Investigation of debonding propagation in aluminum/composite joints under fatigue loading

In this paper, Fracture Mechanics is used to predict debonding propagation in adhesive joint between aluminum and composite plates. Three types of loadings (λ = 0, λ = 0.5, and λ = 1 when λ is the ratio of lateral to in-plane loading) and two types of glass–epoxy composite sequences: [0/90]_2s and [0/45/?45/90]_s are considered for the composite plate and their results are compared. It was seen that generally the cases with stacking sequence of [0/45/?45/90]_s have much shorter lives than cases with [0/90]_2s. It was also seen that in cases with λ = 0, the ends of the debonding front propagates forward more than its middle, while in cases with λ = 0.5 or λ = 1 it is vice versa. Moreover, regardless of value of λ, the difference between the debonding propagations of the ends and the middle of the debonding front is very close in cases λ = 0.5 and λ = 1. Another main conclusion was that the non-dimensionalized debonding front profile is almost independent of sequence type or the applied load value.