Design method for local model of structural stability of ship stiffened plates under axial compression

. Objective The aim is to study the stability of the overall stiffened plate structure of a ship under axial compressive loads and to propose a local model design method for accurately assessing axial compressive stability. Methods Taking a ship plate frame structure as the research object, a numerical prediction model for the stability of reinforced plates was established based on the ABAQUS finite element software. A comparative analysis was conducted on the ultimate strength and buckling behavior of the overall plate frame and the local plate frame under symmetrical boundary conditions. By systematically varying the longitudinal and transverse dimensions of the local stiffened plate model and its boundary conditions (simply supported, fixed supported), the study investigated the influence of these parameters on structural stability. This led to the development of a local stability model for stiffened plate structures that can characterise the stability of the overall plate frame structure. Results The calculation results indicate that the local plate frame can effectively reflect the third-order buckling mode of the overall plate frame, and the rationality of the symmetrical boundary is good; under fixed boundaries, the single-span, double-span, and triple-span longitudinal reinforced plate models can all effectively reflect the third-order buckling mode of the ideal reference local plate frame. Compared with the reference plate frame, the maximum error in ultimate strength is -0.58%; Compared to single longitudinal rib and four longitudinal rib transverse range models, transverse double longitudinal rib range reinforced plates can better characterise the ideal benchmark local plate frame buckling mode. The error in ultimate strength compared to the benchmark plate frame is -1.60%. Conclusions Adopting the longitudinal single-span, transverse double longitudinal bone locally reinforced plate model and realizing the approximate fixed boundary conditions at the end of the model through the end sealing plate can accurately characterize the ultimate strength and instability modes of the benchmark plate frame while effectively reducing the scale of the experimental model and numerical computation resources.