Comportamiento Mecánico de Grietas No Coplanares en Tubos Aplicando el Método de los Elementos Finitos

Planar-type cracks formed at different depths within tube walls, which are generally caused by hydrogen-induced cracking were analyzed. Modeling was carried out on the interaction of pressurized cracks contained within the tube wall with internal pressure prior to their coalescence, varying the radius of the defects. The finite elements method was applied under non-linear conditions of the material following the isotropie hardening law and considering the properties of the material (API 5LX52). The results suggested the evolution of stress fields and deformations in the crack tips area as a function of the pressure of the defect. Defects of less than 38.1 mm resist a pressure of 70 to 124 MPa, and those larger than 63.5 mm severely affect the mechanical integrity. The function of the critical pressure supported by symmetrical cracks is of the potential type, and this pressure produces the interaction which plastifies the region among the cracks, prior to stepping.