A coupled FEM-SBFEM approach for soil-structure-interaction analysis using non-matching meshes at the near-field far-field interface

Abstract

Nowadays numerical simulation of soil structure interaction (SSI)is applied to different problems, such as the construction of reliable earthquake-resistant structures. To analyze SSI considering unbounded domains, a numerical implementation of a coupled finite element method (FEM)and scaled boundary finite element method (SBFEM)approach is used. The FEM discretizes the structures and its surrounding soil (near-field)while the infinite half-space (far-field)is realized by the SBFEM. Both methods are coupled at the near-/ far-field interface, where nodal information is exchanged. Computation of far-field solution involves more effort than the near-field, therefore it is convenient to use a coarser mesh for the far-field than for the near-field. In this work, projection methods are used to exchange nodal information at the non-matching boundary meshes. Their implementations are validated first. Then, a coupled FEM-SBFEM scheme which uses these methods is evaluated in two test problems of the SSI framework. Accuracy and stability of the results are analyzed, as well as memory storage and calculation effort savings. Matching mesh results are considered as reference. The solution scheme is finally used to solve a problem which involves a passing train and buildings placed close to its path, attaining good results.