A technical review on ultimate strength prediction of stiffened panels in axial compression

In this study, a comprehensive technical review on existing empirical formulations that predict the ultimate limit state (ULS) of a stiffened panel under longitudinal compression was conducted. Recently, Kim et al. (2017) proposed a curve-fitting-based empirical formulation to predict the ultimate compressive strength of a stiffened panel. They found that the ULS behaviour of the stiffened panel fluctuated in the range of 0 < column slenderness ratio (lambda) < 0.5. In this study, a detailed investigation on the lower range value of lambda was conducted using ANSYS Nonlinear Finite Element Method (NLFEM)-based numerical simulation. A total of 10,500 cases were modelled using ANSYS numerical simulation by considering relevant size changes in plate thickness, web thickness, flange thickness, height of web, and breadth of flange. In the case of initial imperfection, only the average level of initial deflection to the plate and initial distortion to stiffener elements were considered, while the residual stress due to welding was not considered. A detailed procedure including the selection of reliable scenarios, Finite Element (FE) modelling, FE analysis, and sensitivity analysis results, was also documented. The obtained outcome will be useful for understanding the ultimate compressive strength behaviour of a stiffened panel. Moreover, the applicability of existing empirical formulations can also be assessed from the statistical analysis results.