Fatigue analysis of square-to-square tubular T-joint with surface crack

Ultimate strength and fracture behaviour of cracked welded square hollow section T-joints

“…The experimental observation (Chiew et al, 2003) shows that the fatigue crack is propagating on a 3-D curved surface formed inside the thickness of the chord.…”

“…Because of the geometrical difference between the two types of tubular joints, the fatigue behaviour of the SHS joints is quite different from that of CHS joints (Chiew et al, 2003). The fatigue crack generally initiates from one of the brace corners in the chord face where the hot spot stress is located.…”

“…After the crack has propagated through the chord thickness, the geometry of the joint is not symmetric, and the stress distributions around the two crack tips are different, and hence the fatigue crack propagation rates of the two crack tips are different too, resulting in an unsymmetrical fatigue crack propagation. Furthermore, the crack shape is inclined and slightly curved (Chiew et. al., 2002).…”

“…Because the geometry of the SHS and RHS joints is quite different from the CHS joints, especially the existence of the brace corner, the fatigue crack shows different curvature , and there is no benchmark of crack curvature for SHS joints available in the literature. Based on the experimental data carried out recently (Chiew et al, 2003), the geometry of these fatigue cracks under the weld toe in the SHS joints will be discussed in the following sections.…”

“…There has already been extensive research being carried out on the prediction of stress intensity factor (SIF) of cracked tubular joints in the past decades (Du and Hancock, 1989; Chong Rhee et al, 1991; Pook, 1993; Bowness and Lee, 1995; Chiew et al, 2003Chiew et al, , 2004. From the past literature (Yang, 1996), it has been found that an accurate crack modelling is essential in obtaining a reasonable numerical result.…”