This article is focused on the development and characterization of highly controllable magnetorheological materials for stiffness and damping control in semi-active control applications. Two types of magnetorheological materials are developed in-house: magnetorheological elastomer with soft base elastomer, and magnetorheological fluid encapsulated in regular elastomer, namely magnetorheological fluid-elastomer. In both cases of magnetorheological elastomers and magnetorheological fluid-elastomers, the samples are evaluated using in-house-developed shear and compression test rigs, which are equipped with electromagnets and Hall effect sensors for measuring the magnetic field. These features provide the capability to precisely control a wide range of magnetic fields during the experiments. In the case of magnetorheological elastomers, the experimental results of the in-house magnetorheological elastomers are compared with commercially available counterparts made of hard base elastomer. It is shown that the controllability of the material, that is, the relative magnetorheological effect, is significantly improved in the case of magnetorheological elastomer with soft base elastomer. In addition to various magnetic fields, the samples are subjected to a range of loading amplitudes and frequencies. A general trend is observed where the frequency and strain amplitude cause an opposite effect on both the shear and compressive moduli: the increase in frequency gives rise to a higher value of modulus whereas the increase in amplitude reduces the modulus. Furthermore, the effect of bonding on the performance of the magnetorheological elastomers in compression mode is evaluated and the results indicate a significant increase in the modulus and decrease in the loss factor. In all the cases, however, the change of loss factor does not exhibit a predictable trend as a function of magnetic fields. In order to investigate a magnetorheological-based solution for controlling the damping of a semi-active system, magnetorheological fluid-elastomer samples are made in-house. These samples are fabricated using three different iron concentrations, and are tested in compression (squeeze) mode. The results of these experiments confirm that the equivalent damping coefficient of the material rises with the increase in magnetic field, and this effect becomes stronger as the iron concentration of magnetorheological fluids increases. It is also demonstrated that the magnetorheological effect is highly dependent on the loading frequency and amplitude, where the equivalent damping coefficient decreases with the increase in loading frequency and amplitude. In all the aforementioned cases, the stiffness of magnetorheological fluid-elastomers exhibits minor changes, which offers the in-house-developed magnetorheological fluid-elastomers as a damping only control option, a development that is different from the magnetorheological fluid-elastomers reported in the literature.

中文翻译：

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压缩模式下高度可控磁流变材料的制备和表征

本文重点介绍半主动控制应用中用于刚度和阻尼控制的高度可控磁流变材料的开发和表征。内部开发了两种类型的磁流变材料：软基弹性体的磁流变弹性体和包裹在常规弹性体中的磁流变流体，即磁流变流体-弹性体。在磁流变弹性体和磁流变流体弹性体的两种情况下，使用内部开发的剪切和压缩试验台对样品进行评估，这些试验台配备有电磁铁和霍尔效应传感器，用于测量磁场。这些功能提供了在实验过程中精确控制大范围磁场的能力。在磁流变弹性体的情况下，内部磁流变弹性体的实验结果与由硬基弹性体制成的市售对应物进行了比较。结果表明，在磁流变弹性体与软基弹性体的情况下，材料的可控性，即相对磁流变效应得到显着提高。除了各种磁场外，样品还受到一系列载荷幅度和频率的影响。观察到一个普遍趋势，其中频率和应变幅度对剪切模量和压缩模量产生相反的影响：频率的增加会产生更高的模量值，而幅度的增加会降低模量。此外，评估了粘合对压缩模式下磁流变弹性体性能的影响，结果表明模量显着增加，损耗因子降低。然而，在所有情况下，损耗因子的变化都没有表现出作为磁场函数的可预测趋势。为了研究用于控制半主动系统阻尼的基于磁流变的解决方案，内部制作了磁流变流体弹性体样品。这些样品使用三种不同的铁浓度制造，并在压缩（挤压）模式下进行测试。这些实验的结果证实，材料的等效阻尼系数随着磁场的增加而增加，随着磁流变流体中铁浓度的增加，这种影响变得更强。还证明了磁流变效应高度依赖于加载频率和振幅，其中等效阻尼系数随着加载频率和振幅的增加而减小。在上述所有情况下，磁流变流体弹性体的刚度表现出微小的变化，这提供了内部开发的磁流变流体弹性体作为仅阻尼控制选项，这一发展与报告中报道的磁流变流体弹性体不同。文学。其中等效阻尼系数随着加载频率和幅值的增加而减小。在上述所有情况下，磁流变流体弹性体的刚度表现出微小的变化，这提供了内部开发的磁流变流体弹性体作为仅阻尼控制选项，这一发展与报告中报道的磁流变流体弹性体不同。文学。其中等效阻尼系数随着加载频率和幅值的增加而减小。在上述所有情况下，磁流变流体弹性体的刚度表现出微小的变化，这提供了内部开发的磁流变流体弹性体作为仅阻尼控制选项，这一发展与报告中报道的磁流变流体弹性体不同。文学。