EXPERIMENTAL AND UNIFIED MODEL INVESTIGATIONS ON RESIDUAL STRESS WITHIN HIGH STRENGTH STEEL WELDED I-SECTIONS

To study the distribution of residual stress within high strength steel welded I-sections for various steel grades, three specimens made of 960MPa high strength steel are measured using the sectioning method. By comparing current experimental results with a large quantity of existing test data, including those of 235MPa, 345MPa, 460MPa and 690MPa steels, the tensile and compressive residual stress are investigated. It is found that the effect of geometry on the tensile residual stress (i.e. the width to thickness ratio and thickness of sectional component plate) is not obvious, whereas the effect is significant on the compressive residual stress. With an increase in the steel strength, the tensile residual stress increases but is always less than the steel strength, whilst the compressive residual stress has hardly any correlation with the steel strength. On the basis of this research, the calculation formulae of both tensile and compressive residual stress of welded I-sections for various steel grades are proposed. The unified model of the residual stress distribution for such sections is established, and it is expected to provide valuable information and fundamental knowledge for further research into high strength steel structures.