Volume 3, Issue 6 (June 2006)
An Experimental and Numerical Study of the Fracture Strength of Welded Structural Hollow Section X-Joints
The effect of the geometry and material properties on the fracture strength of welded X-joints fabricated from structural hollow section (SHS) profiles has been studied experimentally and by using nonlinear finite element analysis (FEA). The current paper focuses on four joints tested at −40°C. This was one part of an extensive series of laboratory experiments performed at temperatures +20°C… −60°C. At sub-zero temperatures the primary fracture mode was mainly ductile followed by final brittle failure. The radius and material properties in the corner area of a SHS are dependent on the fabrication method of the SHS. In cold-formed sections the corner radius is typically large and the yield strength is greater than the nominal yield strength of the base material. This bigger corner radius can provide different stiffness and load carrying capacity as compared to joints fabricated from hot-formed sections. Numerical simulation and experimental tests focused on the importance of this corner effect and the separate role geometry, yield strength, and fracture toughness on the total fracture strength of the joint.