Simulation of multiple delaminations in composite laminates under mixed-mode deformations

A delamination analysis is developed in order to predict the defect evolution when a fiber composite laminate, with outer layers of equal or different thickness, is subjected to a compression load and multiple delaminations. In particular, the presence of two delaminated zones coaxially positioned on the two opposite sides of the laminate is analysed. In order to accurately predict the growth of delamination, when mode I and II are interacting, some fracture criteria have been proposed. Some results will be given to show the influence on the delamination buckling and on the growth phenomenon of the main geometrical and mechanical characteristics of the structure in order to show the pronounced role of the fracture modes on stable or unstable delamination growth.