• LVI
• low velocity impacts
• delaminations
• compression after impact
• CFRP
• CAI
• post-buckling
• wing stiffened panel

Carbon fibre reinforced plastics, though carrying excellent specific properties, present also new and not yet completely understood damaging processes. Delaminations, above all the damage mechanisms, pose a serious threat to aerospace structures, because of their difficult detectability and the associated strength reduction. Taken into account the prohibitive costs of extensive experimental campaigns, the development of reliable numerical tools, capable of correctly modelling the onset and propagation of delaminations, is the key for lighter and safer structures.

The aim of this work is to expand the knowledge on innovative techniques for the simulation of delaminations. The interlaminar behaviour is simulated using Abaqus cohesive elements endowed with a user written material subroutine (UMAT), that implements the constitutive cohesive zone model. Standard low velocity impact tests on multi-directional laminates are simulated and results in terms of forces and delaminated areas are assessed. Non-linear post-buckling analyses on damaged wing stiffened panels are performed in order to determine the effects of skin-to-stiffener debonding. A simple procedure for injecting artificial delaminations is presented. Ultimately, it is shown that the adopted techniques well predict delaminations caused by impact events onset and their propagation under static compression loads.