Numerical Simulation and Damage Mechanism Study of Lightning Resistance in Double‐Double Composite Laminates

ABSTRACT Double‐Double (DD) laminates are emerging as a promising lay‐up design that employs a unique [± Φ , ± Ψ ] nT stacking sequence to replace the traditional use of discrete 0°, ±45°, and 90° plies in QUAD laminates. Despite the growing interest in DD laminates, their lightning strike resistance and post‐lightning mechanical behavior remain insufficiently explored. This paper aims to investigate the damage characteristics of DD laminates subjected to lightning strike loading and their subsequent compression performance. To this end, a high‐fidelity electro‐thermal‐chemical multi‐physics finite element model is employed and sequentially coupled with post‐strike compression simulations to predict the damage evolution and residual load‐bearing capacity of QUAD and DD laminates designed with equivalent in‐plane stiffness under a 75 kA lightning current. Numerical results show that, under identical lightning conditions, DD laminates exhibit more uniform potential and temperature distributions, reduced through‐thickness ablation, and more localized damage zones compared with their QUAD counterparts. For 32‐layer laminates, soft lay‐ups experience a more pronounced degradation in load‐bearing capacity than quasi‐isotropic (QI) lay‐ups under lightning impact. Nevertheless, both QI and soft DD laminates with equivalent stiffness demonstrate superior lightning resistance and damage tolerance relative to QUAD laminates. When the laminate thickness is reduced by 50%, the detrimental effect of lightning strikes on residual performance increases significantly with the ratio of damage depth to laminate thickness (relative damage depth). However, the model predicts that the DD design sustains a higher residual load ratio, with DD_SOFT exhibiting the highest residual load ratio among the thin laminates due to its lowest relative damage depth.