Machine-vision-based assessment of frictional vibration in water-lubricated rubber stern bearings

Frictional vibration is a common but not entirely understood tribological phenomenon in water-lubricated rubber stern bearings. This paper proposes a transparent glass cylinder and rubber block model which reveals the frictional contact area under a high-speed camera. The local displacements of different grid points on the contact area can be measured by machine vision. A conjoint analysis method for friction coefficient, vibration, noise, and image information is used to determine the mechanisms of frictional vibration. The frequency of noise accompanying the vibrations can be exploited to divide frictional vibration phenomena in the bearing into squeal and chatter categories, each with different vibration modes. The frictional force and image information can be compared to determine the causes of frictional vibrations in different frequency bands. And a physical model which reflects frictional vibration effects on the stern tube bearing is created by images captured by high speed camera. The results presented here may provide a theoretical foundation for the manufacturing and optimization of water-lubricated rubber stern bearings.