Fracture mechanics-based design and reliability assessment of fillet welded cylindrical joints under tension and torsion loading

• Cylindrical shafts connected by differently-shaped fillet welds are analyzed.
• The mode-I, II and III stress intensity factors (SIFs) are calculated as a function of the lack of penetration ratio.
• Normalized SIFs decrease with decreasing lack of penetration size for all modes.
• The higher the fillet weld throat cross section, the lower the SIFs of the LOP cracks.

Cylindrical fillet-welded joints under tensile and torsion loads are analyzed to investigate the sensitivities of weld geometry-related parameters, such as size of lack of penetration, weld shape and weld root radius, on the fracture response of the joint. SIFs decrease with decreasing lack of penetration size and that having a convex weld shape yields better fracture response. The longer the penetration edge on the shaft the better the fracture response. Weld root radius does not have significant effect on the fracture response of LOP crack. Lower convexity radius resulted in lower mode-I and mode-III SIFs due to more material around the crack tip region in the fillet weld throat.