Preparation And Study On Mechanical Properties Of High-performance Mr Damping Gels

MR materials are usually mainly composed of matrix,magnetic particles and additives.The development of MR materials has formed a rich variety of material systems so far.Scholars at home and abroad have conducted a lot of research on MR materials,and have achieved many results.MR fluids(MRF)are the earliest developed MR material.In the subsequent research process,MR fluids gradually exposed its own problems such as easy settling,poor stability,easy wearing and oxidation of particles.Therefore,some scholars have successively improved the performance of MR fluids by selecting magnetic particles of different types and different treatment methods and adding various additives.Although a certain effect has been achieved,it cannot completely solve the problems exposed by the MR fluids.In order to solve the problems exposed by MR fluids,researchers used high molecular polymers(such as rubber)to replace the oil-based or water-based liquid matrix used in MR fluids,and solidified micronsized soft magnetic particles in them.Therefore MR elastomers(MRE)are obtained.Since the matrix used for MR elastomers is solid,the MR effect of MR elastomers is small,resulting in a small magneto-controllable range,thereby limiting the practical application of MR elastomers.The characteristics of MR gels(MRG)are between MR fluids and MR elastomers,which has the advantages of both.They solve the problem of sedimentation of MR fluids more effectively.They have higher shear yield stress,higher MR effect and wider magnetostrictive range than MR elastomers,so they can be widely used in some fields.Scientific and systematic test ideas are used to develop a kind of high-performance MR damping gels through the combination of test and theoretical analysis,macro and micro research methods.On the basis of solving the settlement problem,the shear yield strength and adjustability of the MR damping gels are improved,and the microscopic deformation mechanism of the MR damping gels is systematically explained.Then the related theoretical derivation is carried out.The theoretical values calculated by the model and test values are compared to verify the effectiveness of the model.The development of this article includes the following aspects:1)According to the characteristics of MR damping gels,suitable magnetic particles,matrixes with different viscosities and different types of surfactants are selected,and three series of MR damping gels samples are prepared combined with the development ideas of MR damping gels.2)With indicators such as settlement stability,zero-field viscosity,shear yield stress,and adjustability,the effects of matrix viscosities,surfactant types and combinations,and volume fractions of magnetic particles on the properties of MR damping gels are studied,and the relevant theories are applied to explain the mechanism.Then the best performance formula is determined through layers of screening.3)Based on the planar current loop model and coupled field theory,a micromechanical model of MR damping gels based on the planar current loop model is proposed,and the relationship between macro-mechanical indexes and changes of micro-particle structure is established.Then the theoretical values calculated by the model and test values are compared to verify the effectiveness and accuracy of the model.Innovations in this paper:1)The development idea of MR damping gels is established.A series of MR damping gels with different viscosities of matrix,different surfactant types and combinations,and different volume fractions of magnetic particles are prepared.The best performance formula is selected based on indicators such as settlement stability,zero-field viscosity,shear yield stress,and adjustability.Combined with the advantages and disadvantages of the existing adjustability index for MR materials,a more reasonable adjustability index is redefined;2)The planar current loop model replaces the magnetic dipole model theory for theoretical derivation,and a micro-mechanical model of MR damping gels based on the planar current loop model is proposed.The theoretical values calculated by the model and test values are compared to verify the effectiveness of the model.