Effect of magnetorheological elastomer thickness and magnetic flux on vibrational characteristics

Abstract

The maximum vibration is achieved when the natural frequency of any vibrating device reaches its resonance value. In a conventional suspension system, springs are used as vibration absorber. Since the stiffness of the spring is constant and the natural frequency of the road surface could vary at some point, the natural frequency of the spring can become the same as the natural frequency of the road. This would lead to resonance, and the vibration would be maximum and hence discomfort for the passengers. There are many active vibration absorbers under testing and development to overcome this disadvantage. In this paper, one such alternate vibration absorber is studied. The vibration absorber analyzed here is a magnetorheological elastomer (MRE). Magnetorheological materials fall under the smart material category as they could exhibit different properties under different conditions. The MRE laminate containing silicone and carbonyl iron was prepared for 6, 8, and 10 mm in thickness and was cut to the required dimension. The vibration characteristics of the vibration absorber were analyzed with and without magnetic flux. Acceleration of the MRE laminate fixed in cantilever mode as a function of natural frequency for 6, 8, and 10 mm thick with and without magnetic flux. The natural frequency increases with increasing MRF composite thickness due to the increasing stiffness of the composite. With applying magnetic flux, the rise in natural frequency has increased for all thicknesses. It shows that the increase in natural frequency achieved by applying magnetic flux to a 10 mm thick laminate is greater. The natural frequency increases as the thickness increases for modes 1 and 2. The rise in natural frequency for mode 2 compared to mode 1 has increased for all thicknesses.