). Simulation results from the validated numerical model show that the harvester with four piezoelectric stacks could harvest 14 mW/shoe and 20 mW/shoe average power at 3.0 mph (4.8 km/h) and 3.5 mph (5.6 km/h), respectively.

Massive dissipated kinetic energy of roadway traffic is a sustainable energy source that can be harvested via piezoelectric effect. The piezoelectric energy harvesting technology provides a robust and reliable solution of roadway power generation. However, it remains challenging to achieve high energy density in order for the harvested energy to be of utility value. Here, we demonstrate an innovative roadway piezoelectric energy harvesting system, which reaches an energy density as high as 15.37 J/(m.pass.lane) based on the open-circuit voltage measurements in road tests. The high energy density is achieved by incorporating a compression-to-compression force amplification mechanism as well as an optimized system configuration to take full advantage of dynamic load from vehicles. To the best of our knowledge, the prototype system has achieved the highest energy density reported in the literature, and holds the great potential to be part of the smart highway.

A “33” mode (mechanical stress being in parallel to the electric dipole moment direction) piezoelectric lead zirconate titanate (PZT) multilayer stack-based piezoelectric flextensional energy harvester (PZT-Stacked-FEH) has been developed. Interdisciplinary approaches had been taken to increase the performance of the PZT-Stacked-FEH. First, an elastic flextensional frame for force amplification has been optimally designed to capture more mechanical energy with high energy transition efficiency into the PZT-Stacked-FEH. Second, a “33” mode piezoelectric PZT multilayer stack (PZT-Stack) was employed instead of “31” mode (stress being in perpendicular to the dipole moment direction) single layer piezoelectric component to increase mechanical to electrical energy conversion efficiency and to generate more electrical charges in order to improve energy storage efficiency. With these approaches, the PZT-Stacked-FEH demonstrates excellent performance: 1) a 19% of overall mechanical to electrical energy conversion efficiency was achieved, 2) 48.6 times more mechanical energy was transited into PZT-Stacked-FEH and 26.5 times more electrical power was generated than directly applying force to the PZT-stack, and 3) energy storage efficiency was significantly improved. In this paper, we are focusing on the investigations for the off-resonance mode performance of the PZT-Stacked-FEH through theoretical modeling, prototype development, and experimental studies. A prototype PZT-Stacked-FEH of weight 18 grams was able to generate 666 mW electrical power under 52 Nrms force at 250 Hz, which is much lower than the resonant frequency (936 Hz). At this condition, a 6,600 μF super-capacitor was charged from 0 to 7 V in 1.6 second, at an average rate of 100 mW. Furthermore, 70% of generated appear electrical powers were delivered to matched resistive loads in the investigated regime of frequencies. Finally, the experimental results matched well with theoretical predictions which verified the developed theoretical models.

A novel portable energy harvester using 3-3 mode piezoelectric stack with two-stage force amplification is proposed. It can obtain 21 times force amplification with 18% energy transmission ratio and generate electrical energy up to 79 times more than one piezoelectric ceramic of lead zirconate titanate (PZT) stack. Dynamic experiments demonstrate that the harvester with one-and two-stage force amplification can generate the maximum electrical power of 74.9 mW/g2 from one PZT stack at resonance frequency 235 Hz with matching resistance of 268 Ohms and 2642 mW/g2 from three PZT stacks at resonance frequency 37 Hz with match resistance of 1722 Ohm under 100 g proof mass and 0.1 g acceleration. Theoretical electromechanical modeling is established to reveal the working mechanism of force amplification and to predict electricity generation. Comparison of the predicted electricity with experimental results verified effectiveness of electromechanical modeling and optimization design methodology with consideration of tradeoff among force magnification ratio, energy transmission efficiency, and maximum stress. This piezoelectric energy harvester using two-stage force amplification can not only significantly improve power generation but also reduce the resonance frequency Moreover, the resonance frequency can also be adjusted by adjusting the mass load, by which a two-stage energy harvester can be applied to meet requirements of various bandwidths in low-frequency range.

