Effects of thickness on the largely-deformed JKR (Johnson–Kendall–Roberts) test of soft elastic layers

The paper aimed to study the effect of large deformation and material nonlinearity on the adhesive contact between a smooth rigid spherical indenter and a Neo-Hookean layer of finite thickness, for the cases of the layer thickness/indenter radius ratio between 1 and 2. Our analysis was based on the large-deformation JKR (LDJKR) theory, which models the adhesive contact of two elastic solids in large-deformation regime by knowing the solution of the corresponding non-adhesive contact problem. In this paper, the non-adhesive contact between a spherical indenter and a Neo-Hookean layer was solved by finite element analysis. Combined these numerical results and the LDJKR theory, approximate analytic expressions of the applied load and displacement of adhesive contact of Neo-Hookean layers were obtained. The effects of layer thickness were also discussed.