Mechanical Properties of Soft Composites Fabricated from Two Different Magnetorheological Materials

Abstract

In this chapter there is a description of a soft composite that is fabricated from two different magnetorheological materials: magnetorheological elastomer (MRE) and magnetorheological fluid (MRF) and how its field-dependent mechanical property is experimentally investigated. Initially, an MRE skin is manufactured with two different void patterns of the rhombus and rectangular type. Then, the soft composite is fabricated by filling MRF into the voids and bonding the upper/lower MRE skins. Prior to testing, a scanning electron microscopy (SEM) image is taken to check the uniform dispersion of the carbonyl iron particle (CIP) of the MRE skin and observe the chain-like columns of the MRF due to the magnetic field. Subsequently, the force–displacement curve is directly measured from the tensile machine with three different design parameters: different void patterns of the MRE skin, CIP concentration of the MRE skin and the existence of the MRF in the void. It is identified from a comparative work among three different design parameters that the effect of the void pattern to the stiffness change (or effective Young's modulus (EYM)) is small, while the effect of the CIP concentration and MRF is significant. This result indicates that an appropriate composite showing a desirable tuning range of the stiffness can be fabricated using two different magnetorheological materials.