Issue 42

G. Testa et alii, Frattura ed Integrità Strutturale, 42 (2017) 315-327; DOI: 10.3221/IGF-ESIS.42.33 315 Strain capacity assessment of API X65 steel using damage mechanics Gabriel Testa, Nicola Bonora, Domenico Gentile, Andrew Ruggiero, Gianluca Iannitti University of Cassino and Southern Lazio, Italy gabriel.testa@unicas.it, http://orcid.org/0000-0001-2345-6789 Antonio Carlucci SAIPEM SA, Italy antonio.carlucci@saipem.com Yazid Madi EPF-Ecole d'ingénieurs / MINES ParisTech, France yazid.madi@epf.fr A BSTRACT . Strain-based design for offshore pipeline requires a considerable experimental work aimed to determine the material fracture toughness and the effective strain capacity of pipe and welds. Continuum damage mechanics can be used to limit the experimental effort and to perform most of the assessment analysis and evaluation in a simulation environment. In this work, the possibility to predict accurately fracture resistance of X65 steel using a CDM model proposed by the authors, is shown. The procedure for material and damage model parameters identification is presented. Damage model predictive capability was demonstrated predicting ductile crack growth in SENB and SENT fracture specimens. K EYWORDS . Damage mechanics; Fracture toughness; Strain capacity; Strain- based design. Citation: Testa, G., Bonora, N., Gentile, D., Ruggiero, A., Iannitti, G., Carlucci, A., Madi, Y., Strain capacity assessment of API X65 steel using damage mechanics, Frattura ed Integrità Strutturale, 42 (2017) 315-327. Received: 25.07.2017 Accepted: 22.08.2017 Published: 01.10.2017 Copyright: © 2017 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION ipelines for transporting hydrocarbons are required to operate safely in extreme environments that include low temperature, sour surroundings, high stress and large deformation. In remote areas, such as arctic regions, these systems are exposed to unique environmental conditions not normally present in other regions of the world, which includes ice scours, permafrost thaw and/or frost heave. For buried pipelines, the key design issue is the potential for large bending strain resulting from frost heave and thaw settlement, ice gouging in the shallow waters and severe seismic events [1]. P