Simplified ultimate strength estimation method of continuous stiffened panels under biaxial loads and lateral pressure

A simplified method is proposed for estimating the ultimate strength of continuous stiffened panels subjected to combined longitudinal and transverse loads, as well as lateral pressure. For the more rational design of ship hull structures, it is essential to develop an estimation method with a solid physical basis. Previous methods have been developed theoretically, explicitly considering factors such as post-buckling and yielding behaviors in addition to initial deflection. However, these approaches often require numerical iterations, such as the Newton-Raphson method, to obtain the load-deflection relationships. In this study, analytical solutions are derived for the elastic post-buckling behaviors of stiffened panels, eliminating the need for numerical iterations; this enables the development of a simple yet practical method for estimating the ultimate strength. By observing and classifying the collapse behavior of stiffened panels through nonlinear finite element analysis (NLFEA), the ultimate strength can be predicted by assessing yielding at predefined locations corresponding to the identified collapse modes. The accuracy of the proposed method is validated through comparisons with NLFEA results.