ピッチングに至るき裂の進展に関する一考察 A Study on Propagation of Crack in Twin Disk Test
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Pitting is occurred from initiation of a surface crack under rolling-sliding contact. Lubricant has been said to have a crucial effect on pitting, however, few are known about contact condition, such as lubricant flow and pressure. In our twin disk tests, the contact electric resistance became conductive from insulated when the crack passed through contact region immediately before pitting. The contact electric resistance between two surfaces is influenced by insulating elastohydrodynamic lubrication (EHL) films. Thus, the reduction of the contact resistance is resulted from the breakdown of the EHL films due to local increase of the contact pressure. As a result of finite element method simulation of the contact pressure around the crack, the contact pressure at downstream edge of the crack was locally large. In the cross-sectional image of a crack immediately before pitting, we confirmed that the EHL films at the downstream edge of the crack collapsed with surface plastic deformation. When the crack passes through the contact region, the lubricant from upstream may be compressed into the crack due to local increase of the contact pressure.
- TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C 77(773), 187-195, 2011
The Japan Society of Mechanical Engineers