الفهرس 
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Abstract
This work implies two parts, the 1st deals with the effect of surface roughness and the centripetal inertia on the hydrostatic thrust spherical bearings. On the basis of the stochastic theory, Reynolds equation is developed. Expressions for the pressure distribution, load carrying capacity, volume flow rate, frictional torque, friction factor, power factor, power losses and stiffness factor are obtained. This part shows the combined effects of the centripetal inertia and the surface roughness on the bearing performance. An optimum design based on the minimum power losses, minimum flow rate and optimal restrictor dimensions is theoretically designed. The 2nd part has theoretically analyzed the surface roughness, centripetal inertia and recess volume fluid compressibility effects on the dynamic behavior of a restrictor compensated hydrostatic thrust spherical ’ fitted and clearance’ type of bearings. The stochastic Reynolds equation, with centripetal inertia effect, and the recess flow continuity equation with recess volume fluid compressibility effect have been derived to take into account the presence of roughness on the bearing surfaces. On the basis of a small perturbations method, the dynamic stiffness and damping coefficients have been evaluated. In addition to the usual bearing design parameters; the results for the dynamic stiffness and damping coefficients have been calculated for various frequencies of vibrations or squeeze parameter and recess volume fluid compressibility parameter. The study shows that both of the surface roughness and the centripetal inertia have unimportant effects on the dynamic stiffness coefficient and noticeable effects on the damping coefficient while the recess volume fluid compressibility parameter has the major effect on the bearing dynamic characteristics. The orifice restrictor showed better dynamic performance than that of the capillary tube. The dynamic stiffness and damping coefficients are presented for capillary tube and/or orifice compensated bearing.