科研之友
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摘要
This paper investigates buried gas pipelines impacted by an excavator bucket, in addition to the digging load driven by the hydrocylinder of an excavator, and the impact caused by liquid pressure oscillation and the inertial force of the excavator system. These were taken into account for the impact load subjected by the excavator bucket teeth, and the dynamic load coefficient was suggested theoretically. Then the dynamic stress distribution of the buried gas pipeline and corresponding digging limiting load were evaluated by using the strength criterion and the LS-DYNA commercial finite-element software, in which two excavation sections of perpendicular to and parallel to the longitudinal direction of pipeline were detected respectively. Furthermore, cracks exist in the actual pipeline, and the numerical analysis model of the high-pressure gas pipeline with an elliptical crack at the inner surface was established. The limit digging load while the crack existed was determined by the theory of dynamic fracture and compound fracture criterion, which was 20% lower than that without cracks. The numerical analysis method in this article has certain reference value to the design, construction, and risk assessment of a buried gas pipeline.
