Mesoscale analysis of deformation and fracture in coated materials

The deformation and fracture of a coated material are simulated. A dynamic boundary-value problem in a plane strain formulation is solved numerically by the finite-difference method. To simulate the mechanical response of the steel substrate use was made of the relaxation constitutive equation based on microscopic dislocation mechanisms. A fracture criterion takes into account crack origination and growth in the elastic-brittle coating. Numerical experiments were conducted for varying strain rate of tension and compression. Macroscopic behavior of the coated material is shown to be controlled by interrelated processes of localized plastic flow in the substrate and cracking of the coating that strongly depends on an external strain rate.