Optimal penalty stiffness values of concurrent 2D elastic interface elements leading to accurate stress tractions

Zero-thickness interface elements are used to model contact surfaces or potential cracks. In these cases, their elastic stiffness is often set extremely high to reproduce a rigid behavior. This paper shows that the values of the stress tractions at the nodes of these elements can be affected by an error. A new procedure is proposed here, consisting of adding some nondimensional coefficients (purely geometry-dependent) to the values of the interface stiffness parameters. Thus doing, the accurate tractions at the interface nodes are recovered.