Compression properties of magnetostrictive polymer composite gels

In this research work, compression behavior of magnetostrictive silicone gels under the influence of an external magnetic field was investigated. Magnetostrictive gel specimens were made of silicon gel with 80% weight fraction of 3.8 mum embedded carbonyl iron particles. Compression tests were per-formed on cylindrical samples of these materials in the absence and in the presence of a magnetic field. It was found that the presence of a magnetic field would increase both the stiffness and the loadbearing capacity, but would reduce the maximum strain of the material. At 30% strain. a 50% increase in maximum stress in the presence of 0.32 T and 100% in stress in the presence of 0.44 T magnetic field inductions were observed. The induced mag-rietic force on the samples was also measured. The induced force decreased nonlinearly with the distance of the, electromagnet from the sample and increased nonlinearly with the magnetic induction. This research was oriented towards certain applications. These types of material characterization may provide useful information for potential applications of soft magnetostrictive elastomers in muscle type actuators and tunable stiffness elements. (C) 2004 Elsevier Ltd. All rights reserved.