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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 13 of 13 for “"Piezoceramics"”.
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A demonstration of useful electric energy generation from piezoceramics in a shoe
The feasibility of harnessing electric energy using piezoelectric inserts in a sport sneaker has been demonstrated. Continuing in that spirit, this thesis compares regulation schemes for conditioning the electric energy harnessed by a piezoceramic source imbedded in a shoe insole. Two off-line, …
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A Comprehensive Experimental Evaluation of Actively Controlled Piezoceramics with Positive Posistion Feedback for Structural Damping
… the effectiveness of actively controlled piezoceramics with positive position feedback (PPF) for reducing structural vibrations. A comparison is made between active control with PPF and a parallel resistor-inductor (RLC) shunt technique. The primary objectives of this study are to: 1. …
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Modeling of materials with internal variables using a thermomechanical approach
… and a one-dimensional constitutive model for piezoceramics have been developed, respectively. In modeling the two-way shape memory effect, a residual stress σ<sub>re</sub> is introduced as a controlling parameter for the two-way shape memory effect. A further refinement of the transformation …
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Design of an active compressor blade for aeroelastic studies
… ranges, but the strain predictions on the piezoceramics were near the ultimate. The composite spar modeling and piezoelectric actuation modeling were verified with experimental results. The piezoceramics were protected from large tensile strains by bonding to the composite with a …
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Performance Modeling and Efficiency Analysis for a Piezohydraulic Pump with Active Valves
… advantage of the high force capabilities that piezoceramics have and combines it with the operation at high frequencies, in order to achieve the hydraulic actuation of a system under a specified stroke and force. In this research, a compact piezohydraulic pump with active valves has been …
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Electromechanical Modeling of Piezoelectric Energy Harvesters
… performances of commonly used monolithic piezoceramics and novel single crystals with a focus on the effects of plane-stress material constants and mechanical damping. The effects of strain nodes and electrode configuration on piezoelectric energy harvesting are discussed theoretically and …
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Enhanced biopsy and regional anaesthesia through ultrasound actuation of a standard needle
… shown the potential to replace the conventional piezoceramics in high power and actuator applications. Moreover, the d31-mode based planar cutting tool contrasts with the cumbersome design of mass-spring transducer structure and has the potential to be used in surgical procedures. <br/>
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Development and Analysis of the Lumped Parameter Model of a Piezo-Hydraulic Actuator
… advantage of the high force capabilities that piezoceramics have and combines it with the operation at high frequencies, in order to achieve the hydraulic actuation of a system under a specified stroke and force. High frequency rectification translates the low stroke of a piezoelectric stack …
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Materials selection for microsystems actuators
… thickness for an optimal performance. Pb based piezoceramics on Si/DLC substrates are promising for high force piezoelectric MEMS actuators. Piezoelectric actuators operate at mechanical resonance (> 100 kHz) and hence the achievable frequencies are greater than that of the electrothermal …
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Piezoceramic Actuated Transducers for Interior Acoustic Noise Control
… a sensor or an actuator due to the nature of the piezoceramics. The sound absorbing transducer is modeled to couple to the first acoustic resonance of a six foot cylindrical cavity. The cavity acts as a simplified model of a launch vehicle payload fairing. Equations of motion are derived to model …
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Piezohydraulic Actuator Design and Modeling Using a Lumped-Parameter Approach
… the reciprocal small stroke displacement of piezoceramics into unidirectional motion by frequency rectification through a hydraulic fluid. It takes advantage of the high force capabilities that piezoelectric materials have and couples it with very stiff media such as hydraulic fluid to …
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Vibration Suppression Using Smart Materials in the Presence of Temperature Changes
Aircraft and satellite structures are exposed to a wide range of temperatures during normal operation cycles. These fluctuations in temperature may result in significant changes of the structural dynamics. Aircraft, automotive, and satellite structures are also subject to various vibration sources. …