含局部减薄缺陷压力管道承载能力研究

The Study on Load Capacity of Pipe with Local Wall Thinning Defects Under Pressure

局部减薄缺陷会降低压力管道的承载能力,影响管道的安全运行。通过应力强度评定、极限载荷分析及安全评定标准三方面对含局部减薄缺陷压力管道的承载能力进行系统研究,研究了缺陷尺寸(缺陷相对轴向长度,缺陷相对环向角度,缺陷相对深度)对许用载荷、极限载荷和安全评定载荷的影响规律。结果表明,在内压作用下,缺陷相对深度对管道的承载能力影响最大,缺陷相对轴向长度次之,缺陷相对环向角度的影响最小。对比分析发现许用载荷和安全评定载荷基本吻合,极限载荷值高于许用载荷值34.92%左右;许用载荷与安全评定载荷的比值会在一定范围内波动,存在缺陷尺寸相关性;极限载荷值与许用载荷值的比值和局部减薄缺陷的尺寸无关。相对于极限载荷,许用载荷、安全评定载荷是安全的,符合工程应用的要求。

The local wall thinning defect will reduce the load carrying capacity of pressure pipe,and affect its safe operation.Based on stress strength assessment,limit load analysis and safety assessment standard,the load carrying capacity of pipe with local wall thinning defect was systematically studied. The effects of defect sizes(the relative axial length,the relative circumferential angle and the relative depth) on allowable load,limit load and safety assessment load were discussed. The results show that the most critical factor on the load carrying capacity is the relative depth,and the second one is the relative axial length. The least influence factor is the relative circumferential angle. Based on the comparisons among three methods,the allowable load agrees with the safety assessment load,and the limit load is higher than the allowable load about 34.92%.The ratio of the allowable load and the safety assessment load fluctuates within a certain range,which is related with the defect’s size. The ratio of the limit load and the allowable load is independent of the defect’s size. The allowable load and the safety assessment load are conservative with respect to the limit load,which meets the requirement of engineering application.