Lightning damage analysis of composite bolted joint structures based on thermal-electrical-structural simulation

To analyze the impact of connection behavior on lightning-induced ablation damage in composite bolted joints, this paper analyzes contact properties based on thermoelectric characteristics and develops a lightning ablation damage model for composite interference joint structures. A preliminary analysis of the electrothermal conduction process in the interference-fit composite joints clarifies the influence of connection behavior on lightning damage. The results indicate that a skin effect occurs near the fastener-to-CFRP interface, and both Joule heating and conductive heat significantly affect the temperature distribution in the composite bolted joint structure. A lightning current impact test was also conducted for validation and comparison. Quantitative comparisons show that the predicted in-plane damage aligns well with the experimental results, with an error of 7.37%, while the difference in thickness direction damage is more significant, with an error of 40.02%. Furthermore, the analysis of ablation damage characteristics reveals that the most severe damage occurs in the lower-middle region of the CFRP thickness due to the combined effects of interference damage and bolt preload, while damage in other areas is suppressed.