Piezoelectric sensor

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

Broadband piezoelectric shunts for passive structural vibration control

Abstract: This paper reports an advanced passive piezoelectric shunt damping technique called broadband piezoelectric shunting. The shunt circuit for the broadband shunting is built with a reactance neutralizing circuit, which is designed with operational amplifier circuits to maximize the parallel reactance of the shunt circuit over a wide frequency band. It is different from the earlier shunt circuits, either used for the single- or multiple-mode shunting, which were built with inductors or simulated inductor circuits. In these earlier shunt circuits the anti-resonant frequency of the shunt circuit, with the inclusion of the piezoelectric transducer, was tuned with the inductor to a specific frequency to match with the natural frequency of the mode to be controlled. We first describe how the concept of the broadband shunt circuit was conceived and developed. We next report the shunt damping experiments performed on three difference structures: a thin aluminum cantilever beam, a two-wing aluminum cantilever beam, and a small-scale thermoplastic composite fairing. We have successfully demonstrated broadband amplitude reduction of structural vibration modes over a wide frequency band using the broadband shunt-damping technique. More detailed experimental results will be presented.

Electric poling and electromechanical characterization of 0.1-mm-thick sensor films and 0.2-mm-thick cable layers from poly(Vinylidene Fluoride-Trifluroethylene)

Abstract: Piezoelectric polymers have been proposed for many sensor and actuator applications. Among these, piezoelectric polymer films with thicknesses between several tens and a few hundreds of micrometers as well as coaxial cables with piezoelectric polymer layers are highly suitable and attractive for the detection of mechanical loads. In addition to good piezoelectric properties, materials for such sensors should have high mechanical strength. Therefore, the most common materials are nonporous piezoelectric polymers, such as polyvinylidene fluoride (PVDF) or its copolymer with trifluoroethylene (P(VDF-TrFE)). Here, P(VDF-TrFE) polymer films as well as the operating principle and the geometry of piezoelectric polymer cables are described. As active piezoelectric cable layer, P(VDF-TrFE) (76/24) was employed. After electrical poling with one or more point-to-cable corona discharges, the polarization in the P(VDF-TrFE) layer was investigated. Poling parameters, such as electric field and poling time, were varied. The resulting polarization was characterized with measurements of polarization profiles across the film or the cable-layer thickness as well as with the determination of other electromechanical quantities. The optimized poling process yields good piezoelectric properties in the piezoelectric polymer layers as well as useful sensor properties of the piezoelectric polymer cable, which are assessed and discussed.

Mixed piezoelectric plate elements with direct evaluation of transverse electric displacement

Abstract: A mixed variational statement for the analysis of layered structures under the effect of mechanical and electrical fields is proposed in this paper to develop finite plate elements that permit the direct evaluation of transverse electrical displacement Dz. The original Reissner mixed variational theorem, RMVT, has been modified to account for 'only' interlaminar continuous Dz. Continuity of mechanical variables, such as transverse shear and normal stress components, has been discarded to provide a simple 'electrical' modified RMVT, here called RMVT-Dz. Finite element implementations are made via the Carrera unified formulation. The advantages of the proposed approach have been demonstrated through numerical comparisons with classical formulations based on the principle of virtual displacements as well as with available 3D solutions.

Micro-mechanical device, micro-switch, variable capacitor high frequency circuit and optical switch

Abstract: A micro-mechanical device includes a first piezoelectric actuator including a piezoelectric film, and lower and upper electrodes interleaving the piezoelectric film, and extending from a first fixing part on a substrate to a first operating end, and a second piezoelectric actuator connected to the first piezoelectric actuator via a connecting part at the first operating end of the first piezoelectric actuator, and extending from the connecting part to a second operating end, the second piezoelectric actuator being shorter than the first piezoelectric actuator.

Dynamic characterization of piezoelectric paint sensors under biaxial strain

Abstract: A piezoelectric paint film has been designed to be used as a strain sensor. The composite is a suspension of milled lead zirconate titanate (PZT) ceramic powder in a polymer binder (water-based acrylic). The sensitivity of the sensor was estimated as the electric displacement (electric charge per electrode area) generated by the sensor relative to the strain experienced by the substrate surface, under the hypothesis that the electric charge generated is proportional to the sum of the principal strains. The piezoelectric constant d31 (conventionally used to characterize piezoelectric sensor materials for structural vibration measurement) has also been obtained. The sensor linearity has been demonstrated over a strain range of ±200 μɛ and the sensor sensitivity is shown to be flat to within ±2 dB over a frequency range of 5–500 Hz, ranges typically required for structural vibration monitoring applications.