Ultrasonic guided wave energy behavior in laminated anisotropic plates

Abstract

A Gaussian beam model coupled with the transfer-matrix technique, was employed to obtain the internal distributions of the energy vector (also called as power density vector or Poynting vectors) of guided ultrasonic plate waves that are modified due to the anisotropy of the media. The spatial pattern of the energy partitioning of the ultrasonic guided waves, previously called plate-wave-flow-patterns, was predicted from the material properties. The model-based predictions of the plate wave flow patterns in fiber reinforced graphite-epoxy laminates, in the form of gray scale images, compared well with the experimental results. In particular, the observed feature that guided waves in plates with structure-induced anisotropy, such as fiber-reinforced composites, tend to follow preferred directions, is predicted by the model. The model provides further insight into the understanding of the generation and propagation of guided wave mode patterns in structure-induced anisotropic plates. Such studies have potential for application in the area of acoustic emission monitoring, structural health monitoring, and stealth materials development.