Performance improvement of the vibration reduction method by frequency-based sub-structuring and a neutralizer at vibration source device

摘要

Recently, machine structures consist of many subsystems. Vibration of the subsystems often propagates to a whole structure. As a result, unpleasant mechanical noise and vibration occur at the whole structure. And even if countermeasure at the whole structure is the most effective solution, the manufacturer of the subsystem will be required countermeasure at the subsystem. Normally, the subsystems are far smaller than the whole structure. Therefore, compliance of a subsystem is dominated by a rigid body mode at the interested frequency. In a case like this, it can be defined that, few degrees of freedom of transmitted forces dominate the resonance of the whole structure. In this study, a design method in the case that a single degree of freedom transmitted force is dominant is organized. A countermeasure method for vibration of a whole structure using FRF based sub-structuring and a Neutralizer at a single target frequency, with a restriction that only subsystems can be structurally modified, is proposed. As a result, vibration transmission and wave propagation from a subsystem to a whole structure at a target frequency are theoretically zero. And to improve the performance of this method, the position and the size of a Neutralizer on an active subsystem is studied.