Controlling structure borne noise in automobiles using magnetorheological components

Car manufacturers are reducing the mass of automobiles in order to increase fuel efficiency. However, a lighter vehicle is more susceptible to structure borne noise, which can reduce a driver's safety due to fatigue. Magnetorheological components can semiactively reduce structure borne noise. This thesis describes two experiments: the fabrication of a bushing using magnetorheological fluid, and the creation of a magnetorheological elastomer using iron beads and silicone. The bushing had a negligible effect on the amplitude of the vibration except for a small change at the resonant frequency. The magnetorheological elastomer's resonant frequency changed significantly in the presence of a magnetic field. When the elastomer was cured within a magnetic field, so that the iron beads form chain-like structures, an even greater change in the modulus occurred. Additionally, results from further experiments show that the magnetic field orientation with respect to the direction of acceleration alters the magnetorheological effect.