A study of the magnetorheological effect of bimodal particle based magnetorheological elastomers

This paper presents theoretical and experimental studies of the mechanical performance and magnetorheological effects of magnetorheological elastomers (MREs) fabricated with mixtures of large and small particles. First of all, an effective permeability model was developed to theoretically analyze the MR effect of bimodal particle based MR elastomers. From the theoretical analysis, an optimum volume fraction was derived which resulted in enhanced MR effects. Two categories of iron products with different particle sizes of 50 and 5 mu m were used to fabricate a series of bimodal MRE samples. Their mechanical performances were characterized by using an MR rheometer. Experimental results agreed fairly well with theoretical analysis. The theoretical prediction of the optimum mixture ratio between large and small size particles was experimentally verified.