Effects of Geometric Misalignment Caused by Girth Weld on Fatigue Behavior of a Cylindrical Pressure Vessel

The paper presents the results of finite element analysis of a pressurized vessel typically made of steel 1025 and containing the weld misalignment at the cylinder-to-cylinder junction. This misalignment considered in the vessel's structure is because of girth weld that is found in most of the fabrications of such type of structures. Geometric misalignment of 50% of thickness is considered for this particular study. The work evaluates the geometrical effects of misalignment on the fatigue behavior of the pressure vessel to quantify its consequences in term of fatigue life and maximum damage. Finite Element (FE) analysis is performed by the use of ANSYS on one quarter of the structure due to symmetry. A significant effect of misalignment on fatigue life of the cylinder has been found and is presented with maximum anticipated damage in the critical areas.