Electromechanical Dynamics (Part 1).0063

Electromechanical Dynamics (Part 1).0063 - f, which must be...

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Lumped Electromechanical Elements Refer displi Fig. 2.2.8 Coulomb friction between members in contact. is lengthy and complex*; most practical devices, however, can be modeled as described or by one of two nonlinear models that we now discuss. The first of these additional models is coulomb friction which is character- istic of sliding contacts between dry materials. See Fig. 2.2.8 in which the blocks are assumed to have negligible mass. If we apply constant, equal and opposite, normal forces f,, as shown, and then apply equal and opposite forces f, as shown, the blocks may or may not move relatively, depending on the friction coefficient of the surface. If we vary the force
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Unformatted text preview: f, which must be balanced by the friction force f, for steady motion, and measure the resultant steady relative velocity, we can plot the friction coefficient (f,/f,) as a function of relative velocity (see Fig. 2.2.9). The quantity z, is the coeffi-cient of static friction and ,p is the coefficient of sliding friction. When we Friction coefficient= -fn-Ms 10 d(X2 -1) = relative velocity dt Fig. 2.2.9 Typical coulomb friction characteristic. * See, for example, G. W. Van Stanten, Introduction to a Study of Mechanical Vibration, 3rd ed., Macmillan, New York, 1961, Chapter 14. A-PDF Split DEMO : Purchase from www.A-PDF.com to remove the watermark...
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This note was uploaded on 02/10/2012 for the course MECE 4371 taught by Professor Liu during the Fall '11 term at University of Houston.

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