结构系统接触界面滑动-冲击耦合损伤机理及寿命表征研究

The thermal-solid-liquid complex operational environment induces structure systems developing the typical coupling sliding-impact behavior. It results in contact interface damage until system fails. In addition, external uncertainty factors bring other difficulties to make that effective design and assessment can not be carried of structure system reliability and life. Sometimes it can even cause significant economic losses and catastrophic consequences. The key point to solve this problem is to reveal the coupling damage mechanism of sliding-impact behavior which happens on the typical structure systems and their change law of life cycle in complicate evolving environment with uncertainties. This has been a hot research topic in the field of mechanical reliability. The main work in this project included these following sections. Firstly, a time-varying contact model was established based on the hybrid fractal theory and time-series method. The geometrical and time variation characteristics of the worn surfaces could be revealed. Then, Multi temporal dimension coupling effect could be distinguished between the sliding motion and impact process. The coupling wear equation constructed was the reference to the form of the sliding wear equation which belongs to coexisting of more wear mechanisms. Finally, combining the mechanical response and functional characteristics, our wear life model was provided to describe change law of life cycle under uncertainties of load and threshold. The significance was noticeable to reveal quantitative relationship between coupling wear equation and life characteristic. Moreover, it could describe the influence of uncertain factors on the variation of wear life. Generally, this project deepens the mechanical reliability technology based on damage mechanisms. And it also has academic and practical meaning for improving reliability design ability, life prediction and maintenance supportability of structure systems.

结构系统在热-固-液多种载荷综合作用下，滑动、冲击行为同时出现，造成接触界面产生耦合损伤，再由于载荷的不确定性影响，使可靠性设计与寿命预测更为复杂和困难，是导致系统出现灾难后果的主要因素之一。有关耦合损伤机理的揭示以及不确定性因素对系统寿命变化规律的研究是解决该问题的关键，也是当前机械可靠性领域研究的热点。基于复合分形理论和时间序列建立复杂环境载荷作用下的界面接触模型，揭示了磨损表面的几何特征和时变特征；阐明滑动和冲击两种运动形式在时空多维度的耦合机制，建立了多机理并存的耦合磨损方程；结合系统力学行为和功能特征，构建了考虑载荷和磨损阈值双重不确定性影响的磨损寿命表征模型，不仅揭示了耦合磨损方程与寿命表征之间的定量关系，而且定量化描述了不确定因素对磨损寿命变化规律的影响。深化了基于故障物理的可靠性技术，对于提高不确定环境条件下的结构系统可靠性设计与寿命预测能力具有重要的理论和现实意义。

结构接触界面在复杂载荷作用下，滑动、冲击等不同运动形式同时出现，诱发界面耦合损伤行为进而引发异常磨损。现有研究未能反映由滑动导致的粘着、磨粒等典型机理之间、以及与冲击导致的疲劳等典型机理之间存在的耦合过程，使得结构系统的可靠性设计与耦合磨损寿命预测成为该研究领域的瓶颈问题。为了解决这一关键问题，本项目主要针对结构系统接触界面滑动-冲击耦合损伤机理及寿命表征开展了深入研究，并取得了许多重要研究成果。第一，考虑了复杂环境载荷对界面接触行为的影响，基于变性能理论及加卸载准则构建了随机冲击作用下界面时变接触模型；第二，基于界面接触模型，开展滑动行为下粘着、磨粒等特征机理间的耦合机制，建立了多机理并存的滑动耦合磨损方程；第三，基于分形接触模型及磨损理论，进行滑动-冲击磨损损伤机理特征分析，并构建了黏着-疲劳、磨粒-疲劳两类耦合磨损方程；第四，基于仿真手段及系统建模方法，确立了磨损程度与结构参数关系的表征模型，结合系统力学响应及功能特征，提出了考虑不确定性的耦合磨损寿命表征方法。以上成果充分考虑了复杂环境载荷的不确定性导致的系统滑动-冲击耦合磨损行为，基本解决了界面时变接触模型构建及滑动-冲击耦合行为损伤演化及寿命表征两个核心问题，初步建立了结构系统接触界面滑动-冲击耦合磨损寿命建模理论框架，为机械产品结构接触界面实况载荷下的磨损行为研究提供了一条全新的、有效的、更合理的途径，具有广阔的理论价值和应用前景并已在柴油机电控喷油嘴、附件机匣齿轮传动系统及船用低速机增压项目中取得了不错的效果。在本项目的资助下，项目组在Mechanical Systems and Signal Processing、Wear、Tribology Transactions、Reliability Engineering and System Safety 等多个国际顶尖学术期刊发表学术论文13篇，被引次数达101次。项目组成员积极参与国内外学术交流，参与了WCCM、ICTIS、MMR等顶级国际会议，以本项目成果为主题进行了2次大会报告，与加拿大阿尔伯塔大学左明建教授、英国肯特大学Wu Shaomin教授等著名专家团队学者建立了合作关系。