Numerical modelling of lean duplex stainless steel and assessment of existing design methods

Abstract

The longevity and unique mechanical properties of stainless steel are sufficient reasons for adopting it as a main material in the construction industry. However, its high initial cost, which is largely influenced by the level of nickel content (8% - 10% in the common austenitic grade), relatively restricts its application in structures. The development of lean duplex stainless steel, a low nickel grade offering twice the strength of the austenitic grade at nearly half the initial cost, and refining the codified design equations, may increase the usage rate of stainless steel in construction. The aim of this paper is to continue the previous research conducted on lean duplex stainless steel by providing more data on its structural performance using numerical modelling and evaluating existing and proposed design equations which were not available earlier. A detailed description of the modelling using the general-purpose finite element analysis package ABAQUS is presented. Forty-eight lean duplex stainless steel welded I-sections loaded in bending and shear were simulated. The obtained numerical results are reported and used in conjunction with existing experimental and numerical data on stainless steel welded I-sections to assess the Eurocode 3: Part 1.4 codified slenderness limits and shear resistance design equations, the continuous strength method (CSM) for bending and newly proposed shear design equations. Analysis of the results reveals that the current codified design provisions are generally conservative and improved predictions can be achieved using the CSM and the proposed slenderness limits and shear resistance equations.