A novel method in solving seepage problems implementation in Abaqus based on the polygonal scaled boundary finite element method

The scaled boundary finite element method (SBFEM) is a semi-analytical computational scheme, which is based on the characteristics of the finite element method (FEM) and combines the advantages of the boundary element method (BEM). This paper integrates the scaled boundary finite element method (SBFEM) and the polygonal mesh technique into a new approach to solving the steady-state and transient seepage problems. The proposed method is implemented in Abaqus using a user-defined element (UEL). The detailed implementations of the procedure, defining the UEL element, updating the RHS and AMATRX, and solving the stiffness/mass matrix by the eigenvalue decomposition are presented. Several benchmark problems from seepage are solved to validate the proposed implementation. Results show that the polygonal element of PS-SBFEM has a higher accuracy rate than the standard FEM element in the same element size. For the transient problems, the results between PS-SBFEM and the FEM are in excellent agreement. Furthermore, the PS-SBFEM with quadtree meshes shows a good effect for solving complex geometric in the seepage problem. Hence, the proposed method is robust accurate for solving the steady-state and transient seepage problems. The developed UEL source code and the associated input files can be downloaded from https://github.com/yangyLab/PS-SBFEM.