Dear friends, dear colleagues
«In the last decades, Tribology has moved, from the Tribology of Volumes, which attempted to produce friction and wear laws for different material combinations, through the Tribology of Surfaces, which rests strongly on surface science, to the Tribology of Interfaces which focusses on the role of the interface on friction and wear. ». With this background, Maurice Godet began one of his major publications, “Third-bodies in tribology”, in 1990.
The concept of the tribological triplet had been introduced at the beginning of the 1970s by Prof. Godet as an analytical tool for the interfaces of the contact. It takes into account the bodies of the contact and their relative displacement (first bodies), the mechanism containing the contact, and the volume of material that separates the first bodies while accommodating their difference in velocity (the third body).
Under complex loading, third body flows were foreseen in 1974 by Godet and J.J. Caubet. At the same time, they were experimentally observed by Yves Berthier at INSA de Lyon and by L.H. Sliney at NASA. Godet and Berthier then formalized this dynamic perspective of a contact through the concept of the tribological circuit, which describes the flow of material for an interface under friction.
However, the tribological circuit was not yet entirely sufficient to portray how first bodies and the third body carry load and accommodate the relative displacements in a contact. Thus, a second formalism - coupling sites (Si) and modes (Mj) of accommodation - was proposed by Dr. Berthier in 1988 to overcome this deficiency.
Thirty years after the introduction of these innovative concepts, they are still effective tools to analyze the interfaces of a contact. Initially used as descriptive means to formalize the observation of interfaces by tribologists, these ideas have increasingly become guides for the development of numerical and experimental tribological tools.
This seminar entitled “SiMj – 30 years existence” is forward-looking and seeks above all to further the exchange of ideas, experience and knowledge, by bringing together workers across many aspects of the tribology field.
