Damage sequence of honeycomb sandwich panels under bending loading: Experimental and numerical investigation

This work presents a numerical modelling study on the bending response and failure mechanisms of aramid skin/aluminium honeycomb core sandwich panels under quasi-static bending loads. These composite sandwich panels are widely used in aerospace and automotive industries, in spite of the limitations for their use in complex structures, such as the extensive experimental testing needed at the component and full-size structural levels, which are expensive and time-consuming. The aim of this study was to capture the initiation of different failure mechanisms and their multiple interactions, which are known to strongly influence the observed microscopic behaviour of the material. Furthermore, a series of detailed Finite Element models were built and analysed in an attempt to replicate the complex damage mechanisms observed experimentally. The results show good correlation between numerical models and experimental results, both in terms of the global load-displacement behaviour and the observed damage mechanisms, including skin in-plane shear and compression damage, intralaminar fracture, delamination within the skin and core crushing. No debonding between the core and the skins was evidenced. It is proposed that this modelling approach can become a feasible alternative to component-level experimental testing when designing complex sandwich structures.