Experimental and numerical analysis of mixed mode bending of adhesive-bonded and hybrid honeycomb core sandwich structures

Abstract

This study investigates the potential of a hybrid joining method, called friction stir spot welding with disc and adhesive bonding (FSSW_D_AB), for bonding honeycomb core sandwich structures, offering an alternative to traditional adhesive bonding (AB) sandwich structures. The research focuses on the manufacturing of these hybrid joints and evaluating their performance compared to conventional adhesive bonding (AB) methods. Mixed Mode Bending (MMB) tests were performed to assess the mechanical behaviour of the joints under different loading conditions. Additionally, numerical analysis using cohesive zone modeling (CZM) was performed using both a honeycomb core with a cohesive layer and the homogenized core with an equivalent cohesive layer. The study reveals that the hybrid joining method significantly enhances the performance of honeycomb sandwich structures. The good agreement between the numerical predictions and the experimental results for all types of joints showed the usefulness of the proposed numerical model. However, the FEM-based stress and damage analyses of the joints provided crucial results on normal and shear stress distributions and delamination.