This study investigates dynamic mechanical properties and creep and recovery behaviors of disc-shaped magnetic Fe₃O₄ nanoparticles with carbonyl iron (CI) flake-shaped microparticles in water-based MR fluid. The experimental study is performed using a parallel plate rheometer. Dynamic performance and creep and recovery behaviors help understand deformation mechanism for its practical applications in MR devices like seismic vibration control, active dampers, earthquake dampers, etc., under applied strain, and stress levels. The oscillatory experiment reveals a transition from viscoelastic-to-viscous behavior at the critical strain of 0.1%. The storage modulus $\left(G^{\prime }\right)$ of CI/Fe₃O₄ MR fluid showed a stable plateau region over the small strain area and storage modulus $\left(G^{\prime }\right)$ independent of strain amplitude. The frequency experiment demonstrated that storage moduli $\left(G^{\prime }\right)$ exhibit elastic response and stable plateau region over the complete external frequency range, suggesting the distinguished solid-like behavior of the MR fluid. Creep and recovery experiments showed that fluid acts as a linear viscoelastic material at lower stress levels. As the stress levels increase, the contribution of retardation strain and viscous strain decreases, and it acts like nonlinear viscoelastic material. In summary, this work is expected to obtain MR fluid results for application in MR devices under applied strain, frequencies, and constant stress levels.

本研究调查了圆盘状磁性 Fe ₃ O ₄纳米粒子与羰基铁 (CI) 片状微粒在水基 MR 流体中的动态力学性能以及蠕变和恢复行为。使用平行板流变仪进行实验研究。动态性能和蠕变和恢复行为有助于理解变形机制，以帮助了解其在 MR 设备（如地震振动控制、主动阻尼器、地震阻尼器等）中在施加应变和应力水平下的实际应用。振荡实验揭示了在 0.1% 的临界应变下从粘弹性到粘性行为的转变。储能模量$\left(G^{\prime }\right)$CI/Fe ₃ O ₄ MR 流体在小应变区域和储能模量上显示出稳定的平台区域$\left(G^{\prime }\right)$与应变幅度无关。频率实验表明，储能模量$\left(G^{\prime }\right)$在整个外部频率范围内表现出弹性响应和稳定的平台区域，表明 MR 流体具有显着的类似固体的行为。蠕变和恢复实验表明，流体在较低应力水平下充当线性粘弹性材料。随着应力水平的增加，延迟应变和粘性应变的贡献减小，它的作用类似于非线性粘弹性材料。总之，这项工作有望在施加应变、频率和恒定应力水平下获得用于 MR 设备的 MR 流体结果。