Heat-affected zone in welded cold-formed rectangular hollow section joints

High-strength steel (HSS) has higher strength but lower ductility than mild steel. The cross-section of the structural members may be reduced using HSS instead of mild steel, provided the buckling of elements does not govern the failure. The reduced member size benefits the environment and economy by means of less energy consumption, less carbon...

Experimental investigation on the tensile behaviour of welded RHS high strength steel X-joints

The newest version of prEN 1993-1-8 (2022) prescribes a material factor (Cf) to reduce the design resistance of welded joints made of high strength steel (HSS) mostly due to the lack of available experiments, given the less ductility of HSS compared to mild steel. Additionally, it is stated that the material design yield strength should not...

A macro prediction model for butt-welded (U)HSS connections with softened HAZ

This paper reports an investigation on the tensile resistance of fully-penetrated butt-welded connections of (ultra-)high-strength steels considering the strength softening of the heat-affected zone (HAZ) and the strengthening due to the transverse constraint. Firstly, a parametric study is carried out to analyse the tensile behaviour of...

Equivalent material properties of the heat-affected zone in welded cold-formed rectangular hollow section connections

A welded connection consists of three main material zones, the base material (BM), the heat-affect zone (HAZ), and the weld metal (WM). The strength of HAZ depends on the BM grade and manufacturing process, electrode grade, and welding parameters. Under certain conditions, HAZ has the lowest material strength, especially for high-strength...

A method for determining the constitutive model of the heat-affected zone using digital image correlation

The heat-affected zone (HAZ) is an unmelted region of a welded joint that has changed in material properties because of high temperatures during the welding process. HAZ has a lower strength than the base (parent) material (BM) and the weld metal (WM). The lower material strength is more significant if BM is made of high strength steel and...

Fracture simulation of welded RHS X-joints using GTN damage model

A welded rectangular hollow section (RHS) X-joint exposed to tension loading has three typical fracture-related failure modes: Punching shear failure (PSF), Brace failure (BF), and Chord side wall failure (CSWF). Prediction of these failure modes by finite element (FE) simulations requires modelling of the material damage. An appropriate...

Ductile fracture simulation of cold-formed high strength steel using GTN damage model

The use of high strength steel (HSS) cold-formed hollow section is of significant interest in the construction sector due to competitive costs. The accurate simulation of ductile fracture failure at the micro and macro scale is critical for improving the validity of predicting structural behaviour of HSS cold-formed hollow sections and welded...