Objectives To assess the destructive vitality of ships and support rapid decision-making on the battlefield, the analysis of the residual load bearing capacity of damaged structures under complex sea state is carried out.

Methods This paper takes the hull plate after explosion damage in the cabin as the research object, and analyses the residual bearing capacity of the thin plate containing dent damage under biaxial compression through the method of model test. By loading with different load ratios, the mechanical characteristics of the dent-damaged thin plate under the combined load are analyzed. Based on the digital image correlation method (DIC method), a three-dimensional full field strain measurement system is established, and the out-of-plane deformation mode of the plate is recorded in detail, which revealing the damage failure mode of the thin plate with dent damage under biaxial compression.

Results The results show that the presence of dent damage significantly reduces the residual load carrying capacity of the thin plate up to 19.96% for any loading ratio. All plates failed due to the large plastic deformation at the angle between the loading edges. As the increase of load at one end of biaxial compression, the ultimate bearing capacity of the other end will significantly decrease.

Conclusions The study is of great significance in guiding the assessment of ship's destructive vitality and safe return to harbor under complex stresses.