Field dependence of viscoelastic properties of MR elastomers

A magnetoactive elastomer made of micronic carbonyl iron particles, structured in elongated clusters and embedded in a silicon elastomer matrix is studied under traction both in static and dynamic modes, The application of a magnetic field of 120kA/m induces a change in elastic moduli of about 0.6MPa at strains of 4 to 5%. Still higher changes(4MPa) are observed in dynamic storage modulus at low strains (10(-4) to 10(-3)). The shape of the stress-strain curves are explained by taking into account the existence of a fiber like structure.