Elasto-plastic fine-scale damage failure analysis of metro structures based on coupled SBFEM-FEM

Abstract

This paper presents a new high-performance, fine-scale damage analysis method using three techniques. Firstly, efficient and detailed mesh discretization is performed via octree, which can easily accomplish cross scale and thus significantly alleviate the burden of fine modelling using octant cubes. Secondly, the introduction of coupled scaled boundary finite element (SBFEs) into FEM can offer more generality, flexibility and conveniences. Thirdly, the parameter matrices (e.g. stiffness, mass, damping) of geometrically similar elements generated by octree are proportionable and can be pre-computed. Therefore, by leveraging the similarity among elements for elasto-plastic problems will significantly improve computational efficiency. In order to demonstrate the effectiveness of the new approach, a fine-scale damage evolution of DaiKai subway was comprehensively modelled using different mesh sizes. Plastic damage and generalized plasticity models for soil and interfaces were used. Results from the case study demonstrated that octree possesses the advantages of high robustness, ability for automation and capacity to work with fewer elements during mesh generation. The coupled SBFEM-FEM and the use of element similarity markedly improved the computation cost (50% computation time was reduced). The presented method bypasses the need for undesired compromise between simulation accuracy and solver efficiency.