高稳定性磁流变液的试验及力学性能研究

发布时间：2019-03-24 12:46

【摘要】：磁流变液是由微米级的或纳米级的磁性颗粒均匀分散在基液中而形成的悬浮状液体,其主要成分为磁性颗粒、载液以及各种添加剂。在外加磁场的作用下,可在瞬间(毫秒级)迅速从流动的液体状态转变为类固体状态,且在撤去磁场后能够再次恢复流动状态。磁流变液的这种流变特性可以被用来设计磁流变阻尼器。磁流变液作为一种新型的智能材料,其智能可调的特性使磁流变阻尼器具有阻尼出力大、能耗少、实时控制、精度高等优点,从而具有良好的减震效果。因此磁流变液的性能优劣将直接影响到磁流变阻尼器能否正常发挥作用。为使磁流变阻尼器达到上述优点,磁流变液应具有稳定性好、不易团聚、零场粘度低、剪切屈服应力高等特点。目前,国内外的科研人员对磁流变液进行了很多研究,也取得了一定的成果,但制备高性能磁流变液、建立描述磁流变液磁流变行为的微观模型、设计剪切屈服应力测试装置等方面仍然有一些问题亟待解决,磁流变液的研究工作仍需进一步开展与深入。本文采用试验与理论结合、宏观与微观并举的研究方法,从磁流变液的基本性能出发,研究了磁流变液的制备方法、流变特性和力学行为,配制了高稳定性的磁流变液,提出了加入碳包覆颗粒的磁流变液初始倾斜链式模型,完善并发展了磁流变液剪切屈服应力一体化测试装置。本文涉及到铁磁力学、流体力学、电磁学、材料化学等学科领域,并通过试验观察和理论分析,得到了一些具有一定参考价值的结论。本文的研究工作主要表现为以下几个方面：1)制备了多壁碳纳米管包覆磁性颗粒,研究各项材料的用量以及制备过程,优选出具有最佳包覆效果的复合磁性颗粒；2)将制备的多壁碳纳米管包覆磁性颗粒与课题组先期研制的表面活性剂改性磁性颗粒相结合,并通过采用不同的体积分数与加入不同量的添加剂,研制了不同配比的磁流变液；3)对所研制的磁流变液进行稳定性、零场粘度以及剪切屈服应力测试,研究了两种复合磁性颗粒的用量比例、磁性颗粒体积分数、添加剂用量对磁流变液性能的影响,得到了各项指标均良好的磁流变液,并验证了多壁碳纳米管包覆磁性颗粒的加入对提高磁流变液稳定性的有益作用；4)基于磁流变液的工作模式改进设计了一种平行碟片式磁流变液剪切屈服应力一体化测试装置,通过对装置材料、构造、传感器以及数据采集的研究,发展了磁场均匀、使用方便的一体化测试装置；5)根据磁流变液的成链规律与链化机理,基于偶极子理论,推导了加入碳包覆颗粒的磁流变液初始倾斜链式模型,从微观层面分析磁感应强度、体积分数等因素对剪切屈服应力的影响,并将该模型的理论分析结果与试验结果进行对比,验证了加入碳包覆颗粒的磁流变液初始倾斜链式模型的正确性。本文的创新之处在于：1)制备了多壁碳纳米管包覆磁性颗粒,并将其与表面活性剂改性磁性颗粒一起作为混合磁性颗粒来研制磁流变液,测试结果表明多壁碳纳米管包覆磁性颗粒的加入能够提高磁流变液的稳定性,同时得到了两种磁性颗粒的用量比例对磁流变液沉降率、零场粘度的影响：2)完善并发展了一种平行碟片式磁流变液剪切屈服应力一体化测试装置;3)提出了加入碳包覆颗粒的磁流变液初始倾斜链式模型,并与试验结果进行对比验证。
[Abstract]:The magneto-rheological fluid is a suspended liquid formed by uniformly dispersing the magnetic particles of the micron or nanometer level in the base liquid, the main components of which are magnetic particles, a carrier liquid and various additives. Under the effect of the applied magnetic field, the flow state can be rapidly changed from the flowing liquid state at the instant (millisecond level), and the flow state can be recovered again after the magnetic field is removed. Such rheological properties of the magnetorheological fluid can be used to design the magnetorheological damper. As a new type of intelligent material, the magnetorheological fluid has the advantages of large damping output, less energy consumption, real-time control, high precision and the like, and has good damping effect. Therefore, the performance of the magneto-rheological fluid will directly affect the ability of the MR damper to function normally. In order to make the magneto-rheological damper achieve the above-mentioned advantages, the magnetorheological fluid should have the characteristics of good stability, difficult agglomeration, low zero field viscosity, high shear yield stress and the like. At present, the researchers at home and abroad have made a lot of research on the magneto-rheological fluid, and some results have been obtained, but the high-performance magneto-rheological fluid is prepared, and the micro-model for describing the magneto-rheological behavior of the magneto-rheological fluid is established. There are still some problems to be solved in the design of shear yield stress testing device, and the research work of the magneto-rheological fluid still needs to be carried out further and in-depth. In this paper, the method of preparation, rheological and mechanical behavior of the magneto-rheological fluid is studied from the basic properties of the magneto-rheological fluid by means of the combination of the test and the theory, the macroscopic and the micro-micro-simultaneous methods, and the magnetorheological fluid with high stability is prepared by the method, the rheological property and the