Piezoelectric sensor

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

Method and apparatus for measuring viscosity in a liquid utilizing a piezoelectric sensor

Abstract: A piezoelectric element energized to exhibit thickness-shear mode vibration is utilized to measure the viscosity of liquids. Electrodes, of an inert material are bonded to the major faces of the disc shaped crystal and are of a lesser diameter than the crystal surfaces so as to provide a concentric ring area of the crystal that is unenergized.

Experimental investigation of composite beams with piezoelectric actuation and debonding

Abstract: Piezoelectric transducers can be used as sensors and actuators for vibration reduction in composite structures. Debonding at the transducer-laminate interface results in significant changes to the dynamic response and control authority. This important issue is studied in the current work. Composite specimens with surface bonded piezoelectric transducers were constructed with varying stacking sequences and debonding lengths. Closed loop control was implemented using an analog circuit. Experimental results were obtained for both open and closed loop frequencies and damping ratios. The results correlate well with a newly developed higher order based theory for modeling composites with debonded piezoelectric transducers. Significant changes are observed in the open and closed loop frequencies and damping ratios as a result of debonding.

Coupled Thermo-Piezoelectric-Mechanical Model for Smart Composite Laminates

Abstract: A coupled thermo ‐piezoelectric ‐mechanical model of composite laminates with surface bonded piezoelectric actuators, subjected to externally applied loads, isdeveloped. The governing differential equationsare obtained by applying the principleof freeenergy and variational techniques. A higher-order displacement e eld is used to accuratelycapturethetransversesheareffectsinlaminatedcompositeplatesofarbitrarythickness.Adoubletriangular function expansion that satise es the boundary conditions is used as a solution. Both thermal and mechanical loads are considered, and the effect of actuation is studied. Composite laminates of various thickness and lengths are analyzed.Thethermalcouplingisshowntohavesignie canteffectsinbothquasi-staticandactiveresponseanalyses. Nomenclature aT = cE=T0 bij = dielectric permittivity cE = heat capacity cijkl = elastic constants Di = electric displacement vector di = thermal‐piezoelectric coupling constants Ei = electric e eld eijk = piezoelectric constants kij = thermal‐mechanical coupling constants L1 = displacement operator matrix L2 = piezoelectric operator matrix l1 = thermal operator vector N1

Piezoelectric device and process for production thereof

Abstract: A sheet-form piezoelectric device having improved mechanical strengths as represented by an electrode peel strength while retaining flexibility and piezoelectric performances of a polymer-type piezoelectric device, is obtained by embedding a perforated sheet electrode into at least one surface layer of a polymer piezoelectric film treated with a solvent in advance. The sheet-form piezoelectric device may be wound or curved about a certain central axis to provide a tubular or curved piezoelectric device having wave-transmitting and/or -receiving characteristics suitable for wave-transmitting and/or -receiving devices, such as a hydrophone and microphone.

Distributed Piezoelectric Sensor System for Damage Identification in Structures Subjected to Temperature Changes.

Abstract: Structural health monitoring (SHM) is a very important area in a wide spectrum of fields and engineering applications. With an SHM system, it is possible to reduce the number of non-necessary inspection tasks, the associated risk and the maintenance cost in a wide range of structures during their lifetime. One of the problems in the detection and classification of damage are the constant changes in the operational and environmental conditions. Small changes of these conditions can be considered by the SHM system as damage even though the structure is healthy. Several applications for monitoring of structures have been developed and reported in the literature, and some of them include temperature compensation techniques. In real applications, however, digital processing technologies have proven their value by: (i) offering a very interesting way to acquire information from the structures under test; (ii) applying methodologies to provide a robust analysis; and (iii) performing a damage identification with a practical useful accuracy. This work shows the implementation of an SHM system based on the use of piezoelectric (PZT) sensors for inspecting a structure subjected to temperature changes. The methodology includes the use of multivariate analysis, sensor data fusion and machine learning approaches. The methodology is tested and evaluated with aluminum and composite structures that are subjected to temperature variations. Results show that damage can be detected and classified in all of the cases in spite of the temperature changes.