A study of time harmonic guided Lamb waves and their caustics in composite plates.

Spatial steady-state Lamb wave propagation in an anisotropic composite plate excited by harmonic surface sources is modeled using a Green's matrix representation in a frequency-wavenumber domain. An approach based on a residue integration technique for two dimensional wavenumber integrals for the computation of displacements outside an excitation source is presented in this paper. In the far-field zone of the excitation source, the method of stationary phase is used, which gives an asymptotic expansion of the displacement vector as a sum of cylindrical waves.

Investigation of Lamb elastic waves in anisotropic multilayered composites applying the Green's matrix.

This article presents a numerical study of dispersion characteristics of some symmetric and antisymmetric composites modelled as multilayered packets of layers with arbitrary anisotropy of each layer. The authors introduce a subsidiary boundary problem of three-dimensional elasticity theory for the system of partial differential equations describing the harmonic oscillations of the composite caused by a surface load. The problem reduces to a boundary problem for ordinary differential equations by employing the Fourier transform.

Development and analysis of a longitudinal and torsional type ultrasonic motor with two stators.

In this paper, a new longitudinal and torsional type ultrasonic motor with two stators is presented and investigated. Normally, such a motor consists of one rotor and one stator, and two types of transducers that are longitudinal PZT and torsional PZT are used to generate the desired elliptical locus on the stator surface. The operating frequency is at the resonance frequency of torsional transducer.