A study on torsional vibration attenuation in automotive drivetrains using absorbers with smooth and non-smooth nonlinearities
journal contributionposted on 2016-10-12, 12:32 authored by Ahmed Haris, Eliot Motato, Stephanos TheodossiadesStephanos Theodossiades, Homer Rahnejat, P. Kelly, A.F. Vakakis, L.A. Bergman, D.M. McFarland
The automotive industry is predominantly driven by legislations on stringent emissions. This has led to the introduction of downsized engines, incorporating turbocharging to maintain output power. As downsized engines have higher combustion pressures, the resulting torsional oscillations (engine order vibrations) are of broadband nature with an increasing severity, which affect noise and vibration response of drive train system. Palliative devices, such as clutch pre-dampers and dual mass flywheel have been used to mitigate the effect of transmitted engine torsional oscillations. Nevertheless, the effectiveness of these palliative measures is confined to a narrow band of response frequencies. Studying nonlinear targeted energy transfers is a promising approach to study vibration mitigation within a broader range of frequencies, using nonlinear vibration absorbers (or nonlinear energy sinks – NESs). These devices would either redistribute vibration energy within the modal space of the primary structure thus dissipating the vibrational energy more efficiently through structural damping, or passively absorb and locally dissipate a part of this energy (in a nearly irreversible manner) from the primary structure . The absence of a linear resonance frequency of an NES, enables its broadband operation (in contrast to the narrowband operation of current linear tuned mass dampers). Parametric studies are reported to determine the effectiveness of various smooth or non-smooth nonlinear stiffness characteristics of such absorbers. A reduced drivetrain model, incorporating single and multiple absorber attachments is used and comparison of the predictions to numerical integrations proves its efficacy.
The authors wish to express their gratitude to the EPSRC for the financial support extended to the “Targeted energy transfer in powertrains to reduce vibration-induced energy losses” Grant (EP/L019426/1), under which this research was carried out. Thanks are also due to project partners; Ford Motor Company and Raicam Clutch for their support.
- Mechanical, Electrical and Manufacturing Engineering