Magnetorheological elastomer-based smart sandwich beams with nonconductive skins

The field-dependent dynamic flexural rigidity of a simply supported sandwich beam with a soft core composed of a magnetorheological elastomer (MRE) part and non-MRE parts is studied in this paper. The skins of the sandwich beam are nonconductive such that there are no magnetoelastic loads applied to the skins during vibration. The orientation of the chain-like structures inside the MRE part is perpendicular to the skins Such that the MRE part operates in shear mode. Due to such a configuration, the dynamic flexural rigidity of the sandwich beam can be controlled by applied magnetic fields due to the field-dependent shear modulus of the MRE part. Based on the Hamilton principle, a dynamic model of the proposed sandwich beam is developed. A simply supported beam excited by a vertical force, distributed uniformly in a narrow region around the center of the beam is simulated. The anti-resonant frequencies are found to change with the shear modulus of the MRE part up to 40%, while the resonant frequencies change only slightly. Although MRE is an extremely soft material with a zero-field shear modulus about 0.4 MPa, the results from the current research indicate that the sandwich configuration can well utilize the controllable properties of MRE to realize applicable semi-active devices with controllable stiffness