Finite element implementation of efficient absorbing layers for time harmonic elastodynamics of unbounded domains

An alternative approach to local transmitting boundaries for wave propagation problems in unbounded media is the application of the Perfectly Matched Layers (PML) around the finite region of interest. The PML model consists of absorbing layers that absorb almost perfectly propagating waves of all non-tangential angels-of-incident and all non-zero frequencies. This paper presents and verifies the concept of FE/PML methodology on the basis of two different formulations for the PML model in the context of time harmonic wave propagation analysis. A finite element numerical scheme is developed in which both PML formulations are successfully implemented as a macro-finite element in a commercial FEM program. Moreover, the parameters that influence the performance of the FE/PML method are extensively discussed and recommendations are given for the proper selection. Classical soil-structure interaction problems of surface or embedded rigid footing on homogeneous or heterogeneous half-plane containing layers and tunnels are investigated and the high accuracy and the easy implementation of FE/PML computational tool is demonstrated.