Crack initiation and growth behaviour of circumferentially cracked pipes under cyclic and monotonic loading

Studies have been carried out on carbon steel pipes to demonstrate the leak before break design criterion and validate the analytical procedures. Fatigue crack initiation, fatigue crack growth rate and fracture resistance behaviour of the pipes have been experimentally and analytically evaluated. The tests have been carried out on pipes of outer diameter 219 and 15.1 mm wall thickness having a part through notch in the circumferential direction. The aspect ratios (2c/a) of the notches were 56, 28 and 18. Comparing the analytical and experimental results has validated analytical procedures. It has been observed that the analytical and experimental results compare well. The fatigue crack growth curve (da/dN similar to DeltaK) obtained from three point bend specimens and pipe tests have been compared with the fatigue crack growth curve in ASME Section XL The comparison shows that use of the ASME curve in analysis of components will give a conservative result in comparison to the curves obtained from the actual pipe tests. Fracture resistance behaviour of the pipe has been observed to be strongly dependent on the load histories to which the pipe has been subjected. (C) 2003 Elsevier Ltd. All rights reserved.