带腐蚀缺陷管道的安全性评价方法研究

Research on Methods of Safety Evaluation for Pipelines with Corrosion Defects

为了选择合适的安全性评价方法准确评估带腐蚀缺陷管道,结合有限元分析方法从膨胀系数、流变应力和失效压力三个方面对带腐蚀缺陷管道的安全性评价方法进行对比研究,研究结果表明,膨胀系数随轴向缺陷增长而增大,对各种评价结果的影响也随之增大;随着钢级的提高,各种评价方法的流变应力分化逐渐得到缓和,虚拟屈服应力趋同;在不同管道外径、壁厚、缺陷深度、缺陷长度、屈服强度和拉伸强度下,SY/T6151-1995标准的整体失效压力偏小,评价结果最为保守,会造成巨大的浪费;DNV RP-F101标准的评价结果最为冒险,很容易发生安全事故;而ASME B31G-2009标准、API579-2000标准和有限元分析法的评价结果相对适中,可较多应用于对管道的实际评估。

In order to select the appropriate safety evaluation method to assess the pipelines with corrosion defect accurately.Comparison and analysis about evaluation method was carried out by using expansion coefficient,rheological stress and failure pressure combined with finite element analysis method.Results demonstrate that expansion coefficient and effects on evaluation results increased by the increasing corrosion axial length;With the improvement of steel grade,the differentiation of rheological stress in every evaluation methods decreases,there has been value convergence in virtual yield stress;under different pipe outside diameter,wall thickness,depth,length of defects,yield strength and tensile strength,it reveals that the evaluation results of SY/T6151-1995 standard is the most conservative rules,huge waste may be caused.Evaluation results of DNV RP-F101 standard is a extreme adventure,it easily leads to accidents.The evaluation results of ASME standard B31G-2009,API standards 579-2000 and FEM analysis is relatively moderate,they will more practical to pipeline assessment.