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基于粘弹性损伤模型的聚乙烯管材慢速裂纹扩展机理研究

批准号51575480 学科分类机械结构损伤、疲劳与断裂 ( E050401 )
项目负责人郑津洋 负责人职称教授 依托单位浙江大学
资助金额64.00
万元
项目类别面上项目 研究期限2016 年 01 月 01 日 至
2019 年 12 月 31 日
中文主题词粘弹性;损伤模型;聚乙烯;慢速裂纹扩展;失效机理
英文主题词viscoelastic;damage model;polyethylene;slow crack growth;failure mechanism

摘要

中文摘要 随着我国经济的高速发展,作为国民经济血管的油气管道以年均10%以上的速度飞速增长。聚乙烯管已广泛应用于油气输送。据统计,新铺设的城市燃气管道90%以上均使用聚乙烯管。慢速裂纹扩展是聚乙烯管材最主要失效模式,因而聚乙烯管材耐慢速裂纹扩展能力是衡量管材性能的最重要指标。然而,目前国内外对聚乙烯管材耐慢速裂纹扩展能力的评价仍以实验为主。对慢速裂纹扩展的失效机理,尤其是聚乙烯管材在受载后局部应力应变关系变化以及应变能的转移规律,尚无深入理论探讨。本项目拟通过理论分析和有限元数值模拟相结合的方法研究聚乙烯管材慢速裂纹扩展的力学机制。基于连续损伤力学和内聚力理论,建立包含时间相关损伤因子的聚乙烯内聚力本构模型,采用扩展有限元方法(XFEM)研究慢速裂纹扩展断裂过程,通过管材的切口蠕变实验验证并修正模型参数。采用超声相控阵实时成像检测技术观测静液压实验,对比预测结果,进一步验证模型的有效性。
英文摘要 With the rapid development of the economics, as its “lifeline”, pipelines used for transporting oil and nature gas are also increasing with a speed of 10% per year. Polyethylene (PE) pipe has been found widely used in gas and oil distribution. According to the statistics, 90% of newly-built urban gas pipelines are PE pipes. Slow crack growth (SCG) is the main failure mode of PE pipe. Hence the ability to resist SCG is an important index to characterize the property of PE pipe. However, the measurement of this ability both at home and abroad is mainly conducted through experimental methods. The failure mechanism of SCG in PE pipe material, especially the variation of stress-strain relation and the transfer rule of strain energy in local region after loading, is still not well known in the aspect of theory.In this project, finite element numerical simulation, combined with theoretical analysis, will be used to study the mechanics of SCG in PE pipe material. Based on the continuum damage mechanics and cohesive zone model, a PE cohesive constitutive model including time-independent damage factor will be established. Then the extended finite element method (XFEM) will be utilized to investigate the fracture process of SCG. Meanwhile, notched creep tests for PE pipe will be conducted to verify and modify the analyzed model. Furthermore, ultrasonic phased array real-time imaging inspection technique will be used to monitor the hydrostatic test, and then a comparison will be made between the monitored test results and the predicted model results to validate the established model.
结题摘要

成果

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