EHL of an Elastic Ball Impact and Rebound from a Lubricated Elastic Coated Surface

具彈性鍍層表面受彈性球衝擊及反彈之彈液動潤滑研究

朱力民(Li-Ming Chu) ； 張簡才萬(Chang-Jian, Cai-Wan) ； 張育斌(Yuh-Ping Chang)

《中國機械工程學刊》 39卷2期 (2018/04) Pp. 215-222

摘要

The pure squeeze elastohydrodynamic lubrication (EHL) motion of circular contacts with an elastic coating is investigated at impact and rebound process from a lubricated surface. The Reynolds, the ball motion, the rheology, and the elastic deformation equations must be solved simultaneously to obtain the transient pressure profiles (P), film shapes (H), elastic deformation, normal squeeze velocities (V_c) and accelerations (A_c). The first peak of central pressure (P_c) occurred at maximum impact force at impact end. In the rebound process, cavitation appears at the position near the edges of the dimple, the pressure spike (P_s) and the minimum film thickness (H_min) are developed at the edges of the dimple because of mass conservation, and closing moves towards the center of contact. At the end of rebound the Ps reached the contact center. The secondary peak is greater than the first peak. The effects of the elastic modulus (E) and thickness of coating (d) at impact and rebound process from a lubricated surface are discussed. Moreover, this research possesses academic innovation and value of industrial application, so it can be utilized by the industry to design and analyze mechanical components with coating.

關鍵字

EHL ； Elastic coating ； Elastic ball ； Impact ； Rebound

並列摘要

本研究探討牛頓潤滑劑在具鍍層接觸表面受衝擊及反彈之彈液動潤滑問題。將暫態雷諾方程式、運動方程式、流變方程式及彈性變形方程式耦合起來，求解此一非線性微分方程組，可解得暫態的壓力分佈、油膜分分佈、彈性變形、擠壓速度與擠壓加速度。結果顯示，中心壓力隨時間變化的第一峯值發生在衝擊結束即產生最大衝擊力時，在反彈過程中，由於質量必須守恆，所以空蝕現象會發生在內凹邊緣處附近，而壓力尖突及最小油膜都會發生在內凹邊緣處，且會隨著時間增加而向中心接近，當壓力尖突到達接觸中心處時，反彈結束，此壓力尖突也為中心壓力的第二峯值，第二峯值大於第一峯值。本研究也討論鍍層的彈性模數及厚度對衝擊及反彈過程彈液動潤滑的影響。本研究具有學術創新性，並可供工業界設計分析具鍍層的機械元件時使用，具產業應用價值。