Stability maps for the slightly compressible poker chip detachment problem

The “poker chip problem” was originally investigated experimentally to create hydrostatic tension in rubber-like materials. Different modes of contact failure were already described during these experiments. Since then, this problem has proven to be useful for investigating the detachment mechanisms of dry adhesives. This is primarily achieved with FE simulations, as many important quantities cannot (or too difficult to) be measured in a real experiment setup.

Detachment is investigated with the theoretical toolset of linear fracture mechanics. This article focuses on the so-called edge detachment (when detachment initiates along circumference of the interface) and center detachment (when detachment occurs at the middle of the contact interface). Both cases are investigated for propagation stability with respect to the two main governing parameters of this problem: chip thickness and volumetric compressibility, characterized by the Poisson’s ratio.

The map of the stable regions is presented based on these parameters. A stability island is identified in case of edge detachment. It is shown that the edge detachment case is more sensitive to changes in Poisson’s ratio.