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Improved understanding of fretting induced friction helps design more reliable machines

Machine breakage is often due to dynamic loading caused by damage in machine element interfaces. Better understanding of fretting contacts helps design more advanced machines with improved durability.

In order to succeed in global markets, the mechanical engineering industry must constantly improve its products. The pursuit of increased power density, improved efficiency and fuel economy leads to conditions in which the strength of engineering materials needs to be utilized to a high degree without excessive safety margins. The machine element interfaces play a crucial role in this, as they are subject to the highest uncertainties. In his dissertation, MSc Jouko Hintikka studied friction mechanisms and damage in fretted surfaces.

“Fatigue failures in machine elements may occur suddenly and result in catastrophic outcomes. Fretting fatigue is especially challenging for machine designers due to an insufficient understanding of friction and surface damage mechanisms under fretting conditions,” Hintikka explains.

Hintikka used experimental methods for studying friction, fretting fatigue and fretting wear, focusing mostly on characterizing friction and examining friction mechanisms.

“Friction between machine elements is typically described with one parameter: the friction coefficient. Recent research results show that one parameter is inadequate for describing fretting induced friction with precision, however. Fretting wear leads to local wear damage and very high local friction values, which may ultimately lead to fatigue failures,” Hintikka describes.

Better knowledge of fretting induced friction and damage mechanisms enables the development of novel, advanced design criteria, which are, in fact, currently being developed.

Public defence of a doctoral dissertation on Monday, 27 June 2016

MSc Jouko Hintikka’s doctoral dissertation ‘Fretting Induced Friction, Wear and Fatigue in Quenched and Tempered Steel’ will be publicly examined at the Faculty of Engineering Sciences of Tampere University of Technology (TUT) in Auditorium K1702 in the Konetalo building (address: Korkeakoulunkatu 1, Tampere, Finland) at 12 noon on Monday, 27 June 2016.

The opponents will be Professor David Nowell from the University of Oxford, UK and Professor Braham Prakash from Luleå University of Technology, Sweden. Professor Arto Lehtovaara from the Department of Materials Science of TUT will act as the Chairman.

Jouko Hintikka works as a researcher in the Tribology and Machine Elements research group at the Department of Materials Science of TUT.

Further information: Jouko Hintikka, +358 (0) 408490576, jouko.hintikka@tut.fi

The dissertation is available online at  http://urn.fi/URN:ISBN:978-952-15-3780-6

News submitted by: Tiina Leivo
Keywords: science and research, fretting induced friction