Pseudo-Villari Experimental Characterization of Magneto-Rheological Elastomers

Magneto-rheological elastomers (MRE) are composite materials with magnetically polarized particles dispersed in an elastomeric soft matrix. These materials are an important branch of the smart material family being the mechanical and rheological properties can be reversibly changed upon exposure to a magnetic field. Conversely, this multi-physics coupling shows also an inverse effect associating a dependence of magnetic induction field of a material on mechanical stress/strain and taking the name of pseudo-Villari effect. This paper describes an experimental characterization conducted on MRE with the aim of adopting these materials to make smart mounts to be used as vibration isolators and able at the same time to give useful information to monitor the component to be isolated. In the first part of the paper, the experimental procedures for making samples are described as well as the test bench. The samples are subjected to shear periodic loads, varying both the amplitude and the frequency of the excitation. The testing machine is equipped with an excitation coil, with which it is possible to vary the intensity of the magnetic field crossing the sample during testing and a search coil able to evaluate the pseudo-Villari effect