The Theoretical And Experimental Analysis Of Magnetorheological Elastomers Considering Interface Effect

Magnetorheological elastomer(MRE)is a kind of smart material,which is formed by penetrating magnetic particles in non-magnetic polymer matrix.The wide-used method for researching field-induced properties of MRE is almost based on the magnetic dipole.It calculated the field induced modulus by considering the interaction between two adjacent particles.However,there are very few modeling approach on the interaction between particles and matrix,i.e.the influence of different intensity of interphase on the rheological behavior.This thesis mainly studies the mechanic properties of MRE with different interface.The intensity of interface changes with the external stress.When exerted small stress,particles remain intact and the interface is strongly bonded.Gradually,the increasing stress reaches the critical resolved shear stress,some interface turns into weakly bonded and slip occurs in MRE.The main work of the thesis is embodied in four aspects:(1)MRE is applied to the automobile,vibration reduction,dynamic vibration absorber and buffer vibration isolation due to its rigidity and modulus are controllable by magnetic field.The current research of MRE mechanic properties are divided into three categories by generalizing the present state of theoretical research at home and abroad: phenomenological model,magnetic dipole model and continuum model.(2)The influence of different strain amplitude on the interface bonding strength are analyzed.Interface is mainly divided into strong interface and the weak interface.Eshelby equivalent inclusion theory and Mori-Tanaka method are detailed analyzed in detail.The former is applicable to study individual inclusions causing the performance change of composite material,without considering the mutual influence between the inclusion.Although the latter considers this problem,it did not consider after interface weakening effect on the properties of material mechanics.(3)According to the effect of different interface on the mechanic properties of MRE,an interface model is put forward.Based on Mori-Tanaka method,the modulus and damping characteristics of strong combination are calculated.Considering the weakening influence of the interface,Mori-Tanaka method is modified to calculate the modulus and damping of MRE with weak interface.According to rules of composite rate,the modulus and damping properties of MRE with different interface bonding strength are finally obtained.The magnetic effect are analyzed by magnetic dipole model and the modified magnetic dipole model.(4)MREs are fabricated with different material ratios and its microstructure observed.Particles form an orderly chain-structure with magnetic field and are densely distributed without magnetic field.The mechanic properties of MRE are tested by Dynamic Mechanical Analyzer.According to the deduced formula,the relationship of modulus,damping with different magnetic field intensity,particle content and strain amplitude are researched.Comparing experimental results with theoretical analysis,the effectiveness of the proposed model are well verified.