I would like to describe some of our programs at NASA, Langley Research Center, Hampton, VA, on the development and use of a new type of phase insensitive transducer we call an Acoustoelectric Converter, or an AEC. In the very short time I have here, I shall indicate why the AEC is significant and show some ultrasonic transmission results obtained from modified isometric attentuation scans of c...

Abstract A non-resonant piezoelectric sensor for measuring power-frequency (50 Hz or 60 Hz) electric currents is proposed to be applied in power systems. The device consists of a magnetic circuit, two plates, and fixed plates. circuit made up three NdFeB magnets permalloy yokes. high sensitivity the attributed field concentration induced shear stresses. prototype has been fabricated feasibility...

This paper presents a new finite modelling of the nonlinear static bending analysis piezoelectric functionally graded (FG) sandwich plates resting on elastic foundations. Finite element formulations are derived by using first-order shear deformation theory (FSDT) Mindlin and method. The proposed mathematical model this work verified comparing results with those other methods, they in good agree...

There is evidence to support the claim that speedbreakers can cause accidents and injury. When a vehicle approaches a speed-breaker at a speed greater than some threshold velocity, the risk of accident or injury is substantial. Speed-breakers are inconspicuous in low visibility conditions, like at night, or when there is fog, rain or snow. This problem is particularly acute in developing countr...

A variety of Lamb wave methods have been shown to be effective in localizing damage in homogeneous plates. However, many structural components of interest are not simple plates of constant thickness, but are plate-like in geometry with inhomogeneities present in the form of thickness variations. Here we consider aluminum plates with thickness transitions typical of realistic structures. A spars...

Periodic arrays of shunted, piezoelectric patches are employed to control waves propagating over the surface of plate structures, and corresponding vibrations. The shunted, piezoelectric patches act as sources of impedance mismatch, which gives rise to interference phenomena resulting from the interaction between incident, reflected and transmitted waves. Periodically distributed mismatch zones...

Lead zirconate titanate (PZT) ceramics is usually used as a piezoelectric material. However it has characteristics of not only piezoelectricity but also flexoelectricity. Piezoelectricity is a phenomenon that electric polarization is induced by strain, and flexoelectricity is the one that the polarization is induced by strain gradient. In this study, flexoelectricity in poled soft PZT ceramics ...

Starting from the general modal solutions for a homogeneous layer of arbitrary material and crystalline symmetry, a matrix formalism is developed to establish the semianalytical expressions of the surface impedance matrices (SIM) for a single piezoelectric layer. By applying the electrical boundary conditions, the layer impedance matrix is reduced to a unified elastic form whether the material ...

In order to quantify the wave motion of guided ultrasonic waves, the characteristics of piezoelectric detectors, or ultrasonic transducers and acoustic emission sensors, have been evaluated systematically. Such guided waves are widely used in structural health monitoring and nondestructive evaluation, but methods of calibrating piezoelectric detectors have been inadequate. This study relied on ...

Surface micro-structuring of silica glass plates was performed by using laser-induced backside wet etching (LIBWE) upon irradiation with a single-mode laser beam from a diode-pumped solidstate UV laser at 266 nm. We have succeeded in a well-defined micro-pattern formation without debris and microcrack formations around the etched area on the basis of galvanometer-based point scanning system wit...