LI Guobin^1*, HUANG Yehua², WEI Haijun^1,3

(1.Marine Engineering College, Dalian Maritime University, Dalian 116026, China; 2.China National Offshore Oil Corporation Cnooc jz25-1s Oil and Gas Field Development Pmt, Tanggu 300452; 3.Mechant Marine College, Shanghai Maritime University, Shanghai, China, 200135 )

Abstract: 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.

Key words: nyquist stability criterion; friction vibration; running-in system; stability

E-mail: guobinli88@yahoo.com.cn 

Tribology, Vol. 32, Issue 4, 2012, 325~331