Recently, I published a new principle for equal elastic bodies in contact with friction, where the tangential problem is  reduced to the normal problem. Applications are impact problems, fretting, wear, existence and uniqueness problems, self-locking, and machine elements with friction. In the publications on this site, some examples of this principle are presented, using analytical and numerical methods for the solution. The papers are arranged chronologically on the left hand side.

 The elastic principle (Copyright © 1995, J. Jäger) states that the tangential traction between to equal bodies in contact is the difference of the full slip stress of the contact area and the stick area. Mathematically, it can be written in the following form

q = f (p-p*),  x = f k (z-z*) , Copyright© 1995, J. Jäger,

where q is the tangential traction, p the pressure, x the tangential displacement and z the normal displacement. Variables with asterisk * denote values of the stick area. Recently, the same results were published by other authors, and a critical comment can be found on this web site. The mathematical expression of the elastic friction principle was first published in Eq. (32) of the paper “Jäger, J., 1995, Axi-symmetric bodies of equal material in contact under torsion or shift, Arch. Appl. Mech., Vol. 65”. This publication concerns axisymmetric bodies, and it was explained at the GAMM conference 1996 that it holds in the same way for plane contact and multiple contact areas (Jäger, J., Ein neues Prinzip der Kontaktmechanik, Z. angew. Math. Mech., 1997, Vol. 77, S143-S144).  According to the Berne Copyright Convention (www.wipo.org), I am the legal copyright holder of this principle.  Copyright © 1995, J. Jäger.

 Below is my biography, as it appears in Marquis Who’s Who:

Who’s Who in the world, 18th edition, Marquis Who’s Who, New Providence, 2001, ISBN 0-8379-1125-7.

 Who’s Who in Science and Engineering, 6th edition, Marquis Who’s Who, New Providence, 2002.

Jäger, Jürgen,  research engineer; b. Laufenburg, Baden, Germany, Dec. 31, 1955; s. Klaus and Hildegard (Lapat) J. Diploma in engring., U. Karlsruhe, Germany, 1979; PhD, U. Delft, The Netherlands, 1992. Asst. U. Karlsruhe, 1980-85; engr. Industriewerke Karlsruhe Augsburg, Karlsruhe, 1986-90; ind.  rschr. Germany, 1990-98; rsch. engr. Ingenieurbüro für Anwendungen im Maschinenbau, Erlangen, Germany, 1998-99; design engr. Lauterbach Verfahrenstechnik, 1999-. Contbr. over 30 articles to  profl. publs., including Jour. Applied Mechanics, Engring. Fracture Mechanincs, others. Home: Blattwiesenstr. 7, 76227 Karlsruhe Germany. Office: Lauterbach Verfahrenstechnik, Postfach 711 117, 76338 Eggenstein, Germany.




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