Ultimate Compressive Strength of Imperfect Unstiffened Plates: Simple Design Equations

Abstract

A simple design equation for predicting the ultimate compressive strength of unstiffened plates with misalignment, initial deflection, and welding residual stresses is developed in this study. A nonlinear finite element method is used to investigate the ultimate strength of the imperfect plate. The method incorporates both geometric and material nonlinearity. Buckling and plasticity behavior of the plate can be expressed using this finite element system. The results from the finite element method and an analytical method using large deflection theory together with rigid-plastic theory are compared. It was found that the analytical method using large deflection and rigid-plastic theory is not always accurate. Reduction factors of the ultimate strength due to welding residual stresses and initial deflection are generated from the results of the nonlinear finite element method. A new equation for ultimate strength of imperfect plates was developed using these reduction factors. The accuracy of the proposed new equation is confirmed by comparing it with the finite element results.