Creep crack growth prediction and assessment incorporating constraint effect for pressurized pipes with axial surface cracks

摘要

Creep crack growth life is firstly predicted and assessed by two-parameter concept to incorporate constraint effect for pressurized pipes with inner axial surface cracks. The prediction and assessment results are compared with those based on conventional single-parameter C* and finite element calculations. For shallower and shorter cracks, the life assessments based on single-parameter C* are excessively conservative. To reduce excess conservativity, it is strongly recommended to incorporate constraint effect. With decreasing initial crack sizes, the benefits gained from two-parameter assessments increase. The crack growth profile may also be correctly predicted by two-parameter calculations. The C* calculation of reference stress method leads to extra conservativity. (C) 2016 Elsevier Ltd. All rights reserved.