Implementation of a Three-Dimensional User-Defined Element and Corresponding Artificial Boundary for Dynamic Analysis of Saturated Porous Media in ABAQUS

The dynamic response analysis of saturated porous media is frequently required in engineering practice, which necessitates handy and accurate analysis tools. In view of this demand, the present paper provides a simple user-defined element (UEL) to incorporate the u-w formulation of Biot’s theory for wave propagation in saturated porous media into the general finite element program ABAQUS. As an essential supplement to the UEL, an artificial boundary condition named the multi-transmitting formula (MTF) is embedded into ABAQUS to simulate the semi-infinite far field. The eight-node linear interpolation functions are applied to the 3D fields of the solid skeleton (u) and relative pore-fluid (w) displacements, respectively. The time marching of the resulting finite element equations is achieved by the implicit Hilber–Hughes–Taylor scheme. The details of the implementation and utilization of the UEL and MTF are presented in a detailed tutorial fashion. The developed UEL and MTF are then validated by simulations of six saturated soil dynamic problems, which span a wide range of analysis scenarios. It is demonstrated that the coupled UEL and MTF are effective tools for researchers and engineers to analyze many problems pertaining to the dynamics of saturated porous media.