Application of PML to Analysis of Nonlinear Soil-Structure-Fluid Problem Using Mixed Element

Mixed element may be conveniently used to express non-linear constitutive equation of fluid and to avoid volumetric locking. X-FEM may be well suited to model discontinuity of displacements between solid and fluid. Appropriate boundary conditions should be set at the boundaries of numerical models not to reflect outgoing waves. In this paper, complex frequency shifted convolution-PML without splitting of variables is developed for mixed element, and the performances of PML are confirmed. The formulation of PML is completely consistent with corresponding FEM or X-FEM. It can be easily extended to any type of element and any nonlinear constitutive equations of the corresponding FEM or X-FEM. The resulting mass and stiffness matrices for PML are symmetric for linear models