Novel design of pin-on-disc sliding mechanism for tribotesting of thin film metallic glass coating on carbon fiber reinforced composites

• Main Authors: Jing-Guo Yang, 楊靖國
• Other Authors: Chun-Liang Kuo
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/3zh5s8

碩士 === 國立臺灣科技大學 === 機械工程系 === 107 === This work presents a novel design of a Pin-on-Disc tribotesting system with retrofit applications in CNC machining centres to exhibit synchronised measurements of forces, temperatures, electrical signals. Based on the recorded measurements of coefficient of friction, electrical current and sliding temperature in a full factorial (4×3×3) experiment, normal load (10–30 N), sliding speed (50–100 m/min) and coated thin film metallic glass (TFMG: 0.25–2 μm) in the sliding pair with carbon fibre reinforced plastic (CFRP), residuals of the observations can be resolved and identified. With statistical analysis in the stochastic condition, parametric outliers interacting with system can be determined, as well as the model values and the associate the confident intervals to be identified. In the conditions of insulating or removing the outliers, the established Pin-on-Disc tribotesting system delivered with an appreciable precision level (R2 >85%) over 36 validation tests. Following the accuracy of the Pin-on-Disc tribotesting system being validated, influences of the operating parameters on the coefficient of friction, electrical current and sliding temperature would be consequently investigated. In the fit analytical models for the contact forces and grinding ratio, tribology effects of the TFMG coating were considered and initiated. When comparing the experimental results against the validated model values, a good agreement of the model accuracy (89.02%) to the experimental results was presented. In the evolution tests, the main effects and variances of the operating parameters on the observations were exanimated and discussed. Moreover, the preferable low coefficient of friction and sliding temperature could be obtained, with the significant factor of the coated thickness in PCR of 43.2% and 25.9% respectively. However, when the coating on the pins were worn and removed in the test interval Ⅳ (30–40 sec), the significant factor to the coefficient of friction and sliding temperature was diverted to sliding speed with PCR of ~52.0% and ~71.9% respectively. In the SEM observations of the microstructures on the worn TFMG coated pins and the CFRP discs, characterisations of the wear patterns and behaviour were reported and detailed with micrographs.