Piezoelectric sensor

About: Piezoelectric sensor is a research topic. Over the lifetime, 7127 publications have been published within this topic receiving 115903 citations.

Active Damping of Thermally Induced Vibrations

Abstract: The prospect of using active damping in a smart structure to suppress thermally induced vibration is investigated. Here smart structure refers to an aluminum structure with an integrated active control system consisting of piezoceramic sensors and actuators. A simply supported aluminum beam is used to illustrate the nature of thermally induced vibrations caused by a suddenly applied heat flux. A distributed piezoelectric self-sensing sensor/actuator pair is implemented to actively suppress the motion caused by thermal disturbances. The effect of large temperature changes on the structure and actuator are taken into account in the control system design. A proportional-derivative controller, a linear quadratic regulator and a positive position feedback filter are considered. Simulation results show that thermally induced vibrations can be damped using currently available smart structure technology, provided temperature effects are properly accounted for in the control law.

Trailing edge acoustic emission sensor and pyroelectric sensor for asperity detection

Abstract: A disc testing system includes a base, a disc rotatably attached to the base, and an actuator assembly movably attached to the base. A ramp assembly includes a set of ramps for loading and unloading the sliders and transducing elements carried by the sliders to and from the disc attached to the base. A load spring is attached to the arm of the actuator. A slider is attached to the load spring. The slider further includes a leading edge and a trailing edge. A piezoelectric sensor and a pyroelectric sensor is carried by the trailing edge of the slider. The piezoelectric sensor and the pyroelectric sensor are made from the same material which has both piezoelectric properties and pyroelectric properties. The piezoelectric sensor and the pyroelectric sensor are formed by the same process. The two sensors can also be formed substantially simultaneously. A conductive layer is placed on the trailing edge of the slider followed by a strip of thick film material. Epoxy may be added to the sensors to form a composite of epoxy and lead titanate zirconate.

Measurement of density and viscoelasticity with a single acoustic wave sensor

Abstract: A sensor, method and system, for measuring certain characteristics of a fluid. The sensor utilizes a piezoelectric device having at least two tightly coupled resonators providing a two pole electric transfer function responsive to an electrical signal coupled to the input resonator. The piezoelectric sensor has a textured entrapment layer, constructed to entrap a known volume of fluid and impart motion to the entrapped fluid as well as to surrounding non-trapped fluid. The common mode frequency shift of the two resonant frequencies is related to mass loading due to the entrapped fluid, while the energy absorbed by the fluid, or a phase shift of one of the resonant frequencies, is related to the viscosity/density product of the fluid. Extracting the viscosity is a matter of mathematical manipulation. By controlling the energy level of the input electrical signal, the viscosity measurement may be conducted at a predetermined shear rate.

Finite-element simulation of closed loop vibration control of a smart plate under transient loading

Abstract: A plate structure with integrated piezoelectric patches is modeled using the finite-element method which is based on a combination of three-dimensional piezoelectric, flat shell and transition elements. Constant velocity and constant displacement feedback control algorithms are used to actively control the dynamic response of the integrated smart structure through closed loop control. A modal superposition technique coupled with a direct integration method (α-method) is used in the numerical simulation to calculate the dynamic response of the system. In this work, the performance of the active controller for vibration suppression is demonstrated for a clamped plate with piezoelectric patches glued in pairs on both sides of the plate. By using strategically located sensor/actuator pairs, several modes of a clamped square plate are successfully controlled. The control effectiveness of the actuators is maximized by locating them at points of maximum strain in the frequency and time domains. We conclude that discrete sensor/actuator devices are to be preferred over distributed piezoelectric films to realize lower weight and effective control authority for modest values of actuator voltages for active vibration control of practical structures.

On the design of piezoelectric smart fins for flight vehicles

Abstract: A systematic approach for the design of active piezoelectric fins developed for a small-scale flight vehicle is presented. The proposed design approach uses analytical and computational tools that are based on the high-order theory and provides a graphical representation of the response spectrum of the active fin. In addition, it enables the coupling of the structural and aerodynamic analyses and provides a frame in which the results of the two types of analysis are adjoined. A numerical design study of a twist-actuated smart fin is presented and discussed. The results reveal the sensitivity of the structure to a broad range of geometrical, mechanical, and electromechanical design variables and provide guidelines for the optimization of the active structure. A set of normalized design master curves that can be scaled to fit various geometrical layouts of the structure investigated are also presented and discussed.