摩擦力和摩擦振动的分形行为研究

在不同的摩擦磨损试验机上提取了摩擦磨损过程中摩擦力和摩擦振动的时间序列信号,采用关联维数方法研究了摩擦力和摩擦振动的分形行为．结果表明：摩擦力和摩擦振动信号具有分形特征;随着摩擦磨损过程的进行,信号分形维数的变化出现规律性的递增或递减;对于“收敛”或磨合磨损过程,不同阶段摩擦信号的分形维数趋于增大;对于“发散”的摩擦磨损过程,不同阶段的摩擦信号的关联维数趋于减小．摩擦力和摩擦振动的分形维数的变化规律同摩擦磨损过程中表面形貌分形维数的变化规律相似。

Study on the Fractal Behaviors of Frictional Forces and Vibrations

The friction and wear tests of a Cu-Zn alloy/SAE52100 steel pair and a quenched SAE52100 steel/tempered 5210 steel pair were conducted on a pin-on-disc test rig and an end-surface friction and wear tester under dry sliding and oil-lubricated sliding, respectively. The sequence signals of the frictional forces and vibrations were collected. The fractal behaviors of the frictional force and vibration signals were studied making use of correlation dimension. The results showed that the sequence signals of the frictional forces and vibrations had fractal characteristics, and the fractal dimensions of the signals varied with the test duration. The correlation dimension increased gradually for the "converging" (or running-in) friction and wear process, while it decreased gradually for the "diverging" friction and wear process. Moreover, the fractal dimensions of the frictional forces and vibrations varied in the same changing law as that of the worn surface morphology.