Cyclic tearing of through wall cracked pipes made of carbon steel

In India like in many other countries also, the nuclear power plants consider earthquake event, in the design of piping components and other structures. In view of it, a series of seven tests have been conducted, on circumferentially through wall cracked straight pipes of 8-inches Sch100 size, made of SA333Gr.6 Carbon steel and subjected to reversible cyclic bending. All the tests have been conducted in four point bend configuration, at room temperature, under quasi-static i.e. slow loading rates and the dynamic effect is not considered. In this study, crack growth by both, fatigue and static fracture have been considered. The fatigue crack growth has been evaluated using, Dowling's J integral (based on the loading branch of cycle) along with the extrapolated high cycle fatigue law (Paris Law). The static crack growth has been calculated cycle by cycle from the monotonic J-R curve and a new proposed J'-integral which accounts for the cyclic damage