ANALYSIS OF BELT-DRIVE MECHANICS USING A CREEP-RATE DEPENDENT FRICTION LAW

摘要

An analysis of the frictional mechanics of a steadily rotating belt-drive is carried out using a physically-appropriate creep-rate dependent friction law. Unlike in belt-drive mechanics analyzed using a Coulomb friction law, the current analysis predicts no adhesion zones in the belt-pulley contact region, although all response quantities (including the belt creep) approach those of the Coulomb law for a steep enough creep-rate law. Depending on the slope of the profile, one or two sliding zones exist on each pulley, which together, span the belt-pulley contact region. Closed-form expressions are obtained for the tension distribution, the sliding-zone arc magnitudes, and the frictional and normal forces exerted on the belt. A sample two-pulley belt-drive is analyzed further to determine its pulley angular velocity ratio and belt-span tensions. Results from this analysis are compared to a dynamic finite element solution of the same belt-drive. Excellent agreement in predicted results is found. Due to the presence of arbitrarily large system rotations and a numerically-friendly friction law, the analytical solution presented herein is recommended as a convenient comparison test case for validating friction-enabled dynamic finite element schemes.