Ductile fracture assessment of X65 steel using damage mechanics

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 at simulation level. In this work, the possibility to predict accurately ductile rupture in X65 class steel for offshore application, using a CDM model, is shown. The procedure for material and damage model parameters identification is presented and applied to X65, customer grade steel. Then, damage model predictive capabilities have been validated predicting ductile crack growth in SENB and SENT fracture specimen.