Material response and local stability of high-chromium stainless steel welded I-sections

• Main Authors: Sun, Yao, Zhao, Ou
• Other Authors: School of Civil and Environmental Engineering
• Format: Article
• Language: English
• Published: 2021
• Subjects: Engineering::Civil engineering; Continuous Strength Method; Design Codes
• Online Access: https://hdl.handle.net/10356/150786
• Institution: Nanyang Technological University

The present paper describes a thorough testing and finite element modelling programme on the material characteristics and local stability of welded I-sections made of a new high-chromium grade EN 1.4420 stainless steel. Structural testing was conducted on four GMA (gas metal arc) welded I-sections, and involved material testing, residual stress measurements, initial geometric imperfection measurements, eight stub column tests and eight four-point bending tests, with four for each axis of bending. A parallel numerical modelling study was then carried out, in which numerical models were developed and validated against the obtained experimental results and afterwards utilised to perform numerical parametric studies to generate additional data to supplement the test results over a broader spectrum of cross-section geometric dimensions. The experimentally and numerically obtained data were employed to evaluate the suitability of the codified slenderness limits for cross-section classification and local buckling design provisions in both Europe and America to welded I-sections made of the new high-chromium grade EN 1.4420 stainless steel. The results of the comparisons generally indicated that the established cross-section slenderness limits are applicable to the new high-chromium stainless steel welded I-sections, while the codified local buckling design rules, based on an elastic, perfectly plastic material model without taking into account the material strain hardening effect of stainless steel and the effective width method without considering the element interaction effect within the cross-section, yield safe but unduly conservative and scattered cross-section local buckling resistance predictions. The accuracy of a recently proposed continuous strength method to the design of this new type of stainless steel welded I-sections was also evaluated, indicating a substantial improvement over the established design codes, mainly owing to the rational consideration of the favourable effects of material strain hardening and element interaction in the calculation of cross-sectional capacities.