Objectives To investigate the effects of dents, initial welding deformation and residual stress on the ultimate strength of hull plates under cyclic loading.

Methods The ABAQUS software was utilized in conjunction with its secondary development capabilities to programmatically apply dents to hull plates. The modeling and simulation scenarios comprehensively integrated multiple factors, including welding residual stresses, material properties, and other parameters, to construct a realistic representation of practical conditions. Nonlinear finite element analysis was employed to investigate the influence of varying dent dimensions on the ultimate strength of hull plates with initial imperfections under elastic shakedown conditions.

Results The results indicate that welding residual stress have a significant impact. An increase in dent depth after the state of elastic shakedown reduces residual stress release and intensifies the plastic deformation, leading to a decrease in ultimate strength. The aspect ratio of dents has a complex influence and is related to stress release.

Conclusions This study confirms that the release of welding residual stress and dent parameters under cyclic loading have significant effects on the ultimate strength of hull plates with dents, the results obtained provide a basis for the strength assessment of the hull structure and also offers practical guidance for the design and optimization of the hull structure.