Engineering C‐integral and COD estimates for nonidealized circumferential through‐wall cracked pipes at elevated temperature

• Published in: Fatigue & fracture of engineering materials & structures Vol. 42; no. 2; pp. 494 - 503
• Main Authors: Won, Min‐Gu, Kim, Kyunghoon, Huh, Nam‐Su, Kim, Woo‐Gon, Lee, Hyeong‐Yeon
• Format: Journal Article
• Language: English
• Published: Oxford Wiley Subscription Services, Inc 01-02-2019
• Subjects: Axial stress; Bending moments; Circumferences; Crack opening displacement; creep fracture mechanics parameter; enhanced reference stress method; Finite element method; Fracture mechanics; GE/EPRI method; High temperature; Integrals; Internal pressure; Mathematical models; nonidealized through‐wall crack; Norton creep model; Pipes; RCC‐MRx creep model
• ISSN: 8756-758X; 1460-2695
• DOI: 10.1111/ffe.12925

In this study, creep fracture mechanics parameters, C*‐integral and crack opening displacement (COD) rate, are estimated for a nonidealized circumferential through‐wall crack (TWC) in pipes. The GE/EPRI and enhanced reference stress (ERS) methods are employed. As for creep condition, the Norton and RCC‐MRx creep models are considered for secondary and primary‐secondary creep strain, respectively. The bending moment, axial tension, and internal pressure are applied to a pipe with a nonidealized circumferential TWC, as individual loads. Three‐dimensional elastic‐creep finite element (FE) analyses are performed, and the predictions from the GE/EPRI and ERS methods are compared with FE results. For the Norton creep model, both methods show good agreement with the FE results. For the RCC‐MRx creep model, only the ERS method can be used, and it provides accurate predictions comparing with FE results. Based on the comparison results, the use of the present engineering C*‐integral and COD estimation methods for nonidealized circumferential TWC is validated.