A novel approach to investigate effect of magnetic field on dynamic properties of natural rubber based isotropic thick magnetorheological elastomers in shear mode

Abstract

The preparation of natural rubber based isotropic thick magnetorheological elastomers (MRE) was focused on by varying the percentage volume concentration of carbonyl iron powder and developing a test set up to test the dynamic properties. Effect of magnetic field on the damping ratio was studied on the amplification region of the transmissibility curve. The viscoelastic dynamic damping nature of the elastomer was also studied by analyzing the force-displacement hysteresis graphs. The results show that MR effect increases with the increase in magnetic field as well as carbonyl iron powder particle concentration. It is observed that softer matrix material produces more MR effect. A maximum of 125% improvement in the loss factor is observed for the MRE with 25% carbonyl iron volume concentration. FEMM simulation shows that as carbonyl iron particle distribution becomes denser, MR effect is improved. FEMM analysis also reveals that if the distance between the adjacent iron particles are reduced from 20 μm to 10 μm, a 40% increase in stored energy is observed.

Dynamic deformation–dependent magnetic field–induced force transmissibility characteristics of magnetorheological elastomer

“…The FT measurements are performed under steady-state harmonic excitation as the frequency sweep causes errors in acquired signal as discussed in our previous work (Hegde et al, 2014). The measurements are carried at the low-frequency region, which include 6, 10, 20, 25, 40, 50, 60, 70, and 80 Hz.…”

“…Displacement transmissibility is preferred when the device is to be protected from the vibrations arising from the point of attachment. The force transmissibility (FT) is the ratio of force at the output side to the input side (Hegde et al, 2014) and it is considered when the source of vibration is to be isolated from the system of concern. Both approaches have the same response function but differ with the system of reference (Rao, 2004).…”

An experimental investigation on the matrix dependent rheological properties of MRE

“…The ratio of force at output to force at input side was measured using a steady-state sinusoidal input since the frequency sweep generates errors in the collected signal, as we previously mentioned (Hegde et al, 2015). At frequencies of 40-200 Hz in steps of 20 Hz, measurements were taken.…”

“…The signals from the accelerometer and force sensor are acquired at a rate of 25.6 kS/s using a 24-bit NI 9234 data-acquisition module. To exclude the temperature effects, all tests were performed under room temperature conditions.The ratio of force at output to force at input side was measured using a steady-state sinusoidal input since the frequency sweep generates errors in the collected signal, as we previously mentioned(Hegde et al, 2015). At frequencies of 40-200 Hz in steps of 20 Hz, measurements were taken.…”

Magnetic field and frequency dependent LVE limit characterization of magnetorheological elastomer

“…Apart from exhibiting the properties of traditional filled elastomer, activation of magnetic domains of ferromagnetic fillers alter the stiffness and damping properties of MRE when exposed to post cured magnetic field [5,6].This field induced variation in the properties of MRE is referred to as MR effect [6,7]. The MR effect of MRE is mainly governed by the type and volume fraction of filler particles [6,8,9], type of matrix [10] and the magnetic field strength [11].…”