New anisotropic perfectly matched layer boundary condition for elastic waves in solids

The perfectly matched layer (PML) is currently a popular absorbing boundary condition for numerical modeling of electromagnetic, acoustic, and elastic wave problems. Existing PML formulation for elastic waves uses a field splitting scheme, which increases the number of variables in the computation. The new anisotropic elastic wave PML modifies the elasticity or compliance tensors to be anisotropic. It utilizes fewer variables for both isotropic and anisotropic media, so that computing memory and time can be reduced significantly. Its formulations for Cartesian and curvilinear coordinate systems will be discussed. Moreover, this anisotropic PML can be directly used in the finite element method, and easily be implemented in the finite difference time domain method as well. [Work supported by NASA (NAG3‐2147) and by NSF (CTS‐9870015).]