Simulation of nonlinear ultrasonic waves in anisotropic materials using convolution quadrature time-domain boundary element method

摘要

In recent years, a new ultrasonic nondestructive testing method that utilizes nonlinear ultrasonic behavior generated in cracks or at a bi-material interface has emerged. However, the mechanism of generating subharmonics and higher harmonics is theoretically still not well understood. In this research, to simulate higher harmonics, dynamic contact problems of a crack face with contact boundary conditions in anisotropic materials are investigated by the Convolution Quadrature Time-Domain Boundary Element Method (CQBEM). Numerical results show that the cracks with contact boundary conditions in anisotropic materials excite higher harmonics as well as those in isotropic ones.