Reliability Analysis of Crack Arrest in Ductile Fracture of Pressure Pipeline
In order to ensure the safe and stable operation of pressure pipelines,the calculation meth-od of crack arrest probability of a single steel pipe is established by combining the normal distribution probability density function.The crack arrest toughness value of the pipeline is modified based on the BTC method and the CSM formula.The crack arrest reliability of the whole pipeline is investigated un-der the influence of corrosion rate,and the failure time of the pipeline under different crack expansion ranges is analyzed.Finally,the results of ductile fracture risk and stress failure risk are compared.The re-sults show that the crack arrest probability of a single steel pipe can be improved by increasing the mean value of Charpy impact energy.At a corrosion rate of 0.38 mm/a,the failure life of pipelines that meet the reliability standards for 8 steel pipes is 15.2 years,and the failure life of pipelines that meet the reli-ability standards for 5 steel pipes is 15.8 years.The risk of crack ductile fracture is greater than that of stress failure,and the crack propagation of pipelines in high corrosion areas should be paid more atten-tion.The research can provide a practical reference for the formulation of technical indicators for pipe manufacturing and the failure analysis of in-service pipeline operation.
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