Vibration Analysis of Powertrain Mounting System with a Combination of Active and Passive Isolators with Spectrally-varying Properties

Abstract

Most of the prior work on active mounting systems has been conducted in the context of a single degree-offreedom even though the vehicle powertrain is a six degree-of-freedom isolation system.We seek to overcome this deficiency by proposing a new six degreeof-freedom analytical model of the powertrain system with a combination of active and passive mounts. All stiffness and damping elements contain spectrallyvarying properties and we examine powertrain motions when excited by an oscillating torque. Two methods are developed that describe the mount elements via a transfer function (in Laplace domain). New analytical formulations are verified by comparing the frequency responses with numerical results obtained by the direct inversion method (based on Voigt type mount model). Eigensolutions of a spectrally varying mounting system are also predicted by new models. Complex eigenvalue problem formulation with spectrally-varying properties provides a closer match with experimental results than the real eigenvalue formulation with frequencyindependent mounts. Given the spectral variance in the mount properties, a simple roll mode decoupling scheme is suggested for the powertrain isolation system. Then, the role of active path is clarified by comparison with no actuator operation.Multi-dimensional motions (especially coupling) are predicted and in particular the effects of active mount parameters such as the orientation angle, location and actuator input are investigated from the motion coupling perspective.

Refined response axis decoupling axiom for a coupled vibrating system with spectrally-varying mount properties

“…The problem with spectrally-varying mount properties requires a new analytical framework. To overcome this void in the literature, Park and Singh (2009, 2010) investigated the complex eigensolutions and frequency responses of the powertrain system with passive and active mounts in the presence of rigid base, and proposed a special TRA decoupling condition for such problems and achieved a complete decoupling between roll and other rigid body motions. However, their method is only valid for a special class of problems (in the focalized mounting scheme by placing the mounts with k(ω) and c(ω) in the vertical direction and located at the same height as the center of gravity of powertrain), and their approximation cannot be extended to a more general spectrally-varying vibrating system.…”