This paper presents a material equivalent model, electromechanical coupling finite element (FE) modeling and experimental validation of a piezoelectric energy harvester for energy harvesting from human walking. The harvester comprises of six piezoelectric stacks within force amplification frames sandwiched between two heel-shaped aluminum plates, which can be put inside shoes as a shoe heel. The harvester amplifies the vertical dynamic reaction forces with ground at a heel and transfers them to the inner piezoelectric stacks to maximize the power output. Symmetries in geometry, load and boundary conditions are fully exploited and the multilayered piezoelectric stack is simplified as an equivalent bulk to simplify the FE model and expedite dynamic analysis. Dynamic simulation is performed on the symmetric FE model over different external resistive loads with the measured forces at different walking speeds as inputs. The prototype of the harvester is fabricated and tested on a treadmill to validate the proposed material equivalent model and FE model. The simulation results agree well with both the experimental measurements and numerical predictions from the simplified single degree-of-freedom (DOF) model. Parametric study is performed on the validated FE model to investigate the effect of geometric dimensions of the force amplification frames on the power output. The peak power outputs of 83.2 mW and 84.8 mW, and average power outputs of 8.5 mW and 9.3 mW are experimentally achieved at the walking speeds of 2.5 mph (4.0 km/h) and 3.0 mph (4.8 km/h), which agree well with the simulations. Simulation shows that an average power of 34.7 mW can be obtained at 6.0 mph (9.7 km/h).

To evaluate the clinical efficacy of puncturing Back-Shu acupoints for insomnia. Sixty patients were randomly divided into two groups, 30 cases in each. Back-Shu acupoints acupuncture was employed in the treatment group, whereas conventional acupoints acupuncture was administered in the control group. And the efficacy was assessed by the efficiency rate of relief of sleep disorders and the global Pittsburgh Sleep Quality Index (PSQI) score. The total effective rate was 93.3% in the treatment group, versus 80.0% in the control group, showing that the two groups were significantly different (P

Hexagonal boron nitride (h-BN) is traditionally considered to be insoluble in water. However, here we demonstrate that water is effective to exfoliate the layered h-BN structures with the assistance of bath sonication, forming “clean” aqueous dispersions of h-BN nanosheets without the use of surfactants or organic functionalization. Besides few-layered h-BN nanosheets, there was also evidence on the presence of monolayered nanosheet and nanoribbon species. Most nanosheets were of reduced lateral sizes, which was attributed to the cutting of parent h-BN sheets induced by the sonication-assisted hydrolysis (evidenced by the ammonia test and spectroscopy results). The hydrolysis effect also assisted in the exfoliation of h-BN nanosheets in addition to the solvent polarity effect. The h-BN nanosheets in such “clean” aqueous dispersions were demonstrated to be conveniently processed via solution methods with retained physical properties. The dispersed h-BN nanosheets in water also exhibited strong affinity tow...

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A series of poly(pyridinium triflate)s with alkyl and aromatic spacer groups were prepared by ring transformation polymerizations between various pyrylium triflates and diamines. The polymers are soluble in polar aprotic solvents and form tough, clear, flexible films. These novel polymers were characterized by IR, NMR, UV, DSC, TMA, and TGA. The polymers were thermally stable to 340 °C under nitrogen, and had softening points that ranged from 151 to 255 °C. Thin films were shown to display electrostrictive behavior in the presence of an applied electric field, with the amount of transverse strain being proportional to the concentration of charge in the polymer.

Bridge-type high- performance polymer micromachined actuators (PMATs) based on an electroactive polymer, modified poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer had been designed, modeled, fabricated, and characterized. The results show that the material enables the PMAT to exhibit a high stroke level (60 /spl mu/m displacement with 1 mm lateral dimension microactuator) with high-load capability and high-displacement voltage ratio (DVR) over a broad frequency range (>100 kHz). The stroke reduction in fluid (Silicone oil) is less than 5% comparing with the displacement in air. Impedance analysis and displacement measurement indicate that the PMAT has strong resonance behavior and the resonance frequency can be tuned by varying the dc bias field. Furthermore, the resonance peak, as expected by theoretical study, shifted to 6.5 times lower in fluid than in air with the mechanical Q value reduction less than 40%. In addition, the performance of the PMAT was modeled based on the elastic and electromechanical properties of the materials utilized in the PMAT and the configuration of the device. The comparison between the model and the experimental result shows a good agreement and validates the model as an effective method for the future development of PMAT for various applications. The high frequency response and respected performance in fluid medium demonstrate that the PMAT has potential for high performance MEMS components in the applications of microfluid systems, air dynamic control, under water transducers, and mass sensors, etc.

