Lateral buckling of pipelines due to internal pressure: A geometrically nonlinear finite element analysis

This work presents an analysis of the lateral buckling of pipelines triggered by internal pressure. Geometrical imperfection amplitudes and friction of pipeline-soil are studied concerning their influence on the critical load and on the post-buckling configuration. To perform the analyses, numerical models are developed using geometrically-exact 3D Timoshenko beam finite elements, which may undergo large displacements and finite rotations. The interaction between the pipeline and the soil is simulated through a contact model. Geometrical imperfections are addressed by imposing prescribed displacements and considering uneven surfaces to represent the soil. The latter, by the way, allow to input concomitant vertical and lateral imperfections to the models. Varying vertical and lateral imperfection amplitudes and soil friction coefficients, the results show that all the parameters together influence the lateral buckling concerning critical loads and shape, order and amplitude of post-buckling configurations of the pipeline. Comparisons with analytical models are also presented.