Modelling of Cyclic Delamination Behavior of Thin Multilayered Structures Using Gradient Elasticity and Damage Accumulation

Abstract

Cyclic delamination experiments with multilayered structures were performed in four point bending mode using a central notch for crack initiation. In a preceding study, the propagation of the delaminating cracks could be interpreted on the basis of the Paris law. In order to obtain more insight into the mechanisms of fatigue and crack propagation, FEM simulations of the experiments were conducted. The material models used in the simulation involve strain gradient elasticity, kinematic hardening plasticity and creep. Following the concept of damage mechanics, the crack propagation rate of delamination was related to the inelastic strain accumulated per loading cycle. Thereby, singularities of stresses and strain at the crack tip were suppressed by the regularizing effect of strain gradient elasticity.