| The purpose of this study is to develop a better understanding of transient oscillations in centrifugal pendulum vibration absorbers (CPVAs). A CPVA is a passive device that is used to reduce engine-order torsional vibrations in rotors; it generally consists of a mass that moves along a prescribed path relative to the rotor. The application currently being explored is to decrease torsional vibrations of crankshafts in multi-displacement automobile engines, and determine how CPVAs behave as loading conditions change. The system is modeled as an ideal rotor to which a set of tautochronic, that is, isochronous, CPVAs are attached. Relatively simple and accurate approximate expressions for the maximum transient amplitude of the absorber and the rotor vibration are obtained by considering the linearized system response, and by the method of averaging to a weakly nonlinear model. The results are confirmed by simulations of the full system model. The effects of absorber damping, absorber inertia, and absorber tuning on peak transient responses are investigated. It is shown that trade-offs must be considered when selecting these system parameters for optimal transient performance. |
