Experimental, numerical, and ARX model-based prediction of axial buckling capacity in stainless steel cylindrical...

This study investigates the structural behavior of thin-walled cylindrical shells fabricated from stainless-steel pipe under uniform axial compressive loading. Pursuant to this goal, a combined experimental and FE parametric study was performed to develop more generalized design insights for long stainless-steel shell structures. Seventeen specimens with different diameters, thicknesses, and lengths were tested to characterize load-displacement behavior and failure modes. Digital image correlation (DIC) was employed to assess the initial geometric imperfections of the shells, which were then introduced to the numerical models. A nonlinear finite element analysis (FEA) was conducted employing ANSYS software to validate these models against the experimental results. The FE model closely matched the experimental results when considering the peak axial loads of the six tested pipes, with FEA/Test ratios ranging from 0.998 to 1.013 (a difference of approximately - 0.20% to + 1.3%) and an average absolute percentage error of about 0.61%. Based on the validated models, a parametric study using finite element analysis was conducted to evaluate the effects of the radius-to-thickness and height-to-diameter ratios on buckling capacity. Finally, an autoregressive with exogenous inputs (ARX) model was developed as a design-oriented predictor to support the preliminary estimation of nonlinear buckling capacity within the experimentally validated parameter space under uniform axial compression. The proposed capacity model accounts for imperfection amplitude effects and facilitates the evaluation of long stainless-steel shell structures during the design phase.