Design of Stainless Steel Cross‐Sections by Inelastic Stability Analysis

While carbon steel cross‐sections are traditionally categorized as Class 1, 2, 3 or 4, depending on when local instability occurs relative to the key stages of yielding, for stainless steel the lack of a well‐defined yield point and the presence of continual strain‐hardening render this approach artificial and superfluous. A new design methodology is therefore needed, which accounts for the effects of both strain‐hardening and local buckling.

The proposed method is based on a modified finite strip method, which accounts for the effects of gradual loss of stiffness due to yielding on the stability of thin‐walled members. Extensive verification of the new method against experimental data showed that cross‐sectional capacities are generally well predicted, with average ratios of the measured to the predicted capacity of 1.18 and 1.19 in compression and bending, respectively, and a standard deviation of 0.10 in both cases. This is a significant improvement over the EN 1993‐1‐4 design rules, where the averages over the same dataset were 1.27 and 1.40, respectively, with standard deviations of 0.14 and 0.17. The rotational capacity of stainless steel cross‐sections in bending was also reasonably well predicted, with an average ratio of measured to predicted curvature of 1.79.