Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/1555
標題: 分子吸附力對破碎粗糙面與平面之彈 - 塑性接觸效應
Effect of Molecular Adhesion on the Elastic-Plastic Contact Between the Fractal Rough Surface and a Plane
作者: 何志成
關鍵字: Fractal rough surface;碎形粗糙面;contact;elastic-plastic deformation;surface adhesion;彈-塑性接觸;表面吸附力
出版社: 機械工程學系
摘要: 
摘 要
本文利用雙變數碎形函數來產生不同粗糙度的光滑面,配合赫茲接觸理論及JKR模型,進行有關於粗糙面與剛性平板受正向負荷之數值分析,以探討實際接觸面積、接觸負荷之關係,及接觸表面吸附力對接觸負荷的影響。
在進行數值分析的過程中,考慮了接觸尖點產生塑性變形時的體積守恆原則。選擇粗糙度很小的光滑面,以計算出在不同粗糙度下,接觸壓陷率、實際接觸面積比、實際接觸壓力等無因次參數之相互關係以及表面吸引力與接觸負荷比隨著不同的表面能、表面粗糙度等之變化關係。
數值分析的結果顯示:(1)在某一接觸壓陷率下,粗糙度愈大,表面接觸尖點中產生塑性變形的比率愈高。(2)實際接觸面積與接觸負荷間,存在一指數關係,即 ,且n值接近於一。(3)在某一接觸壓陷率下,表面粗糙度愈小,表面吸引力愈大;材料表面能愈大,表面吸引力愈大。(4)在某一外加負荷作用下,粗糙表面愈光滑,則接觸負荷愈大、實際接觸面積亦愈大;即粗糙表面愈光滑則表面吸引力效應愈明顯不可忽略。
關鍵字:碎形粗糙面、彈-塑性接觸、表面吸附力

Abstract
In the present paper , a rough surface against a flat plane are investigated. The smoothly rough surface is generated by the two-variable W-M function derived from fractal theory. The relationship of actual contact area versus the contact loading and the effect of molecular adhesion on the contact loading are analyzed numerically using Hertzian theory and JKR model.
The numerical analysis is performed by considering the volume conservation of plastically deformed asperities for the contact of a rough surface and a plane. The numerical analysis are performed to calculate the functional relationship of the real contact area and real contact pressure versus the approaching ratio and surface adhesion.
The results obtained from the numerical analysis are shown as follows: (1)For a given approaching ratio, the contact number of the plastically deformed asperities become larger when the rougher surface is encounted. (2)A power law relationship Ac~Lcn is proposed in this paper, and its exponent n approaches to unity. (3)For a given approaching ratio, the effect of surface adhesion is significant for a smooth surface having low surface roughness. (4)Under a given load applied on the plane, the contact load and the contact area are greater when the rough surface is smoother. In other words, the effect of surface adhesion should not be neglected for smooth and clean surfaces.
Keyword: fractal rough surface, elastic-plastic contact, surface adhesion
URI: http://hdl.handle.net/11455/1555
Appears in Collections:機械工程學系所

Show full item record
 
TAIR Related Article

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.