Structural design of cold-formed stainless steel tubular X- and T-joints at elevated temperatures

This paper presents a numerical parametric study on ultimate strength of cold-formed stainless steel tubular X- and T-joints at elevated temperatures. Extensive numerical simulations were carried out on SHS, RHS and CHS tubular X- and T-joints subjected to brace axial compression at different elevated temperatures ranging from 22 to 760 °C. A wide range of geometric parameters and chord preload ratios was considered. The material properties of duplex, high strength austenitic and normal strength stainless steel (AISI 304) were carefully incorporated in the finite element models. The joint strength reduction was compared with the reduction factors of yield stress and elastic modulus of stainless steel materials at elevated temperatures. A unified equation for predicting ultimate strength of X- and T-joints at elevated temperatures was proposed by introducing a temperature factor. The statistical analysis shows that the proposed strength equation is reliable and accurate.