Multiscale algorithm of time and space by coupling discrete element method and finite element method based on element/mesh momentum transfer

A multiscale numerical model of time and space by coupling DEM (discrete element method) and FEM (finite element method) was established. The multiscale numerical model accomplished multiscale time and multiscale space calculations at the same time. Based on the element/mesh momentum transfer,the transition algorithm of mechanical and dynamic parametric variables was deduced. The transition algorithm achieved reasonable information exchange in the coupling transition zone between DEM and FEM,which theoretically solved the smooth transition problem of the physical and the mechanical characteristics between DEM zone and FEM zone in the multiscale computation of time and space. Through an example of elastic stress-wave propagation through a slender rod,the high accuracy and computation efficiency of the multiscale numerical method of time and space were validated.