O’zbekistоn respublikasi оliy va o’rta maxsus ta`lim vazirligi
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анг Трибология. Махкамов
For run-in surfaces, the coefficient of friction is independent of the load and can be calculated from the equation: (5.9) where E is the modulus of elasticity of the deformable body. It is interesting to note that, according to Yu.N. Vasiliev, the coefficient β characterizes the share of the work of the friction forces spent on the wear of rubbing bodies. Thus, the total coefficient of friction on a single contact patch (5.10) where for plastic contact k=0.55; for elastic k=0.2α g . Calculation of friction coefficient for multiple contact. For an ensemble of irregularities, the friction forces on single contact patches are summed up and, for a multiple contact, the friction forces are calculated by the formula: (5.11) where ΔF i - friction force arising on a single arbitrary microroughness; n g is the number of microroughnesses that have penetrated to the same depth. After a series of substitutions and simple transformations, equations for calculating the friction coefficient for various types of frictional contact are obtained from here. Such an equation looks like: for unsaturated elastic contact (5.12) for saturated elastic contact (5.13) (5.14) for saturated plastic contact (5.15) In the above calculation equations: τ 0 and β - friction constants, depending on the physico-chemical state of the surfaces of the contacting bodies; α g - coefficient of hysteresis losses; ν - parameter of the reference curve of the surface profile; k 1 - coefficient depending on the parameter ν (Fig. 6); E - modulus of elasticity of the deformable body; µ - Poisson's ratio; h - the value of the convergence of surfaces (depth of introduction of a single unevenness); r is the radius of the irregularity modeled by the sphere; h cf - the average value of the introduction. The analysis of the above equations shows that they take into account the physical and mechanical properties of the contacting bodies: in equations (5.12) and (5.13) - through the quantities E, µ, α g ; in equations (5.14) and (5.15) - through the quantities HB; physical and chemical properties of interacting surfaces through the values of the parameters τ 0 and β, microtopography of surfaces through the values of ν and r, loading parameters - through the values of h - in all equations. Download 1.64 Mb. Do'stlaringiz bilan baham: 
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