Objectives In order to accurately assess the ultimate load-bearing capacity of the hull structure under cyclic loading, it is necessary to consider the effect of cyclic properties of the load on the ultimate strength of the hull stiffened plate.

Methods The finite element software ANSYS was used to carry out the numerical simulation of ultimate strength based on elastic shakedown state under in-plane cyclic loading for 200 Tee-bar stiffened plates and flat-bar stiffened plates. The material Bauschinger effect, welding initial deformation and residual stresses of the hull stiffened plate under in-plane cyclic loading were considered in detail. Based on the stiffened plate nonlinear finite element numerical simulation results of the limit state of elastic shakedown. The dimensionless ultimate strength of the stiffened plate was taken as the objective function, and the flexibility coefficients of the plate and the stiffener were taken as the independent variables, and the formulas for predicting the ultimate strength of the hull stiffened plate under in-plane cyclic loading based on the limit state of elastic shakedown were proposed.

Results The accuracy of the formulation is verified by comparing it with the results of nonlinear finite element simulation.

Conclusions The work done in this study has good theoretical and engineering significance for the ultimate strength assessment of hull stiffened plates under cyclic loading.