Issue 38

N.O. Larrosa et alii, Frattura ed Integrità Strutturale, 38 (2016) 266-272; DOI: 10.3221/IGF-ESIS.38.36 271 (geometry independent) and couples the loading history (stress-strain) with phenomenological features of the microstructural fracture mechanism (material + loading history dependent). In addition, a Two Parameter Fracture Mechanics approach has been applied to match the constraint conditions present in a defective structural component to those present in the test specimens. By doing this, the J-Q approach allows an improved assessment of the fracture resistance of the component, by using the fracture resistance of the test specimen with similar constraint conditions to reduce over-conservatism in fracture assessments C(T), J 0.2 =477.62 kJ/m 2 SE(T), J 0.2 =653.28 kJ/m 2 MBL, T=0 J=653.28 kJ/m 2 , internal pressure (P) J=477.62 kJ/m 2 , internal pressure (P) J=653.28 kJ/m 2 , pure bending (M) J=477.62 kJ/m 2 , pure bending (M) 1 2 3 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 Q PIPE (M) Q PIPE (P) Q SE(T) API X65 r  0 /J  /  0 Q C(T) Figure 4 . Normalized crack-opening stress distribution for the different components. A CKNOWLEDGEMENTS he authors would like to acknowledge the funding and technical support from BP through the BP International Centre for Advanced Materials (BP-ICAM) which made this research possible. R EFERENCES [1] ASTM E1820-06a, American Society for Testing and Materials. Standard Test Method for Measurement of Fracture Toughness (2001). [2] ESIS P2-92: Procedure for Determining the Fracture Behaviour of Materials (1992). [3] DNV-RP-F108, Det Norske Veritas: Fracture control for pipeline installation methods introducing cyclic plastic strain (2006). [4] Anderson, T.L., Fracture Mechanics: Fundamentals and Applications. CRC press, Taylor & Francis, Boca Raton, Florida, USA, (1995). [5] Cravero, S., Ruggieri, C., Correlation of fracture behaviour in high pressure pipelines with axial flaws using constraint designed test specimens - Part I: Plane-strain analyses, Engineering Fracture Mechanics, 72 (2005) 1344–1360. [6] Oh, C.-S., Kim, N.-H., Kim, Y.-J., Baek, J.-H., Kim, Y.-P., Kim, W.-S., A finite element ductile failure simulation method using stress-modified fracture strain model, Engineering Fracture Mechanics, 78 (2011) 124–137. [7] Han, J.-J., Kim, Y.-J., Ainsworth, R.A., Constraint effects in ductile fracture on J -Resistance curve for full-scale cracked pipes and fracture toughness testing specimens. American Society of Mechanical Engineers, Pressure Vessels and Piping Division, 5 (2014). [8] O’Dowd, N.P., Shih, C.F., Family of crack-tip fields characterized by a triaxiality parameter-I: Structure of fields, Journal of the Mechanics and Physics of Solids, 39 (1991) 989–1015. T