An adaptively coupled DEM–FEM algorithm for geometrical large deformation analysis of member structures

An adaptively coupled discrete element method (DEM)–finite element method (FEM) algorithm is proposed to utilize the respective DEM and FEM advantages. The key problems of the algorithm, such as meeting consistency requirements, determining the adaptive criterion, transferring information between the DEM and FEM and dynamic coupled interface processing, are examined in detail. The adaptively coupled algorithm scheme is formulated. The proposed algorithm is subsequently verified by examples. In the algorithm, the identification of large deformation regions is an automatic process, and the DEM and FEM calculation domains can be changed interactively in every load step in real time according to the structural response. When the response of an arbitrary element in the FEM domain exceeds the predetermined adaptive criterion, the element will be moved to the DEM domain and analysed using the DEM. Similarly, when the response of an arbitrary element in the DEM domain is smaller than the predetermined adaptive criterion, the element will be moved to the FEM domain and analysed using the FEM. The transition of elements between the two domains achieves the objective of using the DEM for large deformation regions and the FEM for small deformation regions.