Transient Vibration Reduction Through the Use of Dual Absorbers

Abstract

Abstract The dual absorber configuration is shown to exhibit considerable improvements with respect to transient vibration over the conventional, single-absorber design for the same amount of total absorber mass. The term transient as used in this paper refers to monotonic changes in frequency during the start-up and shut-down of rotating machinery. The use of the frequency response as a design tool for this kind of transient is motivated by a quasi-staticity argument, which presumes the change in the operating frequency to be slow relative to the natural period of the oscillations. New tuning rules for dual absorbers are presented that yield near-optimal levels of transient vibration reduction along with significant steady-state attenuation. The improvements obtainable by using dual absorbers become more pronounced when the system changes its speed of rotation more slowly. The dual absorber design appears to exhibit the best overall vibration reduction characteristics among all passive absorbers tested and can also be installed retroactively onto an existing absorber setup. Because the design shares the simplicity of construction and maintenance of other passive absorbers, it is believed to be an excellent alternative to more complicated active or semi-active absorbers in many situations.