Correlation Between Temperature Changes and Magnetostrictions in Magnetorheological Foam

Abstract

Magnetorheological (MR) foam has been identified as a potential magnetostrictive material due to high flexibility and rapid responsiveness towards applied magnetic fields. However, to date, the effect of MR foam at different temperatures has not yet been discovered. Since most devices have tendency to experience raise in temperature during operating system, this might affect characteristics and magnetostriction performance of magnetostrictive material. Therefore, this study aimed to investigate the effect of temperatures between 25 to 50oC on magnetostriction of MR foam, at magnetic fields ranging from 0 to 0.7T. Two samples were prepared which were PU foam and MR foam. During off-state (0T), both samples has reduced in dimension, by about 0.03–0.04% at increasing temperatures from 25 to 35oC. Then, both samples experienced expansion in dimensions at temperatures between 35 to 50oC, by 0.06% and 0.04% for PU and MR foams, respectively. Meanwhile, at on-state (0.1 to 0.7T), similar trends were observed in which the transition from decreased to increase in magnetostrictions occurred at 35oC. The phenomenon is due to the soft-segment and hard-segment in the polymer matrix that have been affected, within the temperature ranges of 25-35oC and 35-50oC respectively, which caused the negative and positive magnetostrictions of both samples.