PARAMETERS AFFECTING THE BUCKLING AND POST-BUCKLING BEHAVIOUR OF HIGH STRENGTH PIPELINES

摘要

Using the finite element methods, a parametric study was conducted to examine the influence of pipeline diameter, internal pressure, girth weld offset misalignment amplitude and modeled length on the local buckling of high strength pipelines. The numerical procedures were calibrated from full-scale tests on high strength pipelines subject to internal pressure and end rotation.The peak moment decreased with increasing pressure and girth weld offset misalignment amplitude. The limit curvature increased with increasing pressure and decreased with increasing girth weld offset misalignment amplitude.The effect of reducing the modeled pipeline segment length, from 5.5 D to 3.5 D, was to increase the limit curvature at the peak moment and to delay the onset of nonlinear ovalization response to higher curvature amplitudes.The influence of girth weld offset misalignment on the local buckling response was examined in terms of a strain capacity reduction parameter known as the girth weld factor. This study has determined current practice, based on DNV OS-F101 standard, was appropriate; moreover, the potential for reduction in this conservative approach is identified.