UNLUBRICATED METAL ON METAL SLIDING CONTACT AND ITS ACOUSTIC EMISSION SIGNATURES
Wear mechanisms are conventionally identified by examination of worn surfaces using optical or electron microscopy. This is effective but time consuming and destructive under most circumstances. This study aims to establish acoustic emission (AE) signatures to enable identification of wear mechanisms and contact health for dry metal on metal sliding contacts in real time. Experiments were designed based on the Lim-Ashby wear map to generate tests dominated by different single wear mechanisms enabling signature mapping. Steel on steel dry sliding tests were carried out at room temperature on a ball-on-disc tribometer at 0.2 m/s sliding speed and 1.1 GPa initial contact pressure. Tests were stopped when interesting friction features occurred to enable mechanistic/chemical identification of the surface features to examine the contact physics. Surface examination showed, for the three-hour test, two distinct wear regions were identified as dominated by plastic deformation and mild delamination disc wear. The average coefficient of friction (COF) in the two regions was 1.2 and 0.9 respectively. The integrated AE RMS (root mean squared) was found to be proportional to the ball wear volume but to the two different exponent in the two regions due to the change in wear mechanisms. This change of the exponent is effectively an indication of the change of the wear mechanism. Other AE parameters include AE energy and amplitude distribution which are also corroborated by mechanistic changes. Detailed investigations of the wear processes indicated that within the delamination region, cyclic processes alternating between ratchetting and abrasion on the ball generated periodic COF peaks that are correlated to periodic AE rms signals. This study has shown that AE signals have good correlations with both average COF and instantaneous friction changes in that they are related to wear mechanisms.
condition monitoring dry sliding contact acoustic emission
Ling Wang Robert Wood Jun Sun
The national Centre for Advanced Tribology at Southampton (nCATS), School of Engineering Sciences, U Albright Electro-Mechanical (Shanghai) Ltd., Building 18, Sheshan Metropolitan Industrial Park, Shen
国际会议
北京
英文
1614-1624
2008-10-27（万方平台首次上网日期，不代表论文的发表时间）