Research on the residual dynamic ultimate strength of cracked stiffened plates under in-plane impact

This study investigates the dynamic ultimate strength and failure behavior of a typical stiffened hull plate subjected to in-plane impact loading. A nonlinear finite element method is employed to systematically investigate the influence of impact duration, crack damage parameters, and structural geometric parameters on the dynamic ultimate load-carrying capacity of the damaged structure. Based on 328 sets of numerical simulations, a regression analysis was conducted to develop an empirical formula for rapid prediction of the dynamic ultimate strength of cracked stiffened plates. The empirical formula is validated through cross-comparison with finite element analysis results obtained from realistic ship structural models. The comparative assessment reveals that the predictions yielded by the empirical formula exhibit strong overall agreement with the FEA results, with a mean absolute error of 2.43% and a maximum absolute error of 9.67%. This study establishes a theoretical foundation and provides a technical reference for the dynamic strength assessment and safety-oriented design of ship structures with damage under in-plane impact loading.