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.
Bibliographical noteFunding Information:
This work was supported in part by the National Science Foundation (NSF) under Awards DMR-1607670 and CMMI-1361868. The authors also acknowledge the Minnesota Supercomputing Institute (MSI) at the University of Minnesota for providing resources that contributed to the results reported in this paper. The authors thank Christopher Macosko and his group for helpful discussion and valuable comments.
- Cohesive elements
- Finite element method
- Fracture mechanics
- Mesh dependence