Prediction of residual stresses in high-strength S690 cold-formed square hollow sections using integrated numerical simulations

• Published in: Engineering structures 2022-02, Vol.253, p.113682, Article 113682
• Main Authors: Xiao, Meng, Hu, Yi-Fei, Jin, Hao, Chung, Kwok-Fai, Nethercot, David A.
• Format: Article
• Language: English
• Subjects: Cold; Cold bending; Cold punching; Cold welding; Cold working; Cold-formed square hollow section; Computer simulation; Experimental investigation; Fabrication; Finite element method; Flame cutting; Heat transfer; High strength steel; Hollow sections; Initial stresses; Mathematical models; Numerical simulation; Plane strain; Residual stress; Springback; Steel structures; Strain analysis; Structural members; Surface temperature; Thermomechanical analysis; Three dimensional analysis; Three dimensional models; Two dimensional analysis; Two dimensional models; Welding
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2021.113682

[Display omitted] •Effects of fabrication on S690 cold-formed square hollow sections were studied.•Transverse bending of CFSHS was modelled numerically by plane-strain analyses.•Longitudinal welding of CFSHS was simulated by coupled thermomechanical analyses.•Measured residual stresses were employed to calibrate these models.•Simplified residual stress patterns for S690 CFSHS were proposed. In general, residual stresses are induced in structural members during various fabrication processes, such as welding, bending, press-braking, folding, flame cutting and punching. The presence of those residual stresses in cold-formed square hollow sections (CFSHS) primarily caused by i) transverse bending (or cold-forming), and ii) longitudinal welding, is widely considered to have modified both initial stress and strain conditions of these steel members significantly. Hence, these residual stresses are widely considered to have significant adverse effects onto the structural performance of these CFSHS under various actions. In order to examine and quantify both magnitudes and distributions of these residual stresses in S690 CFSHS, an investigation is undertaken to measure residual stresses due to transverse bending and longitudinal welding. Moreover, an approach of integrated numerical simulations is adopted in which a total of three co-ordinated finite element models are established together with various element types and block data transfers to generate compatible meshes for the following three analyses: i) two-dimensional plane-strain bending analyses with large plastic deformations and springback, ii) three-dimensional heat transfer analyses for transient temperature distributions under a heat source, and iii) three-dimensional thermomechanical analyses for welding-induced residual stresses. The predicted results of these three analyses have been carefully calibrated against various experimental data, such as surface temperatures during welding, and residual stresses and strains after welding. Good comparisons between the measured and the predicted data of these S690 CFSHS are demonstrated. The complete residual stress distributions within typical S690 CFSHS due to transverse bending and longitudinal welding are illustrated in three-dimensional plots while simplified residual stress patterns of these sections with specific values and parameters are also provided for subsequent advanced structural analyses and design. The proposed modelling technique for transverse