Prediction of the failure metal/composite bonded joints

Bonded joints became very popular in aircraft, automotive and marine applications. Loading is transferred by adhesion and cohesion forces. These forces are very hard to determine due to a small dimension of bonded joints. Composite/metal double lap joint is investigated. A global model of the double lap joint is presented. A laminated composite structure is manufactured by stacking multiple layers of prepreg. The composite and metal are jointed by an adhesive. Ten prepreg layers and interlaminar interfaces are modelled in the composite substrate. Two thin three-dimensional solids are used in modelling an adhesive bonding composite and metal substrates. Adhesive/substrate and interlaminar interfaces are modelled as two sets of nodes. Interaction stresses (adhesion stress) are determined for each stage of loading. Normal stress in the function of the loading percentage is allowed to show. The Gurson criterion that includes hydrostatic stress sensitivity is used to describe ductile fracture as relation to the nucleation voids in the adhesive. Numerical method is proposed to three-dimensional model interlaminar interface for prediction of delamination initiation as for the static loading. Proposed approach allows to simulate the failure of the joint and composite substrate.