Analysis on collapse behavior of sandwich pipelines considering the eccentric effect

Compared with the traditional single-layer pipelines, the sandwich pipelines have a more complex structural configuration, and the problem of non-uniform filling thickness in the sandwich layer may occur easily in the manufacturing process, which could result in the decentraction of the inner and outer pipes, adversely affecting the external pressure bearing capacity of the pipelines. Therefore, a numerical model for the collapse strength of the eccentric sandwich pipelines under the external pressure was established with the finite element software ABAQUS, and the model was also verified with the experimental results of the existing literatures. In addition, the parametric modeling of the eccentric sandwich pipelines was realized with the Python script program, and the influence of the eccentricity with different initial ovality, inner pipe diameter to thickness ratio, material strength and interlayer bonding conditions on the compressive strength of the sandwich pipelines was studied. The results show that, with the increase of eccentricity, the collapse strength of the sandwich pipes decreases significantly. As the initial ovality increases, the collapse strength of the sandwich pipes decreases obviously. In the research condition, when the eccentricity is greater than 4 mm, the change of the diameter to thickness ratio of the inner pipe, the pipe material strength and the interlayer bonding conditions have more obvious effects on the collapse strength of the sandwich pipelines with the increase of eccentricity. The research results could provide reference for the engineering application of sandwich pipelines.