A thermodynamic approach to field-induced stresses in electro- and magnetoactive composites

An equilibrium thermodynamic approach is employed to derive a continuum-lev el expression for the field-induced stress in uniaxial anisotropic material s, such as electro- and magnetorheological suspensions. This model introduc es new electro-and magnetostriction coefficients, which are material parame ters that describe the strain dependence of the dielectric and permeability tensors as well as the field-induced stresses. An idealized microscopic mo del illustrates the relationships between microscopic parameters and the ma croscopic magnetostriction coefficients. The model is used to determine the stresses in common applications; predictions from the continuum approach a gree with direct calculations of the normal stress and static shear modulus of magnetorheological suspensions.