A micropump diaphragm, based on the high energy electron irradiated poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), an electroactive polymer (EAP), has been developed for air dynamic flow control. Its displacement stroke, profiles, and volume stroke rate (the volume change rate) have been characterized as a function of the electric field and the driving frequency. The displacement at the center of the diaphragm can reach 21 μm at 106 V/μm with the driving frequency of 10 Hz. The dispersion of the displacement is less than 30% for more than four frequency decades (0.1–1000 Hz). The characteristics of the electroactive polymer micropump diaphragm (EAPMPD) have also been theoretically evaluated. The volume rate of the EAPMPD can be 550 μL/min at 80 V/μm with the frequency of 1000 Hz. This study demonstrates that the volume rate of the diaphragm is high, and either the amplitude or the frequency of the applied electric field can tune it. In addition, when the performance of the diaphragm is modeled, the agreement between the theoretical results and the experimental data validates that the modeling provides an effective tool to guide EAPMPD design for an optimized performance. The results demonstrate that the diaphragm can be a candidate for aerospace applications to replace the traditional complex mechanical systems, increase the control capability, and reduce the weight for future air dynamic control systems.

A key, enabling element of a dielectric barrier discharge (DBD) actuator is the dielectric substrate material. While various investigators have studied the performance of different homogeneous materials, most often in the context of related DBD experiments, fundamental studies focused solely on the dielectric materials have received less attention. The purpose of this study was to conduct an experimental assessment of the body-force-generating performance of a wide range of dielectric materials in search of opportunities to improve DBD actuator performance. Materials studied included commonly available plastics and glasses as well as a custom-fabricated polyimide aerogel. Diagnostics included static induced thrust, electrical circuit parameters for 2D surface discharges and 1D volume discharges, and dielectric material properties. Lumped-parameter circuit simulations for the 1D case were conducted showing good correspondence to experimental data provided that stray capacitances are included. The effect of atmospheric humidity on DBD performance was studied showing a large influence on thrust. The main conclusion is that for homogeneous, dielectric materials at forcing voltages less than that required for streamer formation, the material chemical composition appears to have no effect on body force generation when actuator impedance is properly accounted for.

Two LiNbO3 (X and Y cut) crystals from different companies were implanted by 3.0 MeV Er ions to a dose of 7.5 x 10(14)ions/cm(2) and 3.5 x 10(14)ions/cm(2) with different beam current densities, respectively. After annealing at 1060 degreesC in air for 2 hours, one LiNbO3 sample was implanted by 1.5 MeV He ions to a dose of 1.5 x 10(16)ions/cm(2). The Rutherford backscattering/channeling and prism coupling method have been used to study the damage and optical properties in implanted LiNbO3. The results show: (1) the damage in LiNbO3 created by 3.0 MeV Er ions depends strongly on the beam current density; (2) after annealing at 1060 degreesC in air for 2 hours, a good Er doped LiNbO3 crystal was obtained; (3) there is waveguide formation possible in this Er-doped annealed LiNbO3 after 1.5 MeV He ion implantation. It is suggested that annealing is needed to remove the damage created by MeV Er ions before the MeV He ion implantation takes place, to realize the waveguide laser for Er doped LiNbO3.

Potassium titanyl phosphate (KTiOPO4 or KTP) was implanted by 3.0 MeV Er ions to a dose of 7.5×1014 ions cm−2 at room temperature. The damage in the as-implanted KTiOPO4 was studied by Rutherford backscattering/channeling. Photoluminescence (PL) measurement was performed at 10 K; the Er-implanted KTiOPO4 sample was annealed at 750°C for 20 min in a N2 atmosphere and then implanted by 2.8 MeV He ions to a dose of 1.5×1016 ions cm−2 at room temperature. The dark modes were measured by the prism coupling method. 14 dark modes were observed in KTiOPO4. The refractive index profile in the KTiPOP4 waveguide was theoretically analyzed. The result shows that the shape of the refractive index profile is similar to one of the nuclear energy loss distribution.

