关于采用粗粒化提高颗粒材料多尺度模拟守恒特性的研究

Particle and continuum methods are usually coupled to handle particle-structure contact problems and transitional material behavior between discontinuous and continuous.In this work, we reformulate the surface and volume coupling methods based on a micro-macro transition technique called coarse-graining(CG).For surface coupling, coarse graining allows distributing the coupling forces beyond the elements that the particles are locally coupled with, e.g., from contact points to the neighboring integration points.For volume coupling, coarse-graining enriches the homogenization operation with a non-local contribution from the particles.The generalized coupling terms contain one user-defined parameter, namely, the CG width, setting a length scale for the coarse-grained fields.The advantages of CG in surface and volume coupling are demonstrated via two numerical examples: an elastic cube falling on a granular bed and wave propagation between discrete and continuum media.In this paper, we focus on how the conservation properties of the coupled system are influenced by the CG width.Together with other numerical parameters relevant to the coupling, we show that the CG-enriched formulations lead to better numerical stability and less computational cost for a given energy dissipation ratio.