mechanical behavior of the magnetorheological fluid, The initial inclined chain model of the magneto-rheological fluid with carbon-coated particles is put forward, and the integrated testing device for shear yield stress of the magneto-rheological fluid is developed and developed. This paper deals with the fields of ferromechanics, fluid mechanics, electromagnetics, material chemistry and so on, and has obtained some conclusions with certain reference value through experimental observation and theoretical analysis. The research work in this paper is mainly characterized by the following aspects:1) The preparation of multi-wall carbon nano-tube coated magnetic particles, the study of the dosage of each material and the preparation process, preferably the composite magnetic particle with the best coating effect; 2) the prepared multi-wall carbon nano-tube coated magnetic particles are combined with the surface active agent modified magnetic particles developed by the research group in advance, and the magnetorheological fluid with different proportions is prepared by adopting different volume fractions and adding different amounts of additives; 3) The stability, zero-field viscosity and shear yield stress of the developed magnetorheological fluid are tested, the influence of the dosage ratio of the two composite magnetic particles, the volume fraction of the magnetic particle and the dosage of the additive on the performance of the magneto-rheological fluid is studied, and the magneto-rheological fluid with good indexes is obtained, and 4) designing a parallel disk type magnetorheological fluid shear yield stress integrated test device based on the working mode improvement of the magnetorheological fluid, The research on the sensor and the data acquisition has developed an integrated test device with uniform magnetic field and convenient use, and 5) based on the chain-forming rule and the chain-forming mechanism of the magneto-rheological fluid, based on the dipole theory, the initial inclined chain model of the magneto-rheological fluid added with the carbon-coated particles is deduced, The influence of the magnetic induction intensity and volume fraction on the shear yield stress is analyzed from the micro-level, and the theoretical analysis results of the model are compared with the test results, and the correctness of the initial inclined chain model of the magneto-rheological fluid to which the carbon-coated particles are added is verified. The innovation of the invention is that:1) multi-wall carbon nano-tube-coated magnetic particles are prepared, and the magnetic rheological fluid is developed together with the surfactant-modified magnetic particles as mixed magnetic particles, The test results show that the addition of the multi-wall carbon nanotube coated magnetic particles can improve the stability of the magneto-rheological fluid, and at the same time, the influence of the dosage ratio of the two magnetic particles on the settlement rate and the zero-field viscosity of the magneto-rheological fluid is obtained. 2) Perfect and develop a parallel disk type magneto-rheological fluid shear yield stress integrated test device;3) put forward the initial inclined chain model of the magneto-rheological fluid to which the carbon-coated particles are added, and compare it with the test results.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB381;TB302

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