CFRP加固受损压力钢管线的界面裂纹扩展及剥离破坏机理研究

Steel pressure pipeline is a key component of the national energy transportation system, and its normal operation is of great significance for ensuring energy security. Environmental and human factors often cause damage to the pipeline. In order to repair damaged steel pipelines more efficiently and conveniently, engineers would like to use fiber-reinforced polymer (FRP) to strengthen damaged steel pipelines, rather than traditional cumbersome welding technology. However, the interfacial debonding failure mechanism of FRP-strengthened steel pipelines with penetrating crack remains poorly understood, which greatly limits the promotion and application of FRP reinforcement technology in the field of pipeline rehabilitation. In this study, carbon fiber-reinforced polymer (CFRP) is employed to retrofit the steel pipelines with penetrating crack, and the typical failure modes of interfacial debonding between CFRP and steel pipelines are investigated. A series of hydrostatic tests are conducted to characterize the interfacial failure in the adhesive between CFRP and steel pipeline, and the strain field of the CFRP-to-steel interface is measured by 3D digital image correlation method and infrared detection technique. Based on the experimental data, the cohesive zone models of CFRP-to-steel pipeline interfacial failure are constructed to explore the fracture propagation along the interface, and the mapping relationship between mechanical response and interfacial debonding. Finally, the mechanical theory and evaluation method of interfacial failure behavior are developed to reveal the interfacial failure mechanism of CFRP-to-steel pipeline. This study will provide solid theory foundation for CFRP-strengthened pipelines, which has crucial scientific significance and engineering guidance.

压力钢管线是国家能源运输系统的关键组成部分，保障其正常运行对确保国家能源安全具有重大意义。环境和人为因素常致使管道受损，为更高效便捷地修复受损钢管，工程师逐渐摒弃传统繁琐的焊接技术，改用FRP修复表面受损的钢管，但FRP加固含贯穿性裂纹钢管的界面破坏机理研究尚未成熟，这极大程度限制了该技术在压力钢管修复中推广与应用。为此，本项目拟使用CFRP加固含贯穿性裂纹钢管，分析其界面剥离这一典型的失效破坏模式；开展基于静水压实验的CFRP-钢管界面破坏行为表征，并利用3D数字图像相关技术和红外探伤技术实时监测裂纹扩展过程；建立CFRP-钢管界面破坏的内聚力模型，研究荷载响应与界面破坏过程的映射关系，探明界面破坏裂纹扩展规律；最终揭示CFRP-钢管界面剥离破坏机理，建立其界面破坏行为的理论体系和评估方法。该研究成果将为CFRP加固压力钢管提供有力的科学依据，具有重要的科学意义与工程指导价值。

油气管道是国家能源运输系统的关键组成部分，其正常运行对国家能源安全至关重要。环境和人为因素常导致管道产生贯穿性损伤，管道修复是延长其服役寿命的有效手段。除传统的焊接和机械连接技术外，安全便捷的纤维增强复合材料（FRP）修复管道新技术备受关注，但FRP加固含贯穿性裂纹钢管的界面破坏机理研究尚未成熟，这极大程度限制了该技术在压力钢管修复中推广与应用。为此，本项目拟使用碳纤维增强复合材料（CFRP）加固含贯穿性裂纹钢管，分析其界面剥离这一典型的失效破坏模式；开展基于静水压实验的CFRP-钢管界面破坏行为表征，并利用三维数字图像相关技术和分布式光纤传感技术实时监测裂纹扩展过程；建立CFRP-钢管界面破坏的内聚力模型，研究荷载响应与界面破坏过程的映射关系，探明界面破坏裂纹扩展规律；最终揭示CFRP-钢管界面剥离破坏机理，建立其界面破坏行为的理论体系和评估方法。该研究成果将为CFRP加固压力钢管提供有力的科学依据，具有重要的科学意义与工程指导价值。