Finite Element Simulation for Shear Failure of Wrinkled Pipeline

Buried pipelines may be subjected to various complicated combinations of forces and deformations. This may result in localized curvature, strains, and associated deformations in the pipe wall. As a result, wrinkles may form. The wrinkled pipeline may then develop a fracture and even rupture in the pipe wall and lose its structural integrity if it is subjected to further sustained deformation. An NPS 10 field line pipe ruptured due to tearing in the pipe wall in the wrinkle region. It was felt that the wrinkle was subjected to shear deformation that resulted in tearing type rupture. Numerical study using non-linear finite element (FE) method was carried out to study the possible load-deformation history that may cause this type of failure. A detailed FE model was developed and analyzed to study the behavior of a wrinkled pipeline subjected to axial and shear deformation. The study shows that the combination of axial and shear deformations can introduce tearing type rupture in the wrinkle region the way the NPS10 field line pipe ruptured. This paper discusses the FE modeling technique and the results obtained from the FE analysis.