Ultimate bearing capacity of marine CFRP deck-bulkhead joints under quasi-static compression: Damage evolution analysis and test verification

In order to explore the ultimate bearing capacity and failure mechanism of deck-bulkhead joints made of carbon fiber reinforced polymer (CFRP) for large ships, full-scale quasi-static compression tests and numerical prediction were carried out. The test results show that the failure of carbon fiber hull joints shows obvious progressive damage characteristics. The damage starts and spreads in the reinforced area, which eventually leads to the main failure modes characterized by fiber failure and adhesive interface debonding. To accurately capture the complex stress redistribution and post-damage energy dissipation within this large-scale joint, a progressive damage analysis strategy incorporating fracture energy and residual stress was employed. The comparative study reveals that the ultimate bearing capacity of the full-scale CFRP joint is influenced by post-damage energy absorption and compressive residual strength. While traditional instantaneous degradation methods artificially truncate the damage propagation path due to unphysical "sudden loss of stiffness", the refined numerical analysis clearly clarifies how localized initial damage physically redistributes and evolves into macroscopic structural collapse. The findings provide a valuable reference and an effective analytical approach for the ultimate strength evaluation of large-scale marine composite joints.