Wave Propagation Analysis Considering Scattering on Grain Boundaries in Solids by Finite Element Methods

Abstract

With the demand of high accuracy of defection and sizing in ultrasonic testing, numerical modeling of wave propagation needs to consider the scattering of waves among the boundaries of crystal grains. In this paper, a method is developed for automatically generating grain boundaries in finite element models. The properties of received signals in intensity and frequency spectrum by simulations are compared with those by experiments. They are in excellent agreement. This model is also applied to the numerical analysis of the wave propagation under longitudinal angle beam testing for solids with various average grain diameters. Numerical results show that a diffracted longitudinal wave can be easily measured in the case where the average grain diameter is smaller than 80 μm but it is diffcult to identify the diffracted longitudinal wave when the average grain diameter is larger than 150 μm because the diffracted waves are probably masked by the scattering waves on the grain boundaries. Moreover, numerical results also show that the crystal grain model developed in this paper provides an effective way to model wave propagation quantitatively.