粘弹性体润湿接触界面摩擦形成机制与调控

The contact interfaces of viscoelastic materials are widely existed in the important equipment seals, tire pavement systems, and have important influence on the service performance of the corresponding systems and equipments. The friction regulation also brings new requirement for the tribology theory. This project will coupling the factors of energy dissipation caused by deformation of viscoelastic material, hysteresis, liquid wettability, surface morphology, by studying influence of surface topography, the deformation of viscoelastic body on the movement mechanisms of contact line, formation and disappearance of Schallamach wave and its effect on contact characteristics, liquid bridge formation between interface and near the asperities on the interfacial adhesion and friction, the formation mechanism of friction of wetted interface is revealed, and the theory and method of friction control of wetted viscoelastic interface is established. Taking tread unit as an example, The friction between the interfaces is controlled by selecting the properties of the material and changing the surface morphology, The research results will develop and perfect the theory of tribological design of viscoelastic contact in essence. It is of great significance in improving the braking performance of the tire pavement system and improve its service safety significantly.

粘弹性体接触界面广泛存在于重大装备密封、轮胎-路面等系统中，对相应系统和装备的服役性能有重要影响，其摩擦调控对摩擦学理论也不断提出新的要求。本项目将耦合粘弹性体材料特性、变形引起的能量耗散及滞后效应、液体的润湿性、表面形貌等因素的影响，通过研究表面形貌、粘弹性体变形等对接触界面润湿接触线移动机制的影响、界面间分离波的形成与消失对接触特性的影响、界面及微凸体附近液桥的形成、演变及其对界面粘着和摩擦的影响，揭示润湿状态下粘弹性体接触界面摩擦的形成机制，建立粘弹性体润湿界面摩擦调控的理论与方法。结合轮胎-路面单元，通过选择材料特性和改变表面形貌等参数实现界面间摩擦的调控；研究结果将从本质上发展和完善粘弹性体摩擦学设计理论，为改善湿滑条件下轮胎-路面制动性能并提高其服役安全性具有重要的意义。

针对粘弹性体接触界面润湿转变中的摩擦峰机理与调控问题，本项目从接触界面间残余水膜的分布和力学特性入手，首先搭建了一种可进行原位观测的超高精度摩擦磨损试验机，探究了静态和动态氮化硅（Si3N4）球与聚二甲基硅氧烷（PDMS）接触界面润湿转变过程中法向载荷及摩擦系数的演变规律，分析了接触界面间残余液体对粘弹性体接触行为和摩擦特性的影响机制；然后分析了摩擦系数、接触形态、水膜面积占比等参数的演变规律，量化了水膜的厚度分布和橡胶表面的变形情况，明晰了纳米级离散分布液桥、橡胶的粘滑特性与粘着态下的瞬态高摩擦系数之间的相关性；并通过研究表面粗糙度对低弹性模量和玻璃表面接触界面粘着态下宏观摩擦系数的影响，首次实现宏观尺度多微凸体接触中界面粘附力的直接测量，为介观毛细管桥诱导界面粘附力增大提供了直接的实验证据。此外，进一步探究了粘弹性体的材料属性、表面粗糙度、表面润湿性及工况条件对摩擦峰的调控机制，定性地指出各影响因素对粘着态摩擦峰的影响机理，为实现对粘着态摩擦峰的调控提供理论指导。最后，基于利用自主研制的线性往复摩擦磨损试验机和粘弹性体摩擦试验机分别对粘弹性润湿接触界面以及真实轮胎-路面的摩擦与抗湿滑特性进行了实验研究。