Electromechanical actuators that generate large displacements, have large load capabilities, and demonstrate strong resonance characteristics are in great demand in the areas of precision positioning, active vibration control, and energy harvesting. Piezoelectric materials have been widely investigated for these applications because of their high energy density, quick response time, and relatively low driving voltages, but they demonstrate very small strain, typically about 0.1%. We present experimental and finite element results for two designs that use active and passive frames, respectively, to enhance the small strain in piezoelectric multilayer stacks. The first design, stacked-HYBATS, employs the synergetic contribution of d33 and d31 mode piezoelectric material. Finite element results show that this structure can generate over 50 microns of displacement and nearly 40 N of blocking force in a 36 mm × 22 mm × 10 mm footprint. The second design employs frames made from passive materials to form two stages of strain amplification in a 42 mm × 30 mm × 20 mm footprint. This two-stage design can produce over 600 microns of displacement and has a blocking force of 27 N. The active and passive materials of both designs can be varied to maximize displacement and/or blocking force. The stacked-HYBATS and the two-stage amplification system display favorable force-displacement capabilities and are promising for a variety of manufacturing and space technology applications.Copyright © 2013 by ASME

The damage in Fe‐doped InP induced by 1.0 MeV P ion implantation with doses ranging from 5×1013 to 2×1015 cm−2 and effects of rapid thermal annealing (RTA) in the range of 700‐1050 °C were investigated by means of Raman scattering. The shift and asymmetrical broadening of the longitudinal optical phonon peak (LO) and the appearance of a transverse optical mode (TO) show that the Raman scattering is very sensitive to implantation damage. For doses larger than 5×1014 cm−2, the TO and LO peaks were markedly broadened, even merged into a single peak, indicating an amorphous structure in the near surface region. Much of the primary damage can be annealed out after RTA at 800 °C for all implantation doses. For RTA below 900 °C, the residual damage decreased with increasing annealing temperature for the low dose case of 1×1014 cm−2, but increased for the high dose case of 2×1015 cm−2. Only when the annealing temperature is over 900 °C, the residual defects of the high dose case drastically decrease, and nearly full recovery is obtained when the annealing temperature is raised to 1000–1050 °C.

A hybrid actuation system (HYBAS) utilizing advantages of a combination of electromechanical responses of an electrostrictive copolymer and an electroactive single crystal has been developed. The system employs the contributions of the actuation elements cooperatively. The theoretical modeling of the performances of the HYBAS is in good agreement with experimental observation. The consistency between the theoretical modeling and the experimental tests makes the design concept an effective route for tailoring and maximizing electrically driven displacement of the hybrid actuation system.

1.0 and 2.0 MeV Ti ions have been implanted into silicon at different angles to study longitudinal and transverse distributions. The profiles of implanted Ti ions in Si at different angles were measured by secondary ion mass spectrometry (SIMS). The longitudinal and transverse moments are compared with the TRIM'90 Monte Carlo simulation. The results show that the longitudinal moments-projected range and range straggling-are consistent with calculated values within 13% and 15% respectively and the transverse moment is in agreement with the TRIM'90 simulation within 29%. The depth distribution obtained is also compared to Gaussian and Pearson functions.

The rapid thermal annealing temperature dependence of solid phase epitaxial recrystallization and incorporation of Er-implanted silicon has been studied. It was observed that the initial recrystallization is epitaxial. followed by a disruption of regrowth in the doped region for the samples irradiated with 350 keV and 150 keV Er ions to doses of 1 x 10(15) cm(-2) and 7 x 10(14) cm(-2) respectively. The maximum incorporation concentration in the regrowth area for the former decreases with increasing annealing temperature. However, an anomalous enhancement of the maximum incorporation concentration is observed after annealing at 850 degrees C for the latter.

High energy (MeV) Cu ions were implanted into n‐type Si samples at angles of 7°, 30°, 45°, and 60°. The doses were 5×1014 and 2×1014 ions/cm2. The damage profiles in Si(100) were investigated by a Rutherford backscattering/channeling technique with 2.1 MeV He ions. The longitudinal damage straggling and lateral damage spread are estimated for 1.0 MeV Cu+ implanted in Si(100). The values obtained are compared with the trim (transport of ions in matter) code. The results show that the longitudinal damage straggling is found to be in good agreement with the calculated one within 13% by use of the trim code, but the experimental value of the lateral damage spread is higher than the calculated one by about 28% using the trim code. The effect of dose rate, energy, and dose on damage distribution is investigated also.

