Reflection and scattering analysis of sh-wave using a combined method of bem and ray theory

摘要

An elastic wave scattering in an infinite plate is a simple but important problem to understand behaviors of ultrasound used in a non-destructive testing. In implementing UT(ultrasonic testing) simulation numerically, it is desired to find a scattered field at an observation point taking into account an interaction between a defect and its adjacent boundary. To achieve this end by the conventional BEM(Boundary Element Method), which uses the fundamental solution for an unbounded medium, discretization of the free surfaces in addition to the boundary of a defect is required. When the whole UT system including a transmitter and a receiver must be considered in the simulation, the discretized area of the free surface becomes very large. Therefore, the conventional BEM analysis with the model like this takes an unacceptably large computational time when a plate thickness and/or a distance between the transmission and the reception points of ultrasound are large as compared to the incident wave length. From this reason, a more computationally efficient numerical method has to be developed for UT simulation with a thick plate model.