Dynamic Characterization of Magneto-Rheological Elastomers in Shear Mode

The paper presents dynamic shear properties of magneto-rheological elastomers (MREs) under various loading conditions. It particularly focuses on characterization of MREs under compression-shear type combined loading, as it represents realistic loading conditions in various engineering systems and structures. In this study, MRE samples were fabricated by curing a two component elastomer resin with 30% content of 10 mu m sized iron particles by volume. In order to vary the magnetic field during shear testing, a test fixture was designed and fabricated in which two permanent magnets could be variably positioned on either side of the specimen. By changing the distance between the magnets, the fixture allowed for varying the magnetic field that passes uniformly through the sample. Using this test setup and a dynamic test frame, a series of shear tests of MRE samples was performed by varying the magnetic field and frequency of loading. The results show the MR effect (percent increase in the materials "stiffness") increases as the magnetic field increases and loading frequency increases within the range of the magnetic field and input frequency considered in this study. The results further show that the elastic modulus of the precompressed MREs increases as compared with that of MREs without precompression.