X80管道凹痕缺陷失效准则对比分析

为了提高油气管道凹痕缺陷安全评价的准确性，将金属材料的韧性失效准则应用到管道凹痕的损伤评价中。以X80管道凹痕为例，采用有限元法计算不同工况下3种失效准则的管道损伤量并作对比分析。研究发现，管道损伤量随凹痕深度的增加而增加；当凹痕深度大于6%管道外径时，管道损伤量的增长速率减小。其中，Oyane韧性断裂准则计算出的损伤量最大，临界空穴扩张比判据理论次之，而X-W损伤失效准则计算的损伤量最小。此外，通过研究凹痕缺陷的类型对损伤量的影响发现，Oyane韧性断裂准则能更好地反映管道凹痕区域的应力集中。研究结果表明，Oyane韧性断裂准则更适合用于深度较大以及不同种类的管道凹痕缺陷的评估。为进一步研究韧性失效准则在管道凹痕评价中的应用提供参考。

A Comparative Analysis on Failure Criteria of X80 Pipeline Dent Defect

In order to improve the accuracy of safety evaluation of oil and gas pipeline dent defects, the ductile failure criteria of metal materials are applied to the damage evaluation of pipeline dents. Taking X80 dented pipeline as an example, the pipeline damage of three failure criteria under different working conditions was calculated by finite element method and a comparative study was made. It was found that the pipeline damage increases with the increased dent depth; when the dent depth is greater than 6% of the pipeline diameter, the growth rate of pipeline damage decreases. The damage calculated by Oyane ductile fracture criterion is the largest, the critical void expansion ratio criterion is the second, and the X-W damage failure criterion is the smallest. In addition, it was found that the Oyane ductile fracture criterion can better reflect the stress concentration in the dent area by studying the influence of the dent geometry defect on the damage amount. The results show that the Oyane ductile fracture criterion is more suitable for the evaluation of deep and different pipeline dent defects. It provides a reference for further research on the application of ductile failure criterion in pipeline dent evaluation.