Elastic parameters characterization of multilayered structures by air-coupled ultrasonic transmission and genetic algorithm.

This paper describes a non-contact method to characterize isotropic and anisotropic planar multilayer structures using a genetic algorithm. The method is based on the determination of critical angles, where the maxima of the modulus of transmission coefficient of the structure appear, and which correspond to the generation of guided waves. The optimization process minimizes the error between the reference critical angles and associated amplitudes of the transmission coefficient, with the corresponding estimated ones.

Modeling of the Electromechanical Behavior of Barium Titanate Under Mechanical Stress and Comparison With Experimental Measurements.

Barium titanate (BaTiO) is increasingly studied to replace lead-based piezoelectric materials, such as those which belong to the lead zirconate titanate (PZT) family, due to lead toxicity. In many applications, such as Tonpilz transducers, piezoelectric materials undergo mechanical stress simulation of which is important to control and predict electroacoustic effects. Thus, this article deals with a fully tensorial model that allows to simulate the behaviors of electrical displacements and elastic strains under mechanical stress.

Modeling and numerical study of the influence of imperfect interface properties on the reflection coefficient for isotropic multilayered structures.

The microelectronics industry is expressing an increased demand for the development of non-destructive tools and methods for health control and diagnostics in multilayered structures. The purpose of these tools is to detect problems such as delaminations, inclusions and microcracks. The aim of this paper is to study the effect of imperfect interfaces on the wave propagation in multilayered structures.

Electromechanical Behavior of a Doped Barium Titanate Piezoceramic Under Mechanical Stress: Modeling and Comparison With Experimental Measurements.

Barium titanate (BaTiO) is being studied extensively to replace lead-based piezoelectric materials, such as the lead zirconate titanate (PZT) family, due to lead toxicity. As a result, researchers are turning to materials such as BaTiO and seek to improve their properties with the use of dopants. In many applications such as Tonpilz transducers, piezoelectric materials undergo mechanical stress which is important to control and predict their electro-acoustic performance.

Internal Electric Field in Co-Doped BaTiO With Co, Nb, Li, and F: Impact on Functional Properties and Charge Compensation With Niobium and Fluorine Ions.

Dense barium titanate (BaTiO) ceramics ( [Formula: see text]) with a microscale grain size are obtained at 800 °C-1100 °C by a solid-state ceramic process. BaTiO (BT) doped with Co leads to a significant improvement in the properties ( pC/N). Soft and hard characteristics of the piezoceramics are observed depending on the dopant ions.