Dynamic Absorbers for Rotating Machinery

Dynamic absorbers are simple passive devices installed on mechanical systems to absorb and dissipate kinetic energy, thus reducing the amplitude of vibrations/oscillations. The most widely spread typologies of dynamic absorbers belong either to the family of the Tuned Mass Dampers (TMD) and Tuneable Liquid Column Dampers (TLCD). They are both based on an inertial element, represented by a rigid body (TMD) or a water volume (TLCD) and an elastic-damping element, which consists of the same water volume in the TLCD case. Dynamic absorbers are almost exclusively applied in large civil structures, such as tall buildings and electricity transmission cables. The scope of this paper is to investigate the possibility to use TMDs and TLCDs for the reduction of vibrations on rotating machines. The study, based on numerical simulations and on experimental tests on specifically designed test-rigs. This study will provide design guidelines, specific for the application of TMD and TLCD on rotating machines, and investigate the effectiveness and limits of the two families of dynamic absorbers. Optimal tuning parameters will be identified for the specific application either analytically or numerically, in order to maximize the effectiveness of the two devices for rotating machines. A comparison between the two absorbers will also be provided, in order to identify the most effective choice or combination of TMD and TLCD.