Modelling of Debond and Crack Propagation in Sandwich Structures Using Fracture and Damage Mechanics

Skin-core de-bonding or core crack propagation will often be dominating mechanisms in the collapse modes of sandwich structures. This paper presents two different methods for prediction of crack propagation in a sandwich structure: a fracture mechanics approach, where a new mode-mix method is presented, and a local damage mechanics approach.

The paper presents a real-life application example, where the superstructure in a vessel pulls the skin off the sandwich deck. The calculations show almost unstable crack growth initially followed by a stabilization, and a nearly linear relation between lifting and crack length. A remarkably good agreement is found between the results of the fracture and damage mechanics approaches.