Effects of Non-Newtonian Couple Stresses on the Dynamic Characteristics of Wide Parabolic-shaped Slider Bearings

非牛頓偶應力效應對於拋物線剖面滑塊軸承動態性能之影響

林昭仁(Jaw-Ren Lin)

《中國機械工程學刊》 30卷1期 (2009/02) Pp. 67-74

https://doi.org/10.29979/JCSME.200902.0010

摘要

根據史托克氏之微連體理論，本文探討非牛頓偶應力效應對於拋物線剖面滑塊軸承動態性能之影響。為考慮牛頓流體潤滑劑在加入各種不同添加劑後所生之偶應力效應，本文利用史托克氏之偶應力流體運動方程式配合連續方程式推導得到一條可用以涵蓋非牛頓偶應力效應之動態雷諾型方程式。接著解出滑塊軸承動態壓力之解析解。若與使用傳統牛頓流體潤滑劑之情況比較，偶應力效應可以改善軸承之動態剛度與阻尼性能。當與平面剖面滑塊軸承使用非牛頓偶應力流體潤滑劑之情況 (Lin et al., 2003)比較，拋物線剖面滑塊軸承之設計可以得到更佳之剛度與阻尼性能。此種動態性能之改善，特別是在較低擠壓膜高度、較大幾何參數以及較大非牛頓偶應力參數之情況下更為顯著。本文結果之分析與探討，可提供工程師於軸承之選用與設計上有用之參考依據。

並列摘要

Based upon the micro-continuum theory developed by Stokes (1966), the present study investigates the non-Newtonian effects of couple stresses upon the dynamic characteristics of wide parabolic-shaped slider bearings. To account for the couple stress effects resulting from a Newtonian lubricant blended with various additives, the non- Newtonian dynamic Reynolds-type equation is derived using the Stokes motion equations together with the continuity equation. A closed-form solution for the bearing characteristics is obtained for engineering applications. Comparing with the parabolic-film Newtonian-lubricant case, the effects of couple stresses provide an increase in the dynamic stiffness and damping coefficients. Comparing with the inclinedplane bearings with couple stress fluids by Lin et al. (2003), the parabolic-film slider bearings signifies an improvement in the dynamic stiffness and dynamic characteristics; the improvement of bearing dynamics is more pronounced for lower squeezing-film heights and larger geometrical parameters and non-Newtonian couple stress parameters. The results of the present study provide engineers useful information in bearing selection and designing.

並列關鍵字

dynamic characteristics ； slider bearings ； parabolic-shaped film ； couple stresses ； microcontinuum theory