A Unified Phase-Field Approach for Failure Prediction in Modulus Graded Adhesively Bonded Single-Lap Joints

Abstract

This study investigates the effects of overlap length and material variation on the failure behavior of single-lap joints using phase-field analysis (PFA) which is highly robust and suitable for modeling interface problems and multiple crack patterns. In this regard, three different phase field constitutive models are employed within the framework of ABAQUS. The solution to the coupled system equations in the PFA is achieved by using a staggered scheme. The failure analysis of the PFA is addressed with the single-lap joint with a homogeneous adhesive against experimental and cohesive zone model (CZM) solutions. Later, a comprehensive PFA is conducted for the investigation of the influence of the overlap length, material variations in the adhesive layer, and constitutive models on the damage behavior of the adhesively bonded joints with/without modulus-graded adhesives. It is observed that the fracture load levels are highly dependent on the material properties of the adhesive layer and overlap length. The grading concept of the adhesive layer can be considered a good way of preventing possible delamination in the single-lap joint. Moreover, the strength of the single-lap joint may be enhanced by adjusting the overlap length. The PFA provides a promising prediction in dealing with damage onset and evolution in bimaterial and adhesively bonded joints.