ENME Webcast Fall 2006
Leaders in Mechanical Engineering Lecture Series
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Title: The Evolution of Contact Mechanics
Professor Leon M. Keer
Northwestern University,
Department of Mechanical Engineering
Original Air Date: Friday, October 13th at 3:00pm
Abstract: The theory of Hertz was developed in 1882 to solve the specific problem of frictionless, elliptical contact between two bodies. The Hertz assumptions allowed a solution to be realized in closed form for both the contact stresses and interior stress field. The theory became so popular that contacts not satisfying these assumptions were called non-Hertzian. Real surfaces, however, consist of many asperities. For two rough surfaces their area of contact is usually smaller than that predicted by Hertz because of the asperity contacts. Due to the needs of industry and the development of high-speed computers, recent research in contact mechanics has been focused on surfaces with real, engineered roughness, surfaces with hard protective coatings, misalignment and other types of contacts not in the category of Hertzian. In addition the inelastic behavior of contacts can also be an issue. This talk will review some of the analytical and computational techniques used to develop realistic and computationally efficient tools for solving such problems. The focus will be on four general areas of contact as follows: Hertzian contact and analytical solutions; Non-Hertzian Contact Issues of Geometry; Frictional Contact; and Problems Requiring Computational Methods. The description of how the mathematical framework has evolved from developing solutions in an analytical form to ones that are solved from a purely computational approach. These latter approaches are made necessary by the industrial focus on surface phenomena, which requires retention of component life with increasing load requirements. The extension to ever-smaller length scales will be mentioned briefly.
