Nonlinear Dynamic Analysis of a Morphing Pulley Belt Drive Transmission System (original) (raw)

This doctoral research presents nonlinear dynamic analyses of a morphing pulley belt drive transmission system. In a morphing pulley transmission system, different drive ratios are achieved by discretely varying the pulley diameter. The belt drive system consists of a tensioning mechanism, as well as a driver and driven pulley. A new approach is proposed for the tensioning mechanism to fulfill the performance requirements and ensure smooth shifts. However, the driven pulley typically possesses high inertial loads leading to excessive belt vibrations and failure due to fatigue. In addition, during a drive ratio shifting and the resulting change in the pulley diameter, the belt experiences sudden load variations causing excessive vibrations. To remedy these excessive vibrations, a one-way clutch in combination with a torque limiter is installed between the driven pulley and the load. This forms a nonlinear vibration reduction system that partial disengagements between the pulley and the accessory. Dynamic analysis is essential for designing a belt drive system. However, limited published work has been found providing a complete dynamic analysis of a morphing pulley system. This doctoral research provides a dynamic model of the morphing pulley transmission system using various tools and analysis approaches, namely the method of multiple scales, numerical techniques and experiments. Lagrange's energy method is used to obtain the equations of motion. A periodic solution under harmonic, resonant, and nonresonant excitations are achieved through the method of multiple scales. The effects of different design parameters on the system performance are studied for various harmonic excitations. The robustness of the proposed nonlinear vibration reduction approach is presented through its implementation in a belt drive system. III ACKNOWLEDGEMENTS I am heartily grateful to my supervisor, Professor Jean Zu, whose encouragement, guidance and support from the initial to the final stages enabled me to develop an understanding of the research. I am very grateful to my colleague Ali Sabti for his help and assistance throughout this project. My parents deserve special mention for their inseparable support and prayers. Words fail me to express my appreciation to my wife, Maryam, whose dedication, love and persistent confidence in me, has taken the load off my shoulder. Lastly, I offer my regards and blessings to all of my colleagues in Vibrations Dynamics and Mechatronics Laboratory (VDML) at the University of Toronto who supported me during my doctoral research.