Temperature-induced variations in magneto-viscoelastic behavior of magnetorheological elastomers: an experimental study

Magnetorheological elastomers (MREs) are a type of smart material that has gained considerable attention in recent years. Upon exposure to an external magnetic field, MREs provide instant variations in their viscoelastic properties (storage and loss moduli). MREs also exhibit magnetostriction effect and thus actuation properties under applied magnetic field. With these promising characteristics, MREs are increasingly integrated into engineering applications such as adaptive vibration isolators and absorbers, soft robotic actuators, bioengineering, and many others. Consequently, it is of paramount importance to characterize the response of MREs under varying environmental conditions. This paper aims to experimentally investigate the effect of temperature on the magneto-viscoelastic response of MREs. To this end, a cylindrical MRE sample with a 30% volume fraction of carbonyl iron particles (CIP) embedded within an Ecoflex^TM 00- 10 matrix was fabricated and tested in shear mode using magnetorheometer. To observe the effect of temperature on the storage and loss shear moduli, displacement sweep and frequency sweep tests were conducted over a temperature range of -10 to 30 °C under different applied magnetic flux densities. The results revealed that, interestingly, for this particular type of MRE, stiffness increases with rising temperature. This phenomenon is discussed in terms of entropy-related and enthalpy-related energy components, with the overall behavior of the MRE being determined by which energy component dominates as temperature changes. Additionally, operational conditions such as frequency and magnetic induction strength may influence the interaction between these energy components and thus affect the overall trend of material behavior with respect to temperature variation. Consequently, this paper emphasizes the importance of understanding how temperature affects MRE responses, which is essential in the context of modeling and practical applications of MRE composites.