Parametric Analysis of Upheaval Buckling of Submarine Pipe-in-pipe Systems

Improper operation in the installation process will make the pipeline an initial local upheaval.The initial local imperfection is the potential factor to induce the upheaval buckling.The axial compressive force is the primary cause of pipeline buckling.The submarine pipeline may be liable to upheaval buckling caused by rise in axial force due to temperature changes.The interaction between the inner pipe and the outer pipe is complicated and the complex structure of PIP system makes the global buckling difficult to tackle in theory analysis.A finite element model is presented to analyze the upheaval buckling of PIP systems with initial local imperfections.The impacting trend of key parameters such as the initial out-of-straightness and annulus is obtained.Furthermore,these calculation results provide the actual projects in china a reference value for the upheaval buckling analysis on subsea PIP system.