Compression behaviour of stainless-steel stub square tubular columns at cold-region low temperatures

Abstract

This paper studied the axial compression behaviour of stainless-steel stub square tubular columns (SSSSTCs) at low temperatures (T). Firstly, mechanical properties of stainless steel (SS) S30408 at −80–20 °C were experimentally studied. Test results revealed that decreasing low temperature significantly improved the strength of SS especially the ultimate strength, but reduced its ductility. Twenty SSSSTCs with varying wall thickness were tested at different T of −80–20 °C. Test results showed that inward and outward local buckling took place for SSSSTCs under low temperature-compression. The decreasing T value had significantly positive influence on strength and stiffness of SSSSTCs, but reduced the nonlinear branch of P-Δ curves and ductility of SSSSTCs. The increasing wall thickness significantly improves both strength and ductility of SSSSTCs at different low temperatures due to the reduced width-to-thickness ratio. This paper also developed finite element model (FEM) on simulating compression behaviour of SSSSTCs at different low temperatures that considered geometric imperfections and material nonlinearities. Different code prediction equations were also adopted for predictions of the ultimate low-temperature compression resistances of SSSSTCs. Their accuracies were checked by reported test results.