A stabilized finite element method for delamination analysis of composites using cohesive elements

TL;DR

This paper introduces a stabilized finite element method inspired by the weighted Nitsche approach, effectively reducing traction oscillations at interfaces in composite delamination analysis, and allowing for more accurate and robust simulations.

Contribution

The paper presents a novel stabilized finite element method that mitigates traction oscillations and removes the need for estimating minimum cohesive stiffness in delamination modeling.

Findings

Stabilized method reduces traction oscillations in simulations.

Method works effectively with large cohesive stiffness values.

Robustness demonstrated across various delamination tests.

Abstract

We demonstrate the ability of a stabilized finite element method, inspired by the weighted Nitsche approach, to alleviate spurious traction oscillations at interlaminar interfaces in multi-ply multi-directional composite laminates. In contrast with the standard (penalty-like) method, the stabilized method allows the use of arbitrarily large values of cohesive stiffness and obviates the need for engineering approaches to estimate minimum cohesive stiffness necessary for accurate delamination analysis. This is achieved by defining a weighted interface traction in the stabilized method, which allows a gradual transition from penalty-like method for soft elastic contact to Nitsche-like method for rigid contact. We conducted several simulation studies involving constant strain patch tests and benchmark delamination tests under mode-I, mode-II and mixed-mode loadings. Our results show clear evidence of traction oscillations with the standard method with structured and perturbed finite element meshes, and that the stabilized method alleviates these oscillations, thus illustrating its robustness.