A Coupled Finite Difference Material Point Method and Its Application in Explosion Simulation

摘要

The material point method (MPM) discretizes the material domain by a set of particles, and has showed advantages over the mesh-based methods for many challenging problems associated with large deformation. However, at the same time, it requires more computational resource and has difficulties to construct high order scheme when simulating the fluid in high explosive (HE) explosion problems. A coupled finite difference material point (CFDMP) method is proposed through a bridge region to combine the advantages of the finite difference method (FDM) and MPM. It solves a 3D HE explosion and its interaction with the surrounding structures by dividing the problem domain into FDM region and MPM region in space. FDM is employed to simulate the region where the detonation products disperse into the surrounding air, while the FSI region is simulated by MPM. A bridging region is employed to exchange the information. In the bridge region, MPM provides the boundary condition for FDM region by mapping the variables from MPM background grid nodes to FDM fictitious points, while FDM provides the boundary condition for MPM region by mapping the variables from FDM cell-centre points to MPM interface grid nodes. The transportation between the two computational regions is implemented by moving particles in the bridge region. Numerical results are in good agreement with those of theoretical solutions, empirical formula and experiments. No obvious interface effect are observed in the bridge region in numerical tests.