基于Nyquist稳定判据的磨合过程稳定性研究

在销-盘摩擦磨损试验机上进行了船用柴油机缸套-活塞环摩擦配副磨合磨损试验,采集磨合过程中摩擦振动信号,应用Nyquist稳定判据,通过摩擦振动Nyquist曲线对磨合系统稳定性进行分析.结果表明:摩擦振动Nyquist曲线反映了磨合系统稳定性变化.当摩擦副磨合开始时(0～10 min),摩擦振动Nyquist曲线不包围(-1,j0)点,磨合系统处于稳定磨损阶段;在摩擦副磨合进行过程中(10～40 min),摩擦振动Nyquist曲线包围(-1,j0),磨合系统处于不稳定磨损阶段;当摩擦副达到磨合时(40 min后),摩擦振动Nyquist曲线不包围(-1,j0),磨合系统处于稳定磨损阶段.因此,磨合系统的特性可揭示磨合过程稳定性变化规律.

Stability Characteristics of Running-in Process Based on Nyquist Stability Criterion

The running-in and wear tests of a piston ring against a cylinder available from marine diesel engine are conducted on a pin-on-disc tester. The friction vibration signals from the running-in process are collected. The nyquist stability criterion is used for analyzing the stability characteristics of the running-in system through the nyquist curve of the friction vibration. It is shown that the stability of the running-in system can be characterized by he nyquist curve of the friction vibration. When the friction pairs start running (0~10 min), the point (-1, j0) is not surrounded by the nyquist curve of the friction vibration, the running-in system runs under the stable wear state. When the friction pairs run during the running-in and wear process (10~40 min) , the point (-1, j0) is surrounded by the nyquist curve of the friction vibration, the running-in system runs under the unstable wear state. When the friction pairs achieve the running-in (after 40 min), the point (-1, j0) is not surrounded by the nyquist curve of the friction vibration, the running-in system runs under the stable wear state. Therefore the stability characteristics of running-in process can be revealed by the running-in system properties.