Defect distributions in Si created by high energy MeV Ti ions were studied as a function of the irradiation angle and energy using Rutherford backscattering/channeling. A silicon crystal of 〈100〉 direction was irradiated at room temperature by 1.0–2.0 MeV Ti ions under tilted angles with a dose of 5 × 10 14 ions cm −2 . It is found that the damage peak produced by 1.0 MeV Ti + is higher than one produced by 2.0 MeV Ti + at the same dose. The defect distributions extracted from the present experiment are compared with TRIM '89 calculations. The results show that the shape and depth of the damage profile under tilted angle implantation are qualitatively describe by TRIM '89.

The rapid thermal annealing temperature dependence of the recrystallization, Yb migration and its optical activation were studied for Yb-implanted silicon. For the annealing regime 800-1000-degrees-C, the Yb segregates both at the crystal/amorphous interface and at the surface, which is different from the usual segregation of Er at the crystal/amorphous interface, and the efficiency of optical activation also increases with annealing temperature. However, the amorphous layer regrows completely and no photoluminescence is observed after the annealing at 1200-degrees-C.

In this paper, we report the study of a “33” longitudinal mode, piezoelectric PZT ceramic multilayer stack (PZT-Stack) with high effective piezoelectric coefficient for broader bandwidth high-performance piezoelectric energy harvesting transducers (PEHTs). The PZT-Stack is composed of 300 layers of 0.1 mm thick PZT plates, with overall dimensions of 32.4 mm × 7.0 mm × 7.0 mm. Experiments were carried out with dynamic forces in a broad bandwidth ranging from 0.5 Hz to 25 kHz. The measured results show that the effective piezoelectric coefficients (EPC, deff ) of the PZT-stack is about 1 × 105 pC/N at off-resonance frequencies and 1.39 × 106 pC/N at resonance, which is order of magnitude larger than that of traditional PEHTs. The EPC do not change significantly with applied dynamic forces having root mean square (RMS) values ranging from 1 N to 40 N. In resonance mode, 231 mW of electrical power was harvested at 2,479 Hz with a dynamic force of 11.6 Nrms , and 7.6 mW of electrical power was generated at a frequency of 2,114 Hz with 1 Nrms dynamic force. In off-resonance mode, an electrical power of 18.7 mW was obtained at 680 Hz with a 40 Nrms dynamic force. A theoretical model of energy harvesting for the PZT-Stack was established. The modeled results matched well with experimental measurements. This study demonstrated that structures with high EPC enable PEHTs to harvest more electrical energy from mechanical vibrations or motions, suggesting an effective design for high-performance low-profile PEHTs with potential applications in military, aerospace, and portable electronics. In addition, this study provides a route for using piezoelectric multilayer stacks for active or semi-active adaptive control to damp, harvest or transform unwanted vibrations into useful electrical energy.Copyright © 2011 by ASME

X, Y, and Z crystalline cut LiNbO3 crystals were implanted by 1.0 MeV F ions with a dose of 1×1015 ions/cm.2 The virgin and implanted LiNbO3 crystals were investigated using the Rutherford backscattering/channeling technique. The obtained minimum yields of virgin crystals were 4%, 8%, and 6% for X‐, Y‐, and Z‐cut LiNbO3 crystals, respectively, because of their different arrangements of lattice sites in channeling direction. The measured damage profiles are also influenced by the arrangement of lattice sites in channeling measurements. The damage profiles of X‐cut LiNbO3 crystal induced by 1.0 MeV F+ at a fluence range of 1×1014–3×1015 ions/cm2 have been studied and compared with the Transport of Ions in Matter, version 1990 calculation. It has been found that not only the nuclear energy deposition but also the electronic energy deposition influences the defect production.

