Numerical analysis of face sheet/core debonding failure in the plastic forming of aluminum foam sandwich panel

In the present work, face sheet/core debonding failure in the plastic forming of aluminum foam sandwich panel (AFSP) was numerically investigated. The mechanism of debonding failure during the forming process was analyzed first, and then, the bilinear cohesive zone model (CZM) was introduced to simulate the damage and the failure of adhesive layer, and the detailed parameters of CZM were characterized on the basis of the experiments and simulations of flatwise tensile and lap shear of AFSP. Extensive simulations on the plastic forming of spherical and saddle-shaped AFSPs were performed with a macroscopic equivalent AFSP model to gain further insight into the debonding behavior, and multi-point forming experiments were carried out and the deformed parts were scanned using X-ray to verify the face sheet/core debonding predictions using CZM. Furthermore, the effect of cohesive properties on face sheet/core debonding failure was researched, and the results reveal that debonding failure can be avoided by decreasing the initial stiffness of adhesive and increasing the maximum traction and the critical fracture energy of adhesive.