Study of impact dynamics of porous brittle materials based on a three-dimensional lattice point-spring model

Due to manufacturing, processing, etc., pores are flaws in a variety of brittle materials that can affect the material's impact dynamics properties. Studying the influence of pores and other defects on impact mesoscopic deformation characteristics can further utilize the beneficial functions of pores for engineering applications. Through the use of a 3D lattice point spring model with rotational degrees of freedom (3D-LSMR) that can precisely computationally simulate the fracture evolution mechanism of brittle materials, this paper reveals the mesoscopic deformation properties of spherical pores in brittle materials under impact loading. Under impact loading, pore collapse and shear cracking due to spherical pores can generate stress relaxation. The stress relaxation can evolve the shock-wave into a dual-wave structure of elastic wave (EW) and deformation wave (DW) in samples containing many spherical pores. The calculation results show that the porosity in the samples is an important factor influencing the Hugoniot elastic limit (HEL) of brittle materials. The impact velocity, porosity and material parameter variation factors is the key in influencing the propagation velocity of DWs. The results of the impact mesoscopic deformation characteristics obtained from the study are useful for the topology optimization of porous and brittle materials.