2D Finite-discrete Element Adaptive Coupling Algorithm In Impact Dynamics

Nowadays the mesh-free computing method is an important development direction of impact dynamics simulation algorithms. In this paper, the finite element method combined with the discrete element method and adaptive transform from finite elements to discrete elements was utilized to establishment a two-dimensional adaptive finite element- discrete element coupling algorithm. And designed numerical examples was validated, through SCB sample crack propagation phenomena under shock loading and numerical simulation of warhead penetrating concrete slab, the application of adaptive finite element- discrete element algorithm has been explored.This study mainly include:1) Conducted an investigation of the basic characteristics and calculation processes of the two algorithms FEM and DEM. Studied the different interaction components for DEM model. Compared their own unique strengths and weaknesses and discussed the possibility of combining the two algorithms.2) According to the theoretical principles and calculation processes of the two algorithms, we propose a method using composite element at transition boundary between the computational domain of FEM and DEM for two-dimensional uniform continuous material, designed criterion and transformation rules for adaptive transform from finite elements into discrete elements, and finally established a two-dimensional adaptive finite element- discrete element coupling algorithm.3) Through designed numerical examples, we can see the calculation results of continuous material by FEM and DEM are consistent enough, proving that the method proposed in this paper can effectively combine the two computational domain in different method.4) Prepared calculation program based on two-dimensional finite element- discrete element adaptive coupling algorithm, Through numerical simulations of SHPB experiment on rock SCB sample and steel warhead penetrating concrete slab, initial embodied the value in conversion of continuous to non-continuous and explored the application of the algorithm.This paper is trying to combine the FEM and DEM, the proposed model is relatively simple in handling material constitutive model, so the simulation results of the program is still largely qualitative. Accuracy of the results can only explain the general situation and certain characteristics of materials deformation and fracture during impact process. The next step is mainly thinning algorithm computing model, and expand the scope of application of the algorithm.