Local buckling failure analysis of high strength pipelines containing a plain dent under bending moment

摘要

This work investigated the local buckling failure of high-strength and large-diameter pipelines containing a dent under bending moment. An improved three-dimensional numerical model was developed by considering the multiple nonlinearities of pipe geometry, material and the boundary conditions. The effect of yield strength and strain hardening parameters of pipeline steel on the critical buckling load at the dent was analyzed in detail. The results show that, the critical buckling moment of the pipeline decreases with the increase of n. However, when the internal pressure is low, the influence of internal pressure on the critical buckling moment is limited, and the hardening exponent affects the critical buckling moment only when n < 24. The greater the internal pressure, the faster the critical bending moment decreases with the strain hardening exponent, especially when the circumferential stress of the pipeline exceeds the yield strength of the steel. The sensitivity analysis of the size parameters of dents indicates that the large and deep dent can significantly reduce the bending moment resistance of a pipeline.