Co-Simulation of Fatigue Crack Growth and Delamination Evolution in Cracked Aluminum Plates Repaired with a Composite Patch

Abstract

This study is focused on the development and demonstration of a hybrid structure evaluation and fatigue damage assessment (HYSEFDA) toolkit for fatigue life prediction of cracked aluminum plates repaired with a composite patch. The developed discrete crack network description for a composite system is extended to a hybrid system that consists of a cracked aluminum plate and a bonded composite patch. A phantom paired solid shell element is used for the kinematic description of an arbitrary curvilinear crack in a metallic layer without remeshing. The effect of a thin adhesive layer is characterized as an equivalent cohesive layer described by nodal springs. The virtual crack closure technique (VCCT) approach along with a geometrical mapping algorithm is developed to track a moving delamination front in a mesh-independent manner and to extract the strain energy release rate along the delamination front. The stress intensity factor at the metallic crack tip is calculated using an averaged total energy dissipation approach. The accuracy of prediction of the crack growth driving force is explored using specimens without crack growth while the bridging effect of the composite patch on the reduction of the metal crack opening is demonstrated via a co-simulation of the metallic fatigue crack growth and its associated delamination evolution.