Structural integrity assessment of a 5CT P110 steel riser pipe according to BS 7910:2013 standard

Abstract In this work we performed a structural integrity assessment of a riser pipe made of a material with a novel application, the API 5CT P110 steel, with superficial semi-elliptical cracks in the longitudinal position. The behavior of different crack size on a pipe under specific boundary conditions and pressure loads was studied. With the Finite Element Method, the Stress Intensity Factors along the crack front were obtained and compared with the Stress Intensity Factors calculate by the analytical approach of BS 7910:2013 standard. Afterwards, the fracture toughness of API 5CT P110 steel was obtained through CTOD tests to plot a specific Failure Assessment Diagram according the Option 1 of BS 7910:2013, in order to determine the acceptability of the cracks. The critical crack depths in the studied conditions were 14.2 mm according to the analytical approach of BS 7910:2013 standard and 15.5 mm according to FEM analysis.