基于非线性黏弹性内聚力理论的钢丝增强塑料复合管粘结界面渐进损伤失效行为及其机理研究

Under the long-term inner pressure loading and the high temperature, bulging deformation and ultimate failure occur in the joint of the polyethylene pipe reinforced by winding steel wires (PSP), which affects the safety of pipeline system. The previous research indicates the interfacial debonding failure in the PSP is the main cause of the PSP joint failure. In this project, the nonlinear viscoelastic property of HDPE matrix and holt melt adhesive resin will be investigated firstly. Then a one-dimensional nonlinear viscoelastic cohesive zone model will be proposed to represent the interfacial mechanical behavior. Based on the finite element simulation and the experimental research, type I and type II interfacial damage evolution of experimental specimen will be analyzed. The interfacial damage initiation criterion and the damage evolution criterion will be proposed. Afterwards, three-dimensional nonlinear viscoelastic cohesive zone model will be derived, and the investigation on the adhesive interfacial mechanical behavior under complicated stress state will be conducted. The influence of the loadings from three directions on the interfacial failure behavior will be analyzed. In the end, long-term mechanical model of PSP will be constructed to analyze the time-dependent interfacial property in PSP structure under different temperatures and long-term inner pressure. The whole failure process of PSP joint will be reproduced using the finite element model, and the mechanism of the adhesive interfacial damage evolution of PSP will be revealed. Subsequently, the life-prediction method of PSP joint will be raised. Eventually, the failure mechanism of the interfacial debonding in the PSP will be revealed through the theoretical method, numerical simulation and experimental research. It will provide a theoretical basis for the damage estimation and the life prediction of PSP joint.

在长时内压和高温的作用下，钢丝增强塑料复合管（简称PSP）接头会发生隆起变形甚至强度失效，严重影响管道系统安全。前期研究表明PSP粘结界面失效是接头失效主要原因。本项目拟从PSP基体高密度聚乙烯（HDPE）与热熔胶的非线性黏弹特性入手，提出一维非线性黏弹性内聚力本构模型表征界面力学性能，结合有限元模拟与试验研究，分析I型/II型单一失效模式下界面损伤失效行为，提出损伤起始与演化准则；扩展三维非线性黏弹性内聚力本构模型，研究复杂应力状态下试样粘结界面力学性能，分析界面三向载荷对其失效行为的综合影响；构建PSP接头长时力学性能模型，分析不同温度、长时内压下PSP钢塑界面性能随时间的变化规律，再现PSP接头失效全过程，揭示PSP钢塑界面损伤失效机理，提出接头寿命预测方法。本项目以理论、模拟与试验结合的方式开展PSP钢塑粘结界面损伤失效行为及其机理研究，为PSP接头损伤评估与寿命预测提供参考。

本项目开展了高聚物基体的粘弹性力学性能研究；开展了单钢丝拉拔模型界面脱粘失效研究，提出了基于反演算法的粘结界面性能评价方法；开展了粘结界面法向失效过程的分析研究工作；分析了不同钢丝埋深、材料温度线胀系数、不同温度与不同加载速率对粘结界面性能的影响；建立了全尺寸钢丝缠绕PSP有限元模型，通过内压-弯曲-温度联合作用下的失效分析验证了模型有效性，通过模型反演计算确定了混合界面失效准则，模拟再现了PSP接头区域管材内钢塑界面脱粘的全过程，PSP模型鼓胀变形趋势与实际相符。本项目相关成果可用于PSP复杂载荷下的失效模式分析、寿命预测以及其他类似的复合材料/结构承压设备的界面失效问题。