A carbon nanocomposite-based contact mode interdigitated center of pressure sensor (CMIPS) has been developed. The experimental study demonstrated that the CMIPS has the capability to measure the overall pressure as well as the center of pressure in one dimension, simultaneously. A theoretical model for the CMIPS is established here based on the equivalent circuit of the CMIPS configuration as well as the material properties of the sensor. The experimental results match well with the theoretical modeling predictions. This theoretical model will provide guidelines for future advanced sensor development based on the CMIPS. A system mapped with two or more pieces of the CMIPS can be used to obtain information from the pressure distribution in multi-dimensions. As an intelligent system component, the inexpensive CMIPS can be used broadly for improving sensing and control capabilities of aircraft and measurement capabilities of biomedical research as well as chemical industries.

The effects of 1 MeV Cu ion implantation in LiNbO3 crystals have been investigated using the Rutherford backscattering/channeling technique. The samples have been implanted with doses ranging from 5×1014 ions/cm2 to 2×1015 ions/cm2. The damage profiles have been deconvoluted from Rutherford backscattering spectra after considering the energy spreading due to difference of stopping power between nonchanneled and channeled particles. The energy dependence of the scattering cross section and stopping power have also been taken into account. The damage profiles have compared with TRIM’89 (Transport of Ions in Matter, version 1989) code calculation. For the lowest dose (5×1014 ions/cm2) implantation, the damage profile is in agreement with the defect profile calculated using the trim code. The damage peak is located shallower than the theoretical ion mean projected range, but the damage spread is larger than the ion spread. For higher dose implantations, a broadening of the damage profiles is observed, probabl...

P-type silicon crystal has been irradiated at room temperature by 1.0 MeV Ti ions at tilted angle incidence in order to study the damage profiles. The irradiation was performed to a dose of 5×10 14 ions/cm 2 under different tilted angles: 7°, 30°, 45° and 60°. The Rutherford backscattering (RBS)/channeling technique of 2.1 MeV He ions has been used in order to obtain information on the damage profiles. The damage profiles extracted are compared with the transport of ions in matter (TRIM'89). The result shows that the damage profiles seem to be in good agreement with the TRIM'89 prediction.

A new configuration of an electroactive polymer, ceramic-based micro hybrid actuation system (μHYBAS) is proposed in this paper. The μHYBAS is a device concept to utilize different electroactive materials in a cooperative and efficient method for optimized electromechanical performance. A theoretical model has been developed, based on the elastic and electromechanical properties of the materials and on the configuration of the device. The μHYBASs investigated use piezoelectric polyvinylidene fluoride (PVDF) as the electroactive polymer (EAP) element combined with the electroactive ceramic (EAC) elements, which are piezoelectric hard lead zirconate titanate (PZT), soft PZT, or Pb(Zn 1/3 Nb 2/3 )O 3 -4.5%PbTiO 3 single crystal (PZN-PT single crystal). The μHYBAS demonstrates significantly enhanced electromechanical performance by utilizing advantages of synergistic contributions of the electromechanical responses of an electroactive polymer and an electroactive ceramic. The modeled results provide guidelines for future developments of high performance μHYBASs to meet various applications.

An electroactive polymer (EAP)-ceramic hybrid actuation system (HYBAS) was developed recently at NASA Langley Research Center. This paper focuses on the effect of the bending stiffness of the EAP component on the performance of a HYBAS, in which the actuation of the EAP element can match the theoretical prediction at various length/thickness ratios for a constant elastic modulus of the EAP component. The effects on the bending stiffness of the elastic modulus and length/thickness ratio of the EAP component were studied. A critical bending stiffness to keep the actuation of the EAP element suitable for a rigid beam theory-based modeling was found for electron irradiated P(VDF-TrFE) copolymer. For example, the agreement of experimental data and theoretical modeling for a HYBAS with the length/thickness ratio of EAP element at 375 times is demonstrated. However, the beam based theoretical modeling becomes invalid (i.e., the profile of the HYBAS movement does not follow the prediction of theoretical modeling) when the bending stiffness is lower than a critical value.

As previously reported, a NASA Langley-developed electroactive polymer-ceramic hybrid system (HYBAS) has demonstrated significant enhancement in actuating displacement. The displacement of the system is derived from both the electrostrictive polymer and from single crystal elements. The electroactive elements are driven by a single power source. Recently, a modification of HYBAS has been made to increase the capability of air driving for synthetic jet devices (SJ) used in aerodynamic control technologies. The dependence of the air driving capability of the modified HYBAS on the configuration of the actuating device has been investigated. For this particular application, the modified HYBAS demonstrated a 50% increase in the volume change in the synthetic jet air chamber, as compared with that of the HYBAS without the modification.

