Elastoplastic contact mechanics model of rough surface based on fractal theory

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• 作者：Yuan Yuan ; Li Gan ; Kai Liu ; Xiaohui Yang
• 关键词：rough surfaces ; asperities ; fractal theory ; contact model
• 刊名：Chinese Journal of Mechanical Engineering
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：30
• 期：1
• 页码：207-215
• 全文大小：
• 刊物主题：Mechanical Engineering; Theoretical and Applied Mechanics; Manufacturing, Machines, Tools; Engineering Thermodynamics, Heat and Mass Transfer; Power Electronics, Electrical Machines and Networks; Elec
• 出版者：Chinese Mechanical Engineering Society
• ISSN：2192-8258
• 卷排序：30

文摘

Because the result of the MB fractal model contradicts with the classical contact mechanics, a revised elastoplastic contact model of a single asperity is developed based on fractal theory. The critical areas of a single asperity are scale dependent, with an increase in the contact load and contact area, a transition from elastic, elastoplastic to full plastic deformation takes place in this order. In considering the size distribution function, analytic expression between the total contact load and the real contact area on the contact surface is obtained. The elastic, elastoplastic and full plastic contact load are obtained by the critical elastic contact area of the biggest asperity and maximun contact area of a single asperity. The results show that a rough surface is firstly in elastic deformation. As the load increases, elastoplastic or full plastic deformation takes place. For constant characteristic length scale G, the slope of load-area relation is proportional to fractal dimension D. For constant fractal dimension D, the slope of load-area relation is inversely proportional to G. For constant D and G, the slope of load-area relation is inversely proportional to property of the material ϕ, namely with the same load, the material of rough surface is softer, and the total contact area is larger. The contact mechanics model provides a foundation for study of the friction, wear and seal performance of rough surfaces.