A modified engineering critical assessment method for deeply-embedded cracks in metallic pipelines subjected to large plastic strain. (1st March 2019)

• Record Type: Journal Article
• Authors: Jia, Pengyu; Jing, Hongyang; Xu, Lianyong; Han, Yongdian; zhao, Lei
• Is Part Of: Engineering fracture mechanics. Volume 208(2019)
• Page Start: 171
• Page End: 188
• Publication Date: 2019-03-01
• Subjects: Offshore pipeline -- Deeply-embedded crack -- Surface crack -- The factor F -- Crack tip constraint; Fracture mechanics -- Periodicals; Rupture, Mécanique de la -- Périodiques; Fracture mechanics; Periodicals; 620.112605
• DOI: 10.1016/j.engfracmech.2017.11.024
• Languages: English
• ISSNs: 0013-7944

Abstract

Highlights: It is verified that DNV-RP-F108 is over-conservative to treat deeply-embedded cracks. To reduce the conservatism, a factor F is introduced. The factors which affect F are investigated. A conservative equation of the factor F is proposed. Abstract: The results of three-dimensional finite element analyses indicate that the normalized J -integral values of surface cracks are almost 3 times higher than those of deeply-embedded cracks, provided the sizes of the surface and deeply-embedded cracks are the same. In this paper, we introduce a factor F, which serves as an adjustment factor to reduce the degree of conservatism. The results show that F is the function of the non-dimensional deeply-embedded crack height (2 ae /t ), since F is markedly affected by 2 ae /t . Furthermore, after introducing the factor F, the crack tip constraint of the deeply-embedded cracks is found to be lower than that of the surface cracks, which gives a further conservatism in using the factor F for assessment of embedded cracks.