Regarding the Question of Calculation of Contact Pressure in Metal-Polymer Plain Bearings during Wear

A method for calculating hybrid (metal-polymer) plain bearings for contact strength (bearing capacity) is presented. The method takes into account a significant difference in the mechanical properties of the shaft and bushing materials, in particular, Young's moduli (by a factor of 40–100). Numerical studies of metal-polymer bearings with a bushing made of two types of PA6 polyamide based composites filled with glass (30% GF) or carbon (30% CF) dispersed fibers are carried out. It is found that, for the accepted calculation data, the maximum contact pressures increase in proportion to the square root of the increase in the external load on the bearing, regardless of the radial clearance and bushing material; an increase in contact pressures is proportional to an increase in the radial clearance in the joint; in a carbon composite bushing with higher Young's modulus ЕCF, the pressures will be $$\sqrt {{{{{E}_{{{\text{CF}}}}}} \mathord{\left/ {\vphantom {{{{E}_{{{\text{CF}}}}}} {{{E}_{{{\text{GF}}}}}}}} \right. \kern-0em} {{{E}_{{{\text{GF}}}}}}}} $$ times higher on average than in a glass composite bushing with modulus ЕGF. The results of the numerical solution by the developed method of contact mechanics are compared with the results of the solution according to the simplest technique used in engineering practice for calculating the contact pressures in plain bearings according to the criterion of average pressure, and it is shown that this simplest technique is unreasonable, because there is a significant difference (4.0–9.7 times) between the average contact pressures and the maximum pressures. The practical significance of the developed method lies in the fact that with its use it is possible to calculate the contact and wear contact pressures in the design calculation of the metal-polymer plain bearings in contrast to the methods known in the literature for solving this wear-contact problem.