中文摘要：

模态耦合是摩擦系统振动不稳定性的重要机理之一，它会受到系统摩擦副的结构阻抗特性和摩擦接触特性的显著影响。针对一类由一个摩擦副部件的不同方向模态导致耦合不稳定性的现象，建立2自由度摩擦振动动力学模型，推导在摩擦副部件机械阻抗特性相差极大的条件下，系统摩擦耦合模态不稳定性及其对摩擦力方向的依赖性，以及研究了不稳定区域对摩擦副结构和摩擦接触特性参数的敏感性；同时，也分析摩擦副部件的自身约束模态频率和系统接触模态频率对系统摩擦耦合模态区域和频率的影响。这为指导以避免模态耦合的摩擦振动系统的结构参数和摩擦接触参数匹配，以及识别摩擦振动不稳定的摩擦副模态来源提供了理论依据。

英文摘要：

Mode coupling is one of the important mechanisms of instability of friction vibration system, which will be significantly affected by structure impedance characteristic and the contact characteristic of the system friction pairs. A 2-DOF vibrational dynamic model is established for the phenomenon that the different directional modes of a friction pair lead to instability to deduce mode coupling instability and its dependence on the direction of friction force when friction pair components vary greatly in mechanical impedance properties and to study the sensitivity of the unstable areas to the friction pair structure and friction contact parameters. At the same time, the relationship among the constraint mode, the contact mode and the coupling mode of the friction components is analyzed as a guide to match the structure parameters and the friction contact parameters of the vibration system to avoid mode coupling as well as a theoretical basis to identify the source of friction pair mode resulting in the instability of the friction-induced vibration.