Tan Na, Lin Liyang, Deng Tao, Dong Yongwu
School of Aeronautics, Chongqing Jiaotong University, Chongqing 400074, China.
The Green Aerotechnics Research Institute, Chongqing Jiaotong University, Chongqing 401120, China.
Polymers (Basel). 2022 Apr 3;14(7):1458. doi: 10.3390/polym14071458.
Residual stress is generated during the production process. It can significantly affect the mechanical performance of pressurized polymer pipes. In this paper, six polyethylene (PE) pipes, including three high-density PEs (HDPE) and three medium-density PEs (MDPE) provided by different suppliers, were tested using a one-slit-ring method to measure the residual stress distribution along the hoop direction. Finite element (FE) simulation and mechanical testing were also employed in an iteration process to obtain the mechanical parameters of the six PE pipes. For the same PE pipe code from different suppliers, the results show that the magnitude of the residual hoop stress can be very different, resulting in different mechanical behaviors. In addition, the results are proposed to explain the scenario that was reported previously, i.e., the different critical quasi-static stress (the time-independent stress) levels of the PE pipes with the same pipe code. Since the quasi-static stress is expected to dominate the long-term behavior of the PE pipes, it is of great importance to carefully consider the effect of the residual stress on the determination of the quasi-static stress.
残余应力是在生产过程中产生的。它会显著影响承压聚合物管道的机械性能。本文采用单缝环法对不同供应商提供的6根聚乙烯（PE）管进行了测试，其中包括3根高密度聚乙烯（HDPE）管和3根中密度聚乙烯（MDPE）管，以测量沿环向的残余应力分布。在迭代过程中还采用了有限元（FE）模拟和力学测试来获取这6根PE管的力学参数。对于来自不同供应商的相同PE管规格，结果表明残余环向应力的大小可能差异很大，从而导致不同的力学行为。此外，还给出了结果来解释先前报道的情况，即相同管规格的PE管具有不同的临界准静态应力（与时间无关的应力）水平。由于准静态应力预计会主导PE管的长期性能，因此在确定准静态应力时仔细考虑残余应力的影响非常重要。
