基于多孔泡沫金属的磁流变液阻尼器关键机理及性能研究

发布时间：2019-01-12 15:40

【摘要】：机械振动无处不在，研究如何减小机械振动是一个重要的课题。常用的阻尼器一般通过自身储存和消耗振动能量的方式进行减振，缺乏自我调节能力。为此，迫切需要一种具有良好可控性和非线性特征的智能阻尼器。磁流变液阻尼器是一种可以通过调节外加电流的大小控制阻尼力的智能器件。目前关于磁流变液阻尼器减振的研究主要集中在控制阻尼力较大的振动，而对一些需要较小阻尼力的振动研究较少。而且，传统磁流变液阻尼器的工作缸内部需要充满磁流变液，为防止泄漏需要专门设计相应的密封装置；同时，磁流变液中硬质磁性颗粒的存在不可避免的会与密封装置产生摩擦，从而对阻尼器造成磨损，影响了其使用寿命。以国家自然科学基金项目和上海市联盟计划项目为背景，论文针对将孔泡沫金属应用于磁流变液阻尼器的关键机理展开研究，开发了一款基于多孔泡沫金属的磁流变液阻尼器，并设计了其性能测试系统，对所开发的阻尼器的性能进行了测试。研究的主要内容如下： ①研究了磁流变液在多孔泡沫金属中的流动从计算流体动力学基本控制方程出发，基于磁流体动力学和麦克斯韦方程，建立了磁流变液在泡沫金属中流动的控制方程；应用有限体积法，模拟仿真了磁流变液在多孔泡沫金属中的流动，得到了压强和速度分布。 ②分别从理论和实验两个方面研究了磁流变液的法向应力将磁流变液简化为椭圆球状，建立了磁场能量法的磁流变液法向力模型。为研究磁流变液的静态法向力和稳态剪切法向力，利用平行板型流变仪，首先研究了测试时间、磁场强度和温度对静态法向力的影响，而对于剪切模式下的稳态法向力，还研究了其与剪切速率的关系。同时，还研究了间距与磁场强度的关系，分别将平均稳态法向力和剪切应力、静态法向力和稳态法向力进行了比较，并从磁性颗粒微观结构演变的角度，阐释了磁场作用下磁流变液法向力的产生机理。 ③研究了储存在泡沫金属中磁流变液的法向力在研究磁流变液法向力基础上，利用平板型流变仪实验研究了测试时间、磁场强度、温度、剪切应变及振荡频率对储存在多孔泡沫金属中磁流变液静态法向力和振荡剪切法向力的影响。 ④研制了一套多孔泡沫金属磁流变液阻尼器样机研制了一种基于多孔泡沫金属的磁流变液阻尼器，不仅结构简单，成本低，而且可以防止泄漏，适用于小阻尼力的减振。详细阐述了阻尼器的结构和工作原理，并对磁阻进行了计算；然后，利用有限元仿真得到阻尼器内部的磁场分布，详细分析并讨论了电流、泡沫金属及泡沫金属材料对磁场强度的影响；最后，通过计算不同泡沫金属材料对剪切间隙内部磁阻的影响，分析了孔泡沫金属磁流变液阻尼器的磁特性。 ⑤研究了多孔泡沫金属磁流变液阻尼器的力学性能及动态响应时间针对多孔泡沫金属磁流变液阻尼器，自行设计并搭建了一套性能测试系统。实验研究了外部电流、剪切速度、多孔泡沫金属材料与阻尼力及响应时间的关系，同时，还研究了剩磁对力学性能的影响；基于牛顿第二定律建立了动态响应时间计算模型，通过一个动态响应时间的算例，分析了影响动态响应时间误差的原因。 ⑥研究了多孔泡沫金属磁流变液阻尼器的阻尼力特性，建立了神经网络模型针对模拟仿真和实验结果，根据牛顿第二定律及伯努利方程，推导了磁流变液在泡沫金属中流动的能量损失方程，，得到了局部水头损失和沿程损失，发现局部能量损失是机械能损失的主要原因。利用将多孔泡沫金属里的磁流变液等效为环形体积的方法，得到了产生磁流变液效应的有效磁流变液体积，推导了多孔泡沫金属磁流变液阻尼器的阻尼力计算模型。最后，根据阻尼力特性，结合实验数据，利用BP神经网络，建立了阻尼器的神经网络模型。结果表明，利用神经网络模型预测得到的阻尼力与实验结果吻合较好。
[Abstract]:Mechanical vibration is everywhere, and it is an important subject to study how to reduce mechanical vibration. The commonly used dampers are generally damped by their own storage and vibration energy, and lack of self-regulation. To this end, there is an urgent need for an intelligent damper with good controllability and non-linear characteristics. The magneto-rheological fluid damper is an intelligent device which can control the damping force by adjusting the magnitude of the applied current. At present, the research on the damping of the damper of the magneto-rheological fluid is mainly focused on the control of the large vibration of the damping force, while the research on the vibration of the damper with smaller damping force is less In addition, the inner part of the working cylinder of the traditional magneto-rheological fluid damper needs to be filled with the magnetorheological fluid, so that the corresponding sealing device is specially designed to prevent the leakage; meanwhile, the existence of the hard magnetic particles in the magnetorheological fluid is inevitable, the friction is generated by the sealing device, and the abrasion of the damper is caused Loss, affecting its use life Based on the project of National Natural Science Foundation of China and the project of Shanghai Alliance, the paper has developed a magneto-rheological fluid damper based on porous foam metal for the research of the key mechanism of applying the porous foam metal to the magnetorheological fluid damper. Test system for performance of developed dampers in the main part of the study. The capacity of the magneto-rheological fluid in the porous foam is studied as follows: From the basic control equation of the computational fluid dynamics, the flow of the metal is based on the magnetohydrodynamic and Maxwell equations, and the magneto-rheological fluid is established in the foam metal. The flow control equation is applied, and the flow of the magneto-rheological fluid in the porous foam metal is simulated by the finite volume method. The pressure and velocity distribution are studied from two aspects: theory and experiment, respectively. The