Electrical-thermal response of composite honeycomb sandwiched structures under lightning strike

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This study experimentally and numerically investigated the lightning strike (LS) damage in carbon fibre reinforced polymer (CFRP) composite honeycomb sandwich structures (CHSSs), aiming to address the limited understanding and lack of predictive capability for LS damage in such widely used yet structurally complex aerospace materials. Firstly, a series of simulated LS experiments were conducted on CHSSs, and the resulting LS damages were characterised using visual inspection, ultrasonic scanning and micro-computed tomography to identify typical material and structural failure modes. Then, a novel coupled electrical-thermal finite element (FE) model of CHSSs under LS was developed to predict the lightning-induced damage in such sandwich structures for the first time, addressing a knowledge gap in previous numerical studies which primarily focused on conventional CFRP laminates rather than structurally complex CHSSs. It was found that the FE-predicted LS damage area and depth showed good agreement with the experimental results with deviations of less than 16%, demonstrating the effectiveness of the FE model. Finally, the LS damage mechanism of CHSSs was explored and the effect of variations in honeycomb core thickness on the LS damage was examined by the proposed FE model, providing new perspectives on tailoring CHSS designs for enhanced LS resistance.