Piezoelectric lead magnesium niobate-lead titanate (PMN-PT) single crystal is one of the most promising materials for electromechanical device applications due to its high electrical field induced strain and high electromechanical coupling factor. PMN-PT single crystal-based multilayer stack actuators and multilayer stack-based flextensional actuators have exhibited high stroke and high displacement-voltage ratios. The actuation capabilities of these two actuators were evaluated using a newly developed method based upon a laser vibrometer system under various loading conditions. The measured displacements as a function of mechanical loads at different driving voltages indicate that the displacement response of the actuators is approximately constant under broad ranges of mechanical load. The load capabilities of these PMN-PT single crystal-based actuators and the advantages of the capability for applications will be discussed.

An electroactive polymer (EAP), high energy electron irradiated poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer, based actuation micropump diaphragm (PAMPD) has been developed for air flow control. The displacement strokes and profiles as a function of amplifier and frequency of electric field have been characterized. The volume stroke rates (volume rate) as function of electric field, driving frequency have been theoretically evaluated, too. The PAMPD exhibits high volume rate. It is easily tuned with varying of either amplitude or frequency of the applied electric field. In addition, the performance of the diaphragms were modeled and the agreement between the modeling results and experimental data confirms that the response of the diaphragms follow the design parameters. The results demonstrated that the diaphragm can fit some future aerospace applications to replace the traditional complex mechanical systems, increase the control capability and reduce the weight of the future air dynamic control systems.

An electroactive polymer-ceramic hybrid actuation system (HYBAS) was recently developed. The HYBAS demonstrates significantly-enhanced electromechanical performance by utilizing advantages of cooperative contributions of the electromechanical responses of an electrostrictive copolymer and an electroactive single crystal. The hybrid actuation system provides not only a new type of device but also a concept to utilize different electroactive materials in a cooperative and efficient method for optimized electromechanical performance. In order to develop an effective procedure to optimize the performance of a hybrid actuation system (HYBAS), a theoretical model has been developed, based on the elastic and electromechanical properties of the materials utilized in the system and on the configuration of the device. The model also evaluates performance optimization as a function of geometric parameters, including the length of the HYBAS and the thickness ratios of the constituent components. The comparison between the model and the experimental results shows a good agreement and validates the model as an effective method for the further development of high performance actuating devices or systems for various applications.Copyright © 2004 by ASME

The electrostrictive graft elastomer is a new type of electromechanically active polymer developed by NASA. The material has demonstrated promising electromechanical properties including large electrical field induced strain, high electromechanical output, and a relatively high mechanical modulus. As a two-component system, the elastomer contains flexible backbone chains and electro-responsive polar grafted crystal domains. The two-component material system enables optimization of the electrostriction by controlling the relative fraction of the two components and the molecular morphology. The present work is a systematic study on the effects of the relative fraction of the two components and morphology on the electrical field induced strain. The results show that the elastomer containing more polar grafted domains and higher crystallinity yields higher electric field-induced strains.

Electroactive polymers (EAP) demonstrate advantages over some traditional electroactive materials such as electro-ceramics and magneostrictive materials for electromechanical device applications due to their high strain, light weight, flexibility, and low cost. Electroactive polymer-based microelectromechanical systems (EAP-MEMS) are increasingly demanded in many aerospace and medical applications. This paper will briefly review recent progress in the developments and applications of EAP- MEMS. In the past few years, several new configurations of micromachined actuators/transducers have been developed using electroactive polymers. The performance of these micromachined EAP-based devices has been evaluated for both fluid and air conditions. The performance of EAP-MEMS has also been theoretically modeled based on material properties and device configurations. In general, the results obtained from modeling agree with the experimental measurements. Critical process issues, including patterned micro-scale electrodes, molded micro/nano electroactive polymer structures, polymer to electrode adhesion and the development of conductive polymers for electrodes will be discussed. The challenges to develop complete polymer MEMS will also be addressed.