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	弾性流体潤滑	グリフィス破壊力学
分野	製造工学	製造工学
系統	Process / pipeline	Process / pipeline
提唱年	1977	1921
提唱者	Dowson, D., Higginson, G. R.	Alan A. Griffith
種類	Mathematical model for lubricated contacts	Theoretical model for brittle fracture and crack propagation
原典	Dowson, D., & Higginson, G. R. (1977). Elastohydrodynamic Lubrication: The Fundamentals of Roller and Gear Lubrication. Pergamon Press. ISBN: 0-08-021710-4	Griffith, A. A. (1921). The phenomena of rupture and flow in solids. Philosophical Transactions of the Royal Society A, 221, 163-198.
別名	EHL, Elastohydrodynamic film, Hydrodynamic lubrication	Brittle fracture theory, Energy release rate, Linear elastic fracture mechanics
関連	4	4
概要	Elastohydrodynamic lubrication (EHL) is the regime of fluid film lubrication in which elastic deformation of the surfaces plays a crucial role in maintaining a fluid layer between sliding or rolling surfaces. In applications like roller bearings and gears, the contact pressure is extremely high, causing the lubricant viscosity to increase dramatically and the surfaces to deform elastically. EHL theory, developed rigorously by Dowson and Higginson, predicts the film thickness, pressure distribution, and friction in these heavily loaded contacts.	Griffith's theory of brittle fracture explains how small flaws or cracks in materials grow unstably, leading to sudden catastrophic failure. Formulated by Alan A. Griffith in 1921 through experiments on glass fibers, this theory balances the elastic energy released by crack growth against the surface energy required to create new material surfaces. It predicts that materials fail at stresses far below their theoretical strength due to the stress concentration around pre-existing flaws.