Effect of geometric imperfection and residual stress on the finite element modelling of stainless steel I-sections subjected to lateral-torsional buckling

All rights reserved. Stainless steel Is a group of steel alloy with versatile crystal structures and material behaviours. Its characteristic nonlinear, rounded stress-strain behaviour without well-defined yield point makes it different from carbon steel. The degree of nonlinearity and roundness vary significantly from one grade of stainless steel to another which also increases the challenge to give a uniform formula for predicting the ultimate capacity of stainless steel sections of all grades. Presence of initial geometric imperfection and residual stress in structural member lead to premature yielding and loss of stiffness eventually reduces the load bearing capacity. For both structural design and finite element simulations, knowledge of their magnitude and distribution is therefore important. Recent years saw keen interest from the researchers on discovering the imperfection and residual stress pattern of stainless steel welded l-sections. Current study utilizes these findings to develop of finite element (FE) models for previously experimented stainless steel I-beams subjected to lateral-torsional buckling. Types of initial geometric imperfections, residual stresses and boundary conditions were varied In the FE models. Capacity of the developed FE models when compared with that of the lateral-torsional buckling experiments, revealed the influence of the variables considered. Understandings from this study will help further to develop finite element models for parametric study on stainless steel I-beams, consequently leading to evaluate the performance of the International design guidelines and propose new formulations.