Magnetorheological (MR) damper is one of the most promising smart devices for dissipating seismic energy and reducing structural vibrations. The MR dampers with multiple coils are widely adopted to enhance the output damping forces and seismic performance. In order to study the dynamic characteristics of multicoil MR dampers from a micro to macro viewpoint, a three-coil MR damper was designed and manufactured in this paper. The performance tests of the three-coil MR damper under different excitation currents, displacement amplitudes, frequencies, and coil combinations were conducted. Assuming that the distance between two adjacent ferromagnetic particles meets chi-square distribution, the two-column micromodel for the MR fluid was modified by introducing a distribution parameter. The modified MR fluid micromodel was verified by comparing the damping forces calculated by this model with experimental data. Combining the modified micromodel for the MR fluid and the double-sigmoid model for MR dampers, a mathematical model for the three-coil MR damper was proposed. The microstructure-based sigmoid model considers the effects of yield shear stress of the MR fluid and internal magnetic induction intensity on the damping force. The comparison of the proposed model and the performance test data shows that the microstructure-based sigmoid model can finely describe the dynamic characteristics and magnetic saturation properties of the three-coil MR damper under different excitation currents and loading conditions, which provides a good basis for control strategies and dynamic analysis of structures with multicoil MR dampers.

中文翻译：

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三线圈磁流变阻尼器的性能测试和基于微结构的 Sigmoid 模型

磁流变（MR）阻尼器是最有前途的用于耗散地震能量和减少结构振动的智能设备之一。多线圈MR阻尼器被广泛采用，以提高输出阻尼力和抗震性能。为了从微观到宏观的角度研究多线圈磁流变阻尼器的动态特性，本文设计并制造了一种三线圈磁流变阻尼器。对三线圈磁流变阻尼器在不同励磁电流、位移幅值、频率和线圈组合下的性能进行了测试。假设两个相邻铁磁粒子之间的距离满足卡方分布，通过引入分布参数来修改MR流体的两柱微模型。通过将该模型计算的阻尼力与实验数据进行比较，验证了改进的 MR 流体微模型。结合改进后的磁流变微模型和磁流变阻尼器的双S形模型，提出了三线圈磁流变阻尼器的数学模型。基于微结构的 sigmoid 模型考虑了 MR 流体的屈服剪切应力和内部磁感应强度对阻尼力的影响。所提模型与性能测试数据对比表明，基于微结构的sigmoid模型可以很好地描述不同励磁电流和加载条件下三线圈磁流变阻尼器的动态特性和磁饱和特性，为研究提供了良好的基础。多线圈磁流变阻尼器结构的控制策略和动力学分析。