考虑界面相作用的磁流变弹性体模型的建立和实验分析

发布时间：2018-04-23 12:15

本文选题：磁流变弹性体 + 磁偶极子　；参考：《合肥工业大学》2017年硕士论文

【摘要】：磁流变弹性体是由铁磁性颗粒和橡胶类基体组成的智能材料,目前,研究磁流变弹性体的力学模型主要是磁偶极子模型以及修正的磁偶极子模型,这些模型考虑了颗粒之间的相互作用,尚未涉及颗粒和基体之间的相互作用。本文考虑到颗粒和基体之间的相互作用,计算出不同强度界面磁流变弹性体的力学性能,当应变幅值较小时,颗粒之间的界面相切应力比较小,颗粒完好无损,结合方式主要是强结合界面;当应变幅值继续增加,能够克服基体的屈服应力后,磁流变弹性体内部发生滑移,界面相的结合强度开始减弱,形成弱结合界面。论文主要工作内容包括以下四个方面:(1)介绍磁流变弹性体及其应用,由于磁流变弹性体剪切模量具有磁场可控性,被广泛应用到汽车减振机构、动态吸振器、缓冲隔振机构中;对国内外理论研究现状进行了分析综合,将现有的理论模型分为三大类:唯象模型、磁偶极子模型、连续介质模型,比较了三者的优缺点。(2)针对界面相效应,着重分析了不同应变幅值对界面结合强度的影响,将界面主要分为强结合界面和弱结合界面。对Eshelby等效夹杂理论和Mori-Tanaka两种典型的方法进行详细分析,指出前者适用于研究单个夹杂引起复合材料性能的变化,没有考虑到夹杂间的相互影响,后者考虑到这个问题,但是没有考虑界面弱化后对材料力学性能的影响。(3)针对不同界面结合强度对磁流变弹性体力学性能的影响,提出一种界面相模型,并计算出强结合界面的模量和阻尼特性,考虑到界面弱化的影响,进行了修正,计算出弱结合界面磁流变弹性体的模量特性和弱化后的界面阻尼;根据混合率准则,推导出无场下具有不同界面结合强度磁流变弹性体的模量和阻尼特性。关于磁流变弹性体的磁致效应,利用磁偶极子模型和修正的磁偶极子模型进行补充。(4)分别在有场和无场下制备四组不同颗粒含量硅橡胶基的磁流变弹性体,并对其微观结构进行观察,有场下颗粒之间形成有序的链状结构,无场下对于颗粒含量较高的磁流变弹性体内部则呈现规则化密布排列。通过动态机械分析仪测试磁流变弹性体的力学性能,同时结合推导出的力学公式,分析模量、阻尼和不同磁场强度、颗粒含量、应变幅值的关系,将实验结果和理论结果进行对比分析,验证了所提模型的有效性。
[Abstract]:Magnetorheological elastomer is a smart material composed of ferromagnetic particles and rubber matrix. At present, the mechanical model of magneto-rheological elastomer is mainly magnetic dipole model and modified magnetic dipole model. These models take into account the interaction between particles but not between particles and matrix. In this paper, considering the interaction between particles and matrix, the mechanical properties of magneto-rheological elastomer with different strength are calculated. When the strain amplitude is small, the interfacial shear stress between particles is small and the particles are intact. When the strain amplitude continues to increase, the matrix yield stress can be overcome, the internal slip occurs, the bonding strength of the interface phase begins to weaken, and the weak bonding interface is formed. The main work of this paper includes the following four aspects: 1) introduce Mr elastomer and its application. Because the shear modulus of MRE has magnetic field controllability, it has been widely used in automobile vibration absorber, dynamic vibration absorber and buffer isolation mechanism. The current theoretical models are divided into three categories: phenomenological model, magnetic dipole model and continuum model. The advantages and disadvantages of the three models are compared. The influence of different strain amplitudes on the bonding strength of the interface is analyzed. The interface is mainly divided into strong bound interface and weak bonding interface. The Eshelby equivalent inclusion theory and two typical methods of Mori-Tanaka are analyzed in detail. It is pointed out that the former is suitable for studying the change of composite properties caused by a single inclusion without considering the interaction between inclusions, and the latter for this problem. However, the effect of interface weakening on the mechanical properties of materials is not considered. (3) aiming at the effect of different interface bonding strength on the mechanical properties of magneto-rheological elastomer, an interface phase model is proposed, and the modulus and damping characteristics of strongly bonded interface are calculated. Considering the influence of interface weakening, the modulus properties of weakly bonded interface magneto-rheological elastomer and the interface damping after weakening are calculated, according to the mixing rate criterion, The modulus and damping properties of magneto-rheological elastomers with different interfacial bonding strength without field are derived. On the magnetoelectric effect of magneto-rheological elastomer, four groups of magneto-rheological elastomers with different particle contents were prepared by using magnetic dipole model and modified magnetic dipole model. The microstructure was observed. There were orderly chain structures between particles in the field and regular and dense arrangement in the magneto-rheological elastomer with high particle content in the absence of the field. The mechanical properties of magnetorheological elastomer were measured by dynamic mechanical analyzer. At the same time, the relationship between modulus, damping and different magnetic field intensity, particle content and strain amplitude was analyzed. The experimental results are compared with the theoretical results to verify the validity of the proposed model.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB381

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