Interface delamination generated by indentation in thin film systems — a computational mechanics study

A finite element method is used to study the onset and propagation of delamination of interfaces in thin film systems during indentation by using a micro-wedge indenter. In the formulation, the interface adjoining the thin film and substrate is assumed to be the only site where cracking may occur. Both the thin film and the substrate are taken to be ductile materials with finite deformation. A traction-separation law, with two major parameters: interface strength and interface energy, is introduced to simulate the adhesive and failure behaviors of the interface between the film and the substrate. The effects of the interface adhesive properties and the thickness of the thin film for cases of a hard film on a soft substrate and a soft film on a hard substrate on the onset and growth of interface delamination are investigated.