带梯形截面导磁环的全通道有效车用磁流变减振器设计

车用磁流变减振器(MRD)往往结构尺寸较小，且传统的车用MRD阻尼通道有效工作长度较短，输出阻尼力小，导致其工程应用受到限制。针对这一问题，提出一种带梯形截面导磁环的新型全通道有效MRD以增大阻尼通道有效工作长度，减缓磁饱和，并基于磁流变液流变特性和流体动力学理论给出了具体的结构与磁路设计计算方法，将5种不同结构的MRD进行有限元仿真对比。通过阻尼特性测试试验，分析其阻尼特性并与普通MRD、带弯曲磁路全通道有效MRD进行对比，应用线性二次高斯(LQG)控制器进行减振性能分析。研究结果表明：新型全通道有效MRD能够显著提高阻尼通道有效工作长度，达到阻尼通道全长的99%以上；新型全通道有效MRD能改善小尺寸MRD易发生磁饱和的问题；在相同电流激励与尺寸约束下阻尼通道的磁场强度分布更均匀，平均磁场强度更大，具有更大的输出阻尼力；新型全通道有效MRD在结构尺寸小的同时具有更大的输出阻尼力；新型全通道有效MRD相对于普通MRD具有更好的减振性能，能够进一步降低车辆的簧上质量加速度与轮胎动变形21.51%和1.43%。该研究能有效扩宽小尺寸MRD的实际应用范围，具有一定的工程应用价值。

Design of a Full-Length Effective Automotive Magnetorheological Damper with magnetically Conductive Ring of Trapezoidal Cross Section

Magnetorheological dampers (MRD) used in automobiles are usually of small size, and the traditional MRD damping channel features short effective working length and small output damping force, which results in its limited engineering application. To solve this problem, a novel full-length effective MRD with magnetically conductive ring of trapezoidal cross section was proposed to increase the effective working length of the damping channel and slow down magnetic saturation. Based on the rheological properties of magnetorheological fluid and fluid dynamics theory, the design and calculation method of specific structure and magnetic circuit were given. Five MRDs with different structures were compared by finite element simulation. The results showed that: the proposed novel full-channel effective MRD can significantly increase the effective working length of the damping channel, reaching over 99% of the full length; it can also improve the magnetic saturation problem for a small-size MRD; in addition, under the same current excitation and size constraint, the magnetic field intensity distribution of the damping channel is more uniform, the average magnetic field intensity is larger, and the output damping force is larger; the damping characteristics of the new MRD were analyzed and compared with those of the