Magneto-rheological elastomer (MRE) is known as class of smart materials whose elastic property can be varied by the applied external magnetic field. For the use of semi-active vibration control, any kind of external sensor such as accelerometer or displacement sensor is usually used to monitor the real-time response of structures while leaving cost, proper installation and maintenance problems for real applications. In addition to the field-dependent stiffness change property of MRE, the electrical resistance of the composite is also changed by the induced strain within the elastomer providing a new self-sensing feature as a multifunctional material. In the present study, a novel dynamic vibration absorber having self-sensing function and adaptability using Magneto-rheological elastomer is developed. The natural frequency of the absorber is instantaneously tuned to a dominant frequency extracted from the strain signal. The damping performance of the absorber is investigated by applying the absorber to a fundamental base-excited 1-dof vibration system. Investigations show that the vibration of the target structure exposed to a non-stationary disturbance can be satisfactorily reduced by the proposed frequency-tunable dynamic absorber without the use of an external sensor, at the exceeding performance in comparison to conventional passive-type dynamic absorber.
Active Vibration Control of a Rotating Shaft Supported by Flexible Bearings. 1st Report. Application of the Principle of a Dynamic Absorber.