Investigating the performance of the magnetic vibration absorbers with numerical and experimental methods

Reducing the stress caused by external factors on buildings and other mechanical systems using non-linear vibration absorbers is one of the subjects that has been studied extensively. Nowadays, many vibration absorbers with non-linear stiffness elements have been developed which includes magnetic vibration absorbers. In this study, vibration attenuation performances of magnetic vibration absorbers with different tuning configurations against different types of disturbances is examined. Initially, non-linear stiffness that results from the repulsives force caused by facing identical poles of two magnets is investigated. Kinetic analysis of the magnetic vibration absorber is performed with the help of restoring force derived from this non-linear stiffness. Afterwards, a magnetic vibration absorber that features a wide spectrum of natural frequencies by adjusting distance between magnets, along with changable mass and damping level was designed and manufactured. This magnetic vibration absorber was tested experimentally by various disturbing frequencies and amplitudes. In these experiments, the behaviour of the magnetic vibration absorber against increasing amplitudes and frequencies was examined and the effect of parameters such as mass and damping level on this behaviour was investigated. In the following part of this study, dynamic responses of a primary building model with adjustable mass and natural frequency against sinusoidal and seismic inputs were obtained in absence of an effective damping method. Then, the magnetic vibration absorber was placed on the same primary building model and performances of the magnetic vibration absorber on building models with different natural frequencies against the same sinusoidal and seismic inputs were examined experimentally. In the end of every experiment, data measured by sensors which quantifies the destructive forces on the primary building were recorded. In the conclusion of this study, it was observed that the magnetic vibration absorber is capable of mitigating the responses of the primary buildings of different natural frequencies without requiring to re-tune. However, there are certain tuning parameters to consider if an effective absorbing performances for all types of inputs is desired. If these parameters is set correctly, efficiency of the magnetic vibration absorber is increased and improved attenuation is observed. Keywords: Magnetic vibration absorber, Eddy current damping, Tuned mass absorber, Non-linear stiffness