1999 Volume 42 Issue 4 Pages 610-617
More than 80 fatigue tests under fluctuating internal pressure are carried out on line pipes with a gouge in a dent in the longitudinal direction to develop a systematic database of fatigue behavior of pipelines. Unpressurized pipe specimens of different grades, diameters and wall thicknesses are first dented and then gouged prior to fatigue tests. This study clarifies that fatigue life(Nf), is dependent on dent depth(d), gouge depth(t)and hoop-stress amplitude(⊿σ)according to a power law Nf=c(d/D)α(t/T)β(⊿σ/E)γ, where c, α, β and γ are coefficients, D is diameter, T is wall thickness and E is Young's modulus. No obvious effects due to defect length and mean hoop stress are detected on fatigue life.