LAUSR

Abstract A theoretical dynamic model of vehicular driveline is presented to reveal the mechanism of low frequency interior booms within a low engine speed range. Unlike existing models, this model manifests the torsional-lateral-longitude coupling effects of the propeller shafts together with the integral rear axle assembly. Based on rotor dynamics, translational rigid body vibrations of propeller shafts due to flexible support onto the trimmed body are complemented to traditional one-dimensional torsional model. Then the kinematic equation of the Hooke’s joint is improved to illustrate the dynamic effects of the non-constant velocity coupling. In addition, pitching of the integral rear axle assembly coupled to torsional vibration through the main reducer is also considered. An application containing analyses of critical engine speed and dynamic response is performed to a rear-wheel-drive vehicle, which proves that this model shows the best balance of accuracy and efficiency compared with established models, and has a capacity to show the contributions of the Hooke’s joints. Finally, a modal sensitivity analysis is conducted to find the authentic cause of the vehicle’s boom and explain the reasons that the previous model is less accurate. At last, the sensitivity of peak value of force transmissibility is derived as a novel method to seek for optimized directions. It concludes that this model is suitable for investigation and optimizing of boom problems.