APPROXIMATE CALCULATION OF J-INTEGRAL OF PRESSURE PIPES WITH CIRCUMFERENTIAL SURFACE CRACK

The estimation methods (SC.ENG1 and SC.ENG2) of J-integral for pipes with circumferential surface crack are discussed in detail and the 3D elastic-plastic finite element model for circumferentially surface-cracked pipe is established to testify the feasibility of above methods. The 3D elastic-plastic fracture analysis is conducted to study the distribution of J-integral along the front of surface crack, and the effects of pipe material with different yield plateau on J-integral values are discussed. The feasibility of these J-integral estimation methods for pipe steel with different yield plateau used in China is also discussed in detail.