【作者】 王宁宁；

【导师】 刘新华；

【作者基本信息】 中国矿业大学 ， 机械制造及其自动化， 2021， 博士

【摘要】 磁流变液是一种新型的固-液两相智能材料,其工作机理受外加磁场控制和调节。磁流变传动是以磁流变液为动力和运动传递介质的一种新型传动技术,具有响应迅速可逆、控制简单、低能耗和抗干扰能力强等优点,在机电设备软启动、软制动、无级调速和过载保护等方面具有广泛的应用前景。针对磁流变液传动系统动力传递机理尚不清晰的问题,本文在以下几个方面开展了深入研究。研究了磁流变效应的作用机理,获取了磁场强度对磁流变效应的影响特征;分析了磁流变液的选材原则以及不同属性材料对磁流变液性能的影响特性,研究了磁流变液制备方法,制备出五种包含纳米Fe₃O₄球形导磁颗粒添加物的高性能磁流变液,并通过实验研究确定了磁流变液综合性能最佳时纳米Fe₃O₄球形导磁颗粒添加物的质量分数。通过理论分析获取了软磁性颗粒在磁场作用下所受的作用力以及软磁性颗粒体系所具有的能量,建立了软磁性颗粒的运动方程和软磁性颗粒体系的能量方程;研究了磁流变液微观结构演变特性的三维数值模拟策略和模拟加速方法,并分别对大颗粒数量磁流变液在不同磁感应强度下的微观结构演变特性进行了三维数值模拟,获取了不同颗粒数量的磁流变液在不同磁感应强度下的微观结构演变规律。设计了基于工业CT的磁流变液微观结构特性研究实验系统和实验方案,搭建了磁流变液工业CT扫描实验台,开展了不同颗粒体积分数的磁流变液在不同磁感应强度下的工业CT扫描实验,获取了磁流变液在磁场作用下的整体、局部以及样品内部的三维微观结构特征,定量捕捉到颗粒链长度的变化规律和软磁性颗粒体系的分布特点。研究了挤压强化技术在磁流变制动器中集成设计的工作模式和可行性,开发出一种新型挤压强化磁流变制动器,对其磁路进行了设计和分析,并通过电磁场仿真和实验验证了磁路设计的合理性,获取了各主要设计环节对工作间隙磁感应强度的影响规律。设计并搭建了磁流变液制动、挤压和温度测试实验系统,开展了挤压强化磁流变制动器的性能测试实验,获取了制动转矩在温度场上的映射特征,磁流变液温度在不同滑差功率和不同散热条件下的变化特点,制动转矩在不同挤压压强作用下的增强规律,以及挤压强化磁流变制动器在挤压作用下的工作性能,结果验证了所设计挤压强化磁流变制动器的可靠性和挤压强化技术集成设计的可行性。本文所取得的研究成果对于磁流变液传动系统动力传递机理的深入研究具有重要的指导意义,能够为大功率磁流变传动设备的研发和应用提供技术支持。本文共有图124幅,表22个,参考文献137篇。更多还原

【Abstract】 Magnetorheological fluids（MRFs）is a new kind of solid-liquid two-phase intelligent material,whose working mechanism is controlled and regulated by an external magnetic field.Magnetorheological（MR）transmission is a new type of transmission technology,which uses MRFs as power and motion transmission mediums,MR transmission has many advantages,such as a quick and reversible response,simple control and low energy consumption,as well as high anti-interference ability,etc.Therefore,it possesses a broad application prospect in the fields of soft start,soft brake,stepless speed control and overload protection for mechanical equipments.According to the problem of power transfer mechanism of MRFs transmission system is not clear,this dissertation conducts an in-depth research from the following aspects.The mechanism of MR effect is researched,the influence characteristics of magnetic field intensity on MR effect are obtained.The material selection principle of MRFs and the influence characteristics of materials with different properties on the performance of MRFs are analyzed,the preparation method of MRFs is researched,five types of high performance MRFs containing Nano-Fe₃O₄ spherical and magnetic particle additive are prepared,the mass fraction of Nano-Fe₃O₄ spherical and magnetic particle additive in MRFs with the best comprehensive performance is determined by experiments.The force of soft magnetic particle and the energy of soft magnetic particle system under the action of a magnetic field are obtained by theoretical analysis,the motion equation of soft magnetic particle and energy equation of soft magnetic particle system are established.A three-dimensional numerical simulation strategy of microstructure evolution characteristics for MRFs,and the acceleration method of the simulation are researched,the microstructure evolution characteristics of MRFs with large particle numbers under different magnetic induction intensities are numerically simulated in three dimensions,the microstructure evolution laws of MRFs with different particle numbers under different magnetic induction intensities are obtained.The experimental system and scheme for researching the microstructure characteristics of MRFs based on industrial CT are designed,an industrial CT scanning test bench for MRFs is established,the industrial CT scanning experiments of MRFs with different particle volume fractions under different magnetic induction intensities are conducted,the overall,local and internal three-dimensional microstructure characteristics of MRFs under the action of magnetic fields are obtained,the variation laws of particle chain lengths and the distribution characteristics of soft magnetic particles are quantitatively captured.The working mode and feasibility of the integrated design of squeeze-strengthening technology in MR brake are researched,a new type of squeeze-strengthening MR brake is developed,the magnetic circuit of the brake is designed and analyzed,the rationality of the magnetic circuit design is verified,and the influence laws of the main design parts on magnetic induction intensities of working gap are obtained by electromagnetic field simulations and experiments.The braking,squeezing and temperature test system for MRFs is designed,the performance test experiments of the squeeze-strengthening MR brake are conducted,the mapping characteristics of braking torques on temperature fields,the variation characteristics of MRFs temperature under different slip powers and different heat dissipation conditions,the enhancement laws of braking torques under different squeezing pressures,and the working performance of squeeze-strengthening MR brake under squeezing actions are obtained,the reliability of the designed squeeze-strengthening MR brake,and the feasibility of the integrated design of squeeze-strengthening technology in the MR brake are verified.Research results obtained in this dissertation play an important guiding significance to the thorough study of power transfer mechanism of MRFs transmission system,and provide a technical support for the development and application of high-power MR transmission devices.The dissertation has 124 figures,22 tables and 137 references.更多还原