A tunable electromagnetic vibration absorber: Characterization and application

The paper presents a newly designed electromagnetic vibration absorber (EMVA), whose stiffness is on-line tunable. The EMVA is capable of suppressing vibration of the primary system excited by a harmonic force with a variable frequency. The EMVA consists of a clamped–clamped aluminum beam and a permanent magnet that is embedded in the center of the beam and placed between two poles of a C-shaped electromagnet. By varying the current of the electromagnet, stiffness of the EMVA can be adjusted instantaneously such that the absorber frequency can be tuned. A detailed characterization of the EMVA is presented. The effective stiffness of the absorber is determined numerically and validated experimentally. To test its effectiveness in vibration suppression, the EMVA is used to track two types of the exciting frequency variations: multi-step and linear. The response of the absorber mass is used to tune the EMVA to ensure that the absorber frequency equals the exciting frequency.