Magnetomechanical behavior of Fe/PU magnetorheological elastomers

The elastic modulus and axial stiffness of the iron/polyurethane (Fe/PU) magnetorheological elastomers (MREs) have been investigated by a custom-made magnetic coil attached with a conventional universal testing machine. The size of the particle and sample dimension used in this study are 15 mu m and 75 x 12 x 12 mm(3), respectively. It has been observed that the regular arrangement of magnetic moments in Fe and its suspension in MREs leads to the enhancement of load-bearing capacity. Tensile behaviors of aligned and unaligned elastomer are compared and it is seen that the aligned elastomer has high stiffness than the unaligned elastomer. As a result, the stress amplitude increases and it indicates that the stiffness of the MREs can be increased by applying magnetic field. The atomic force microscopy confirms the presence of columnar structure of the magnetic moment in MREs. The MREs actuator is shown to be the ideal candidate for applications that require large strain at a specific high frequency.