含缺陷聚乙烯管材蠕变损伤行为及使用寿命预测方法研究  

Research on Creep Damage Behavior and Lifetime Estimation Method of Defects PE Pipes

作　　者：王志刚 杨波 李仕平 翟伟 黄国家 WANG Zhi-gang;YANG Bo;LI Shi-ping;ZHAI Wei;HUANG Guo-jia(Guangzhou Special Pressure Equipment Inspection and Research Institute,Guangzhou 510663,China)

机构地区：[1]广州特种承压设备检测研究院,广东广州510663

出　　处：《塑料工业》2020年第11期90-93,共4页China Plastics Industry

基　　金：国家市场监督管理总局科技项目(2019MK159);广东省市场监督管理局科技项目(2018PT09)。

摘　　要：通过建立全切口蠕变试验(FNCT)研究聚乙烯管材的蠕变损伤行为,结合高聚物材料线弹性断裂力学的Paris幂律积分模型,实现在管内压作用下,含椭球形初始裂纹缺陷的聚乙烯管材的使用寿命预测。为了减少试验温度T对评价结果的影响,通过建立温度-破坏时间等效FNCT试验,得到在同一载荷F(8 MPa)、不同温度T(60~80℃)条件下,环形缺口试样慢速裂纹增长过程中的裂纹张口位移速率(dCOD/dt)与应力强度因子(KI)的对应关系,最终外推得到含缺陷聚乙烯管材实际运行环境下的使用寿命(tlife)与管内压(σhoop)的关系曲线,该曲线与传统SEM方法得到的管材长期静液压曲线相近,试验结果证实了该方法的有效性。The full notch creep test(FNCT)method was established to study the creep damage behavior of polyethylene pipes,and combining the Paris power law integral model of linear elastic fracture mechanics of polymer materials,the lifetime estimation method of polyethylene pipes with ellipsoidal initial crack defects was achieved under internal pressure.In order to reduce the influence of test temperature T on the evaluation results,the temperature-failure time equivalent FNCT test was established to obtain the relationship between the opening displacement rate d COD/d t and the stress intensity factor K I of ring notch specimen in its slow crack growth stage,which under the same load F(8 MPa)and different temperature T(60~80℃).Finally,the relation curves between the lifetime(t life)and the internal pressure(σhoop)of the defective polyethylene pipe in the actual operation process was obtained,and it was similar to the long-term hydrostatic curve obtained by the traditional scanning electron microscope(SEM)method,the test results confirmed the effectiveness of the proposed method.

关 键 词：全切口蠕变试验 蠕变损伤 线弹性断裂力学 使用寿命 管内压 

分 类 号：TB301[一般工业技术—材料科学与工程]