Vibration-based detection of spalling initiation in polymer composites using a custom ball-on-disc tribometer
摘要
We report a custom-designed ball-on-disc tribometer that enables quantitative detection of the onset of surface damage in polymer composites under continuous sliding contact. Conventional tribometers primarily monitor friction coefficients; however, they often fail to detect the precise initiation of surface damage. In contrast, the system developed in this study continuously monitors vibration signals during sliding and identifies the initiation of surface damage—such as crack formation and material detachment—as a sudden and pronounced increase in the vibration signal. Optical microscopy confirms that this abrupt increase in vibration coincides with the onset of spalling and surface cracking. Using this approach, we quantitatively evaluated the effects of the glass-fiber (GF) content and surface roughness on the damage onset time in GF-reinforced polyamide 66 composites. The proposed methodology provides a sensitive and robust tool for characterizing early-stage spalling in polymer composites under continuous sliding contact.