含凹陷在役管道应变预测模型

Prediction Model of Strain for Pipelines in Service with Dent Defect

针对在役含凹陷管道的安全评价,准确预测凹陷管道应变至关重要,然而现有美国机械工程学会(American Society of Mechanical Engineering,ASME)标准中的凹陷管道应变预测公式并未考虑管道运行内压对管道应变的影响。因此,建立了考虑内压作用的含凹陷管道有限元模型,研究了不同凹陷深度下,压头半径、管材性能、管道内压、管道壁厚、管道直径对管道最大等效塑性应变(ε_(0)^(max))的变化规律,提出了一种适用于在役凹陷管道的应变预测模型。结果表明:相对凹陷深度为6%时,管道内压从0 MPa增加到8 MPa,管道凹陷处ε_(0)^(max)增长幅度为50.26%。所提出的ε_(0)^(max)预测模型与有限元结果相比,平均误差为5.32%;与文献测试结果相比,最大和最小误差分别为12.51%和4.74%;该预测模型可以为在役凹陷管道安全评估提供一定的参考。

It is very important to accurately predict the strain of dented pipelines accurately for the safety evaluation of pipelines in service with dent defect.However,the strain prediction formula of dented pipe in existing American Society of Mechanical Engineering(ASME) standard neglects the influence of internal pressure on the strain of pipe.Therefore,a finite element model of dented pipe was established with internal pressure load,the influence of indenter radius,material property,pipe internal pressure,pipe wall thickness and pipe diameter on the maximum equivalent plastic strain(ε_0~(max)) of the pipe at different dent depths were studied,a strain prediction model for pipelines in service with dent defect was proposed.The results show that when the relative dent defect depth is 6%,the internal pressure of the pipeline increases from 0 MPa to 8 MPa,and the ε_0~(max) increase rate is 50.26%.The average error of ε_0~(max) prediction model is 5.32% compared with the result of the finite element model.The maximum error and minimum error are 12.51% and 4.74% compared with the result of test results in the literature.The prediction model provides some reference for safety evaluation of pipeline in service.