Rescaling cohesive element properties for mesh independent fracture simulations

In finite element simulations of fracture, cohesive elements introduce artificial compliance into the model leading to changes in properties such as the effective stiffness, effective speed of sound, and crack propagation speed. In this paper, the relation between effective material properties and cohesive element properties is determined analytically. Based on this, a simple method for rescaling the cohesive element thickness is proposed to reduce the effect of artificial compliance and to obtain mesh independent results. The effectiveness of this approach is demonstrated with four example problems: uniaxial stretching, beam bending, bar impact, and Kalthoff plate impact.