Heat transfer and thermal debonding analysis of honeycomb sandwich panels under laser irradiation

Aerospace structures are increasingly exposed to laser irradiation, and understanding their thermomechanical response is essential for maintaining structural integrity. For honeycomb sandwich panels subjected to moderate-power laser irradiation, rapid temperature variations within the structure generate gradient thermal stresses that may lead to face-core debonding. In this study, a coupled thermomechanical failure analysis was performed to investigate the debonding mechanisms of honeycomb panels under laser irradiation. The effect of the enclosed air on internal heat transfer and thermomechanical behavior was incorporated into the model. The cohesive zone model parameters were determined from pull-off tests to enable the prediction of thermal debonding. Laser irradiation experiments were conducted to validate the numerical heat transfer results. The results indicate that, under identical laser spot sizes and peak laser intensities, flat-top laser irradiation produces significantly larger debonded areas and more pronounced out-of-plane deformation than Gaussian laser irradiation. The observed face-core debonding under moderate-power laser exposure results from the combined effects of adhesive layer failure and air expansion within the cells. These findings provide insight into the debonding mechanisms of honeycomb structures and offer guidance for improving their resistance to laser-induced damage.