A semi-analytical approach to elastic-plastic buckling analysis of pipes with asymmetric local wall thinning

摘要

The buckling behavior of the corroded submarine pipeline subjected to external pressure is analyzed. A semi analytical approach for the elastic-plastic buckling pressure of a pipe with asymmetric local wall thinning is developed. Based on this method, the buckling pressure is calculated by solving the characteristic equations of different buckling modes. When the depth of internal and external local wall thinning is equal, the semi analytical approach can be used to determine the buckling pressure of pipe with symmetrical corrosion defect, and it also can be used for the buckling analysis of the pipe containing only an internal or external corrosion defect by making the external or internal defect depth being zero. Then, the accuracy and necessity of the proposed approach are verified by comparing with the finite element modeling, experimental tests and previous equations, respectively. The effects of various parameters, viz., radius-to-thickness ratio, defect angle and depth, corrosion defect position, and yield stress, on the buckling pressure are investigated in details. The applicability of the semi-analytical approach is discussed under the condition of both internal and external pressure and different defect lengths. Finally, the post-buckling behavior of corroded pipe is investigated in details.