Comparative Composite Fatigue Damage Models for Life Prediction of Laminated Composite Structures

Abstract

Two approaches have been compared in this paper for the failure prediction of composite laminate. The first approach is based on a progressive damage model, with the application of LaRC04 as the damage initiation criterion and softening curves to describe damage evolution. Failure strain is calculated elementwise based on a mesh characteristic length in order to ensure its energy dissipation independence of the mesh size. The fatigue damage is evaluated based on stress states and S-N curves, which will be added to the damage calculated from the static balance analysis. The second approach is a hybrid continuum damage and discrete crack representation of the composite matrix failure. While the fatigue damage is computed the same way as in the first approach,, a phantom pair element technique is applied to explicitly characterize the matrix cracking induced displacement discontinuities but the fiber failure is still simulated via a continuum damage approach. Also, the delamination in the second approach is modeled through the element stiffness degradation.