Numerical simulation of guided waves using equivalent source model of magnetrictive patch transducers

Abstract

While magnetostrictive patch transducers have become more widely used for damage inspection of waveguides such as plates or pipes, the numerical simulation of guided waves excited by the transducers is very limited.

Recently, one-way coupled time-harmonic finite element analysis based on the linearized magnetostrictive coupling equation has been conducted but transient analysis must be carried out for extracting more information including the reflected waves from cracks. Fully-coupled or one-way coupled multiphysics transient finite element analysis is quite complicated and also requires enormous computational resources.

In order to utilize an advanced structural finite element method or code, we newly propose equivalent distributed force models that can describe the actuation mechanism of the magnetostrictive patch transducer without explicitly solving coupled multiphysics equations. Once equivalent force models are established, transient wave simulations in inspected waveguides can be accomplished efficiently through any structural finite element code.

The essence of this approach is to establish the equivalent actuating force models useful for various types of magnetostrictive patch transducers that are currently available. The validity of the developed models is checked by investigating the wave radiation patterns of the Rayleigh-Lamb and shear-horizontal waves in test waveguides and the simulated results obtained with the proposed models are compared against available experimental results.