The influence of weld start reentrant angle on fatigue life determined through analysis and physical testing

The influence of acute toe reentrant angle on fatigue life at a robotic weld start location was investigated both analytically using linear elastic fracture mechanics (LEFM) and through physical testing. 2D LEFM results show no significant change in stress intensity factor (SIF) within a toe reentrant angle range of 60 degrees (acute) to 120 degrees (obtuse). 3D LEFM was used to compare crack growth rates for idealized 60- and 90-degree weld start geometry. Crack propagation was identical for these two cases. Physical fatigue test specimens were created with two distinct toe reentrant angle groups averaging 68 and 103 degrees at the weld start locations. Fatigue failure cycles at three stress ranges for the two groups produced similar stress-life trends. The study concludes that local weld start acute toe reentrant angle change between 60 and 90 degrees does not significantly influence the joint fatigue life under axial loading.