初始几何缺陷对管道极限承载力影响研究

Effects of initial imperfections on pipeline capacities

初始几何缺陷被认为是影响管道极限承载力和稳定性的重要因素,但是大部分的管道力学特性研究都没有考虑初始缺陷的影响。基于管道几何尺寸测量机,获得管道的壁厚和直径沿轴向以及环向的分布规律。据此建立了四个三维实体有限元模型,分别为完好管道模型、只考虑直径缺陷的管道模型、只考虑壁厚缺陷的管道模型以及考虑所有缺陷的管道模型。分析了初始缺陷对管道的极限内压承载力、极限轴力承载力和极限弯矩承载力的影响。结果表明,直径缺陷对管道的极限内压承载力影响较大;壁厚缺陷对管道在复杂荷载作用下的极限弯矩承载力影响较大。

Initial geometry imperfections have been regarded as an important factor which affects both ultimate capacities and stability of steel pipelines. However, the effect of initial imperfections is often ignored in pipeline design. A pipeline geometry measuring machine is used to obtain the distributions of wall thickness and diameter of a pipe along the axial and the hoop directions. Then, based on these measured data, four three-dimensional finite element models such as the perfect pipeline model, the model containing diameter defect, the model containing thickness defect and the model containing all defects are established, respectively. Finally, the effects of initial imperfections on the internal pressure capacity, the axially compressed capacity and the bending capacity are analyzed. From the results, the imperfections due to diameter has a great effect on the internal pressure capacity; while thickness imperfection has a remarkable influence on the pipeline bending capacity under combined internal pressure and axial compression.