Residual stresses and strength of hollow stainless steel sections

Austenitic and duplex stainless steel grades are becoming common in the construction industry and their use has grown significantly in last years. The paper presents research into shape and size of residual stresses in cold formed longitudinally welded rectangular/square hollow austenitic steel sections and their influence on strength capacity of the members. Arrangement of the measuring by X-ray diffraction method, used instrumentation and results with respect to the effect of longitudinal welding are given in detail. The resulting true residual stresses are subsequently used in the FEM model to determine their influence on resistance of the member in compression. Further, the model includes non-linear stress-strain diagram and enhanced strength corner properties to obtain relevant credibility of the solution. As well stub column tests being under way are described. Finally, summary of the results and future perspectives for encompassment of the residual stresses into design are presented.