Study On Mechanism Of Magnetorheological Elastomer Variable Stiffness And Applications

Magnetorheological elastomer(MRE) is a new member of Magnetorheological material and solid simulation of Magnetorheological fluid. It is mainly composed of rubber and magnetizable iron particles. The magnetizable particles disperse in the rubber and form ordered arrangement structure which takes root in the curing rubber under the external magnetic field. So MRE's mechanical, electric and magnetic properties can occur continuous, rapid and reversible change under the applied magnetic field. Because MRE has the controllable properties as the MR materials, at the same time the application equipments have the advantages of no sealing equipments, steady performance and rapid response etc, so it has the huge potential value in the vibration reduction and cushioning controlling area of aerospace, vehicle and civil structure.In this paper, the microcosmic model of MRE rheological effect is studied, the relationship between oblique angle of particles chains, magnetic field intensity, shear strain and MRE's shear modulus is also be calculated. On the basis of Kelvin model, the viscoelasticity model described the mechanical properties of MRE is improved. An isolation buffer based on MRE is designed and series of experiments are done to verify its performance, the specific contents include:â‘ Analyzed the ferromagnetic particles and matrix viscoelasticity of MR elastomer. On the basis of dipole and coupling field models, the influence to MRE's magneto-induced effect of three kinds of particles chains is get. The calculation results implicate that the MRE's magneto-induced effect will decrease while the oblique angle of particles chains increases. So certain measures should be taken to decrease the oblique angle of particles chains in the process of material production.â‘¡A macroscopic viscoelasticity parameter model described the mechanical performance of MRE is proposed, the magneto-induced shear modulus, loss modulus and loss gene of MRE are calculated on the basis of above model. By using the improvement dynamic mechanical analyzer, the magneto-induced shear storage modulus, loss modulus and loss gene of MRE sample are tested at different magnetic field and frequency and the experimental results implicate the rationality of viscoelasticity model.â‘¢By making use of variable stiffness properties of MRE, an isolation buffer based on MRE is designed and its isolation principle is analyzed. A single degree of freedom free-falling impact system is built, and the maximum response acceleration of MRE isolation buffer is tested at different falling highness and magnetic field. The experimental data implicate that the maximum response acceleration will decrease while the applied magnetic field increases. The goal of isolation buffer is achieved.