Post-impact squeeze-out behavior of oils with different pressure-dependent rheological properties

• Published in: Tribology international Vol. 187; p. 108695
• Main Authors: Fang, Jingbo, Wen, Xiangli, Bai, Pengpeng, Li, Xiaosong, Chen, Wenqing, Hou, Xin, Wen, Chengwei, Meng, Yonggang, Ma, Liran, Tian, Yu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2023
• Subjects: Dimple shape evolution; Film thickness; Pressure-dependent rheology; Squeeze-out behavior; Squeeze-out behavior; Pressure-dependent rheology; Film thickness; Dimple shape evolution
• ISSN: 0301-679X; 1879-2464
• DOI: 10.1016/j.triboint.2023.108695

The rapid approach of surfaces significantly increases pressure and viscosity of lubrication oil, trapping it in a dimple at the contact zone that requires time to be squeezed out. In this study, a measuring system was developed that utilized a ball-disk impact device and light interference technology to investigate the post-impact squeeze-out behavior of oils. Dimple shape evolution varied depending on the pressure-dependent rheological properties of the oils. Specifically, higher pressure–viscosity coefficients resulted in greater reduction in dimple radius, whereas lower pressure–viscosity coefficients led to quicker collapse in dimple height, providing a qualitative criterion for comparing pressure-dependent rheological properties of oils. Additionally, effect of initial dimple height and external load on the squeeze-out behavior were investigated. [Display omitted] •Collapse in dimple height and reduction in dimple radius are observed.•High pressure–viscosity coefficient of oil leads to significant radius reduction.•Dimples with varying initial heights converge to the same shape in a short period.•External load affects the pressure distribution and dimple shape evolution.