反应堆中随机振动作用下多模式耦合复杂微动损伤机理研究

在压水堆核电站中流致振动不可避免，燃料棒/格架、蒸汽发生器传热管/抗振条等关键构件在随机振动条件下的多模式耦合（切向+径向的双向复合微动磨损、微幅冲击磨损）复杂微动损伤，是重要的核安全隐患之一，但目前国内外相关研究较少，其机理尚未揭示。本项目拟以燃料棒配副为对象，首先基于随机振动的载荷谱和位移谱，对复杂微动损伤过程解耦，分别在恒幅和随机变幅工况下系统研究切向、径向微动及其复合的双向复合微动和冲击磨损的损伤行为及其动态演变规律；其次，研究在随机的切向位移和冲击载荷作用下的损伤行为及其相互作用机制；然后，耦合分析冲击和双向复合微动磨损对材料损伤的影响，揭示在非线性随机振动作用下的复杂微动损伤机理；最终，基于微动损伤过程耗散能与磨损量之间的定量关系，建立复杂微动损伤寿命预测模型。本研究不仅具有丰富微动摩擦学基础理论的科学价值，还具有为核电燃料棒组件的寿命评估和安全评价提供技术支撑的工程意义。

In pressurized water reactor, flow-induced vibration is inevitable. The contacting surfaces between key components, such as fuel rod/grid, steam generator tube/anti-vibration bar, and so on, are subjected to multi-mode coupling (tangential + radial dual composite fretting wear, impact fretting wear) complex fretting, which is one of the huge potential safety problems in nuclear industry. However, there were very few studies focused on the multi-mode coupling fretting wear in domestic and foreign, whose mechanisms are not revealed yet. The fuel rod is taken as the research objective in this project. Firstly, the complex fretting is decoupling based on the load and displacement spectrum induced by random vibration. The fretting wear behavior of tangential, radial and dual composite fretting wear as well as impact wear will be systematically conducted, and their interaction mechanisms also will be studied under constant and random amplitude. Secondly, the effect and interaction of random tangential displacement and impact load on the material damage will be investigated. Then, based on a coupling analysis method, the effect of impact and dual composite fretting wear on the material damage will be studied. Meanwhile, the complex fretting wear mechanism induced by nonlinear random vibration will be revealed. Finally, based on the quantitative relationship between dissipated energy and wear volume, a lifetime prediction model of complex fretting damage will be established. The project has a great important meaning not only in the science but also in the engineering, because it not only enriches basic theory of fretting tribology but also provides theoretical support for evaluation the security and service life of fuel assembly.