Stress Intensity Factor Analysis and Fatigue Behavior of A Crack in The Residual Stress Field of Welding

This paper deals with the behavior of a crack in the residual stress field induced by the butt weld in a wide plate. It is known that the distribution form of residual stress has similarities regardless of the welding process, although the size and the magnitude of the residual stress depend largely on the welding process. Stress intensity factor and stress redistribution induced by the crack extension were calculated for a crack with arbitrary length and location. The stress redistributions caused by crack extension obtained by the present analysis showed good agreement with the experimental data. Fatigue crack propagation behavior in the residual stress field reported by Glinka was also examined from ΔK point of view. The effect of residual stress on the fatigue crack propagation rate is considered to be the effect of varying mean stress. It was shown that fatigue crack propagation rate is estimated by the following equation with reasonable accuracy.
da/dn=CΔF^α(1+ σ₀/Δσ F_res)
In the above equation, material constants C and α of Paris’s law are experimentally obtained by using specimens without the weld joint.