In this study, a novel fundamental model for the multiple crack initiation behavior of polymer pipes transporting fluids with strong oxidizing agents was proposed. Because the oxidant diffuses into the polymer medium with consumption by oxidation, a volumetric sink of the diffused oxidant was considered. The degradation kinetics of the polymer pipes were modeled by diffusion using the reaction equations. To compare the released energy with the crack initiation, Green's function for the stress intensity factor of various crack numbers, sizes, and standard dimension ratios (SDRs) was developed. The number of crack initiations and durations were successfully simulated using potential energy analysis with cracking. At a relatively low internal pressure in an oxidative environment, multiple cracks were estimated with a proper scale of the crack length. Instead, it was predicted that one main crack would be initiated at a higher level of internal pressure. In addition, the knee points representing the slope change of the internal pressure-lifetime plot were shown between these different failure modes, in agreement with previous observations. The experimental results of sustained hydrostatic pressure tests of polymer pipes under chlorinated water can be accurately simulated by the proposed model.

在这项研究中，提出了一种用于输送具有强氧化剂的流体的聚合物管道的多重裂纹萌生行为的新基本模型。由于氧化剂通过氧化消耗扩散到聚合物介质中，因此考虑了扩散氧化剂的体积汇。聚合物管的降解动力学通过使用反应方程的扩散来建模。为了将释放能量与裂纹萌生进行比较，开发了针对各种裂纹数量、尺寸和标准尺寸比 (SDR) 的应力强度因子的格林函数。使用开裂势能分析成功地模拟了开裂的数量和持续时间。在氧化环境中相对较低的内部压力，使用适当的裂纹长度比例估计多个裂纹。相反，据预测，一个主裂纹将在更高的内部压力水平下开始。此外，在这些不同的失效模式之间显示了代表内部压力-寿命曲线斜率变化的拐点，与之前的观察结果一致。所提出的模型可以准确模拟氯化水下聚合物管道的持续静水压力试验结果。