Simulation of the stress state in barriers made of anisotropic materials

To study the properties of anisotropic materials, a mathematical model is proposed that accounts for the anisotropy of elastic and plastic properties, as well as the anisotropy of “thermal” and “cold” components of pressure. The model is applied in a threedimensional simulation of the deformation of an HCP-single-crystal barrier under impact loading by an aluminum impactor. The numerical simulation results are obtained using the dynamic finite element method with a difference scheme modified to account for the anisotropy of “cold” and “thermal” pressure components. To simulate the anisotropy of the stress deviator in the region of elastic deformations, generalized Hooke's law is used, while in the region of plastic deformations, the Mises-Hill plasticity function (Hill48) is used with account for the anisotropy of elastic properties and anisotropy of the Gruneisen coefficient. The experimentally and numerically obtained velocity profiles of the back surfaces of single-crystal zinc barriers during the spall fracture are compared with each other. When the impact loading direction coincides with [0001] axis, the elastic precursor is not observed on the velocity profile calculated numerically, which is the same for the one derived experimentally. This effect may be explained only with the use of anisotropic pressur.