Material characterization of FGM plates using elastic waves and an inverse procedure

Abstract

A computational inverse procedure is presented for characterization of the material properties of functionally graded materials (FGMs) using the surface displacement response of the plate. A modified hybrid numerical method is first developed combining some existing techniques to compute the wave field in an FGM plate for given material properties and their variation in the thickness direction. The modified HNM allows a linear variation of material properties in the element in the thickness direction. This is to reduce the number of elements needed to model the material variation of FGM. The modified HNM is proven more efficient than the original HNM. The high efficiency paves the way for inverse procedure. The reconstruction of the material properties of FGM plates is performed using an inverse procedure of nonlinear least squares method. Numerical examples are presented to demonstrate the present procedure for material characterization of FGM plates. The present procedure can recover accurately the material properties of an FGM with an initial guess of up to 40% off from their true values.