Nonlinear dynamics of one-way clutches and dry friction tensioners in belt-pulley systems

Serpentine belts are widely used for efficient power transmission in automobiles and heavy vehicles, but they suffer noise and belt wear problems that have their roots in system vibration. The primary goal of this work is to develop mathematical models for serpentine drives with nonlinear elements and implement vibration analysis to understand certain nonlinear dynamic behaviors, such as belt slip and premature belt fatigue, and provide guidance for practical design.; Nonlinear one-way clutches integrated with accessory pulleys are effective devices to decouple the motions of an accessory and its pulley during disengagements and mitigate the rotational pulley vibration problems. A mathematical model of a one-way clutch in belt-pulley systems is established, where a wrap-spring type of clutch is modeled as a nonlinear spring with discontinuous stiffness. Efficient methods such as multi-term harmonic balance, arclength continuation and numerical integration with attention to engagement/disengagement transition criteria are developed to analyze the clutch dynamics and clarify the behavior across important frequency ranges. Analysis of steady state and transient vibrations exhibits the mechanisms behind one-way clutches' effectiveness, and identifies where the one-way clutch works most effectively to reduce vibration and noise.; To explain the numerical results and clarify how design parameters affect the system dynamics, the method of multiple scales is employed to approximate the steady-state periodic solutions. The discontinuous separation function is expanded as a Fourier series in the perturbation analysis. The closed-form frequency-response relation is determined at the first order, and an implicit expression is obtained for the second-order approximation. This study evaluates the validity of the perturbation method for such strong nonlinearity through comparison of analytical and numerical solutions.; A one-way clutch that functions based on the relative velocity of the driven pulley and its accessory is common in applications. This type of one-way clutch is included in a hybrid continuum-discrete model incorporating span vibration and pulley rotation. This model is more accurate than the traditional spring-belt model with only pulley rotational degrees of freedom. The engagement/disengagement status transitions lead to a piece-wise linear system with alternate locked clutch and disengaged clutch configurations. Use of the transition matrix to evaluate the system response in discrete time series at each linear configuration saves computation time. (Abstract shortened by UMI.)...