MAGNETORHEOLOGY OF FERROFLUID COMPOSITES

Composites consisting of nonmagnetic particles with sizes in the micro n range suspended in a ferrofluid constitute an inverse magnetorheolog ical fluid. Structuring occurs in an applied magnetic field and can re sult in the solidification of the composite. Above a critical level of applied stress the material further transforms to a liquid state. Dat a confirming the existence of a solidified state are presented based o n constant shear theological measurements. Measurements of the yield s tress compare favorably with predictions of theory based on the analys is of unsymmetric stresses in the unyielded, anisotropic medium.