Friction in Machine Design

This paper reviews available friction model information and the practical equations that apply to determination of friction force. These models are critiqued and recommendations are made on how to treat friction data inquiries. Guidelines are presented on use of available models, friction testing, and friction databases for metal and non-metal couples. Friction models are currently inadequate in their ability to supply “hard numbers,” for real sliding systems; for the present the designer must rely on estimates or testing.