Member ductility and design detail of some welded joints
The behaviour of tubular steel members and their connections are studied under ultimate tensile load conditions. Three end connection details are considered. These are practical connections, but one has a deliberately introduced defect of welding fabrication detail. Two types of steel are used: one is a conventional semi-killed mild steel, while the other is a rimmed steel that has been cold formed to produce an enhanced yield stress. The ratio of ultimate stress to yield stress (strain hardening ratio) is widely different for the two steels. The tests highlight the reduction in ultimate-load capacity and the severely reduced ductility that follows when defects of fabrication and low strain hardening ratio steels occur together.