Stress intensity factor expression for center-cracked butt joint considering the effect of joint shape

In this paper, the stress intensity factor (SIF) expression for center-cracked butt joint under tensile load was derived and the SIF differences with or without considering weld reinforcement were discussed. For the sake of discussion, the curve of weld reinforcement is regarded as circle, the reinforcement circle and the other two weld toe smooth transition circles are assumed to be tangential. The influences of such joint shape parameters as weld width, weld toe smooth transition radius and base metal thickness on SIF were also studied. The relationship between SIF for center-cracked butt joint and its shape parameters was finally obtained based on the integration of analytical and finite element method. It showed that it is wrong to perform failure analysis on center-cracked butt joint without considering weld reinforcement, the derivation method of SIF developed here can be use to design the shape of the butt joint with defects under static loads or fatigue condition.

► We give an accurate stress intensity factor expression of center-cracked butt joint. ► We propose a new method to obtain the stress intensity factor expression of joint. ► Increasing weld width and reinforcement will decrease stress intensity factor value. ► The stress intensity factor value can guide joint shape design efficiently.