FINITE ELEMENT ANALYSIS OF COLD-FORMED STAINLESS STEEL TUBULAR T-JOINTS AT ELEVATED TEMPERATURES

This paper describes the numerical investigation of cold-formed stainless steel tubular T-joints at elevated temperatures. The tubular T-joints were welded from cold-formed square and rectangular hollow sections as brace and chord members. The material properties of high strength stainless steel (duplex and high strength austenitic) and normal strength stainless steel (AISI 304) at elevated temperatures were carefully incorporated in the finite element model. An extensive numerical study of 180 specimens consists of 20 T-joints at different temperatures ranged from 22 to 870 degrees C was conducted. The numerical results were compared with the design strengths calculated from the current design rules for stainless steel tubular T-joints at normal room temperature (ambient temperature) by using the material properties of stainless steel tubes at elevated temperatures. In the calculation of the joint strengths, the reduced material property of 0.2% proof stress was used due to the deterioration of material at elevated temperatures. Furthermore, design rules for cold-formed stainless steel tubular T-joints are proposed by introducing a temperature factor (xi(T)). A reliability analysis was performed to assess the current and proposed design equations.