Abstract The effects of iron particle volume fraction (PVF) on the dynamic compression mode properties of isotropic and anisotropic magnetorheological elastomers (MREs) are experimentally investigated considering wide ranges of excitation frequency (1 Hz to 30 Hz), strain amplitude (2.5% to 20%) and magnetic flux density (0 to 750 mT). MRE samples with three different PVFs (15%, 30% and 45%) were fabricated in the laboratory and a test rig was designed to measure their magneto-mechanical characteristics. The effect of PVF on the loss modulus, denoted as PVF-dampening was substantially higher compared to that on the elastic modulus, denoted as PVF-stiffening. Moreover, PVF effects on compression mode properties of the isotropic MRE were greater compared to the anisotropic MRE, and showed coupled dependence on the excitation and magnetic field conditions. Results revealed that strain-rate stiffening of isotropic MRE increased with increasing PVF while slightly decreased for anisotropic MRE. Besides, strain-softening of both MREs increased with increasing PVF. Results were also suggesting of strong dependence of MR effect on the loading conditions, apart from the PVF. MR effect in view of elastic and loss moduli for isotropic MRE increased with increasing PVF from 15% to 45% at 1 Hz, but at higher frequency they become maximum around 30% PVF, regardless of strain amplitude. Both MR effects for anisotropic MRE, however, become minimum around 30% PVF, irrespective of frequency and strain amplitude. Owing to the observed coupled effects of the loading factors with the PVF, a simple phenomenological model was formulated considering independent functions in PVF, excitation frequency, strain amplitude and magnetic flux density for predicting compression elastic and loss moduli of both MREs. The proposed model required identifications of only six unknown constants, showed reasonably good agreements with the measured data.

中文翻译：

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铁颗粒体积分数对磁流变弹性体压缩模态特性的影响

摘要 考虑到宽范围的激励频率（1 Hz 至 30 Hz）、应变幅度（2.5% 至 20 %) 和磁通密度（0 到 750 mT）。在实验室中制造了具有三种不同 PVF（15%、30% 和 45%）的 MRE 样品，并设计了一个测试台来测量它们的磁机械特性。PVF 对损耗模量（表示为 PVF 阻尼）的影响与对弹性模量（表示为 PVF 硬化）的影响相比要高得多。此外，与各向异性 MRE 相比，PVF 对各向同性 MRE 的压缩模式特性的影响更大，并显示出对激发和磁场条件的耦合依赖性。结果表明，各向同性 MRE 的应变率硬化随着 PVF 的增加而增加，而各向异性 MRE 的应变率刚度略有下降。此外，两种 MRE 的应变软化都随着 PVF 的增加而增加。结果还表明，除 PVF 外，MR 效应对加载条件有很强的依赖性。考虑到各向同性 MRE 的弹性和损耗模量，MR 效应随着 PVF 在 1 Hz 下从 15% 增加到 45% 而增加，但在较高频率下，它们在 30% PVF 附近达到最大值，而与应变幅度无关。然而，无论频率和应变幅度如何，各向异性 MRE 的两种 MR 效应在 30% PVF 左右变得最小。由于观察到负载因子与 PVF 的耦合效应，考虑到 PVF、激励频率、应变幅度和磁通密度中的独立函数，制定了一个简单的现象学模型，用于预测两种 MRE 的压缩弹性和损耗模量。所提出的模型只需要识别六个未知常数，显示出与测量数据相当好的一致性。