Finite element modeling of the scratch response of a coated time-dependent solid

Scratch tests is one of the most efficient tests to investigate the mechanical resistance of coated and uncoated surfaces. Nevertheless, the complexity of material and interface makes difficult the comprehension of this test. For that purpose, efficient computational modeling is required. In this paper, we present a remeshing procedure specially developed for the computational modeling of scratch tests of coated materials. This procedure allows to perform scratch tests with high ratio penetration depth over layer thickness. Then, it is used to investigate the influence of the scratching velocity on the scratch behavior of a polymer substrate coated with a hard elastic coating. The substrate is considered as an elastic–viscoplastic solids and the coating follows a linear elastic behavior. First macroscopic results such as material deformation, scratch hardness and apparent friction coefficient are presented. Then the stress distribution in the film and at the coating/substrate interface are analyzed regarding the cohesive or interfacial failure of the system. A simple interfacial failure criterion is also proposed.