Magnetomechanical properties of magnetorheological composites
Paweł Małecki, Aleksandra Szewczyk, Jacek Pigłowski
Quarterly No. 1, 2013 pages 47-51
DOI:
keywords: carbonyl iron powder, chitosan, magnetorheological composites
abstract According to Takagi's definition, an intelligent material is able to react to external stimulus by a significant change in its properties in order to make a proper and successful response to the stimulus. The rheological behaviour of magnetorheological composites (MRC) can be controlled continuously, rapidly and reversibly by an applied magnetic field. In this paper, an acrylic copolymer with carbonyl iron powder (CIP) is tested in conditions of mechanical and magnetic stimulations. Chitosan-coated magnetic particles are made in order to change the hydrophilic surface character of CIP to hydrophobic and as a result, obtain better compatibility between the particles and the matrix. The test samples are subjected to cyclic shearing with a constant frequency of 1 Hz. The change in the magnetomechanical properties is expressed by the relative change in hysteresis loop area δW and stress amplitude δτ. An increasing content of carbonyl iron in the composites and the strength of magnetic field H causes an increase in the hysteresis loops area. Material containing modified particles has a significantly bigger hysteresis loop area than samples filled with unmodified carbonyl iron powder. Based on this knowledge, it can be concluded that this sample can dissipate much more mechanical energy.