LOW-TEMPERATURE COMPRESSION BEHAVIOUR OF CIRCULAR STUB STAINLESS-STEEL TUBULAR COLUMNS

This paper firstly studies mechanical properties of stainless steel (SS) S30408 at the low temperature (T) range of -80~20℃. Further compression tests are carried out on 20 SS stub tubular columns (SSSTCs) at low temperatures of -80, -60, -30, and 20℃ to investigate their low-temperature compression behaviour. Including the testing low temperatures, the wall thickness of SS tube (t) is the other investigated parameters. Test results show that decreasing the T from 20 to -80℃ improves the yield and ultimate strength of stainless steel by 29% and 80%, respectively, but reduces its ductility by about 25%. Under low-temperature compression, elephant foot local buckling occurs to most of SSSTCs and inelastic inward and outward local buckling occurred to specimens with 6 mm-thick SS tube. Test results also show that the decreasing T value increases the strength and stiffness of SSSTCs, but compromises their ductility; the wall thickness of SSSTCs significantly improves their strength, stiffness, and ductility. This paper also develops 3D finite element model (FEM) to estimate the low-temperature compression behaviour of SSSTCs, which considers nonlinearities of material and geometry, geometric imperfections, and influences of low temperatures. The validations show it predicts reasonably well the low-temperature compression behaviours of SSSTCs.