magnetic rheological fluid is simplified into an elliptical spherical shape by the normal stress of the magneto-rheological fluid, and the energy of the magnetic field is established. In order to study the static and steady-state shearing method of the magneto-rheological fluid, the influence of the test time, the magnetic field strength and the temperature on the static method is first studied. The relation between the distance and the magnetic field strength is also studied. The mean steady-state method is also used to compare the force and shear stress, the static method to the force and the steady-state method, and from the angle of the microstructure evolution of the magnetic particles, the magnetic field under the action of the magnetic field is explained. The mechanism of the flow of the rheological fluid to the force. The method of applying the magneto-rheological fluid to the foam metal is based on the study of the force of the magneto-rheological fluid, and the plate-type rheometer is used to experiment. The test time, the magnetic field strength, the temperature, the shear strain and the oscillation frequency are studied to keep the magneto-rheological fluid in the porous foam metal. The Influence of the State-to-State Method on the Force and the Shear Force of the Oscillating Shear A porous foam metal-based magneto-rheological fluid damper is developed, which is simple in structure and low in cost. The structure and working principle of the damper are described in detail, and the magnetic resistance is calculated; then, the magnetic field distribution inside the damper is obtained by using the finite element simulation, and the current and the foam gold are analyzed in detail. and finally, the influence of different foam metal materials on the internal resistance of the shearing gap is calculated, The magnetic properties of the porous foam metal magneto-rheological fluid damper are analyzed. The mechanical properties and dynamic response time of the foam metal magneto-rheological fluid damper are based on the porous foam metal The relationship between the external current, the shear rate, the porous foam metal material and the damping force and the response time is studied, and the influence of the remanence on the mechanical properties is also studied. State response time calculation model, through a dynamic response In this paper, the reason of the time error of dynamic response time is analyzed, and the porous bubble is studied. The damping force characteristics of a metal-metal magneto-rheological fluid damper are established, and a neural network model is established to simulate the simulation and the experimental results, according to the Newton's second law and the primary The energy loss equation of the flow of the magneto-rheological fluid in the foam metal is derived, and the local water head is obtained. The main reason for the loss of mechanical energy is that the loss of the mechanical energy is the main cause of the loss of mechanical energy. The effective magneto-rheological fluid for generating the effect of the magneto-rheological fluid is obtained by the method of the equivalent of the magneto-rheological fluid in the porous foam metal to the annular volume. In this paper, the damping force calculation model of the porous foam metal magneto-rheological fluid damper is derived, and finally, the damping force calculation model of the porous foam metal magneto-rheological fluid damper is combined, In this paper, the neural network model of the damper is established by using the BP neural network.
【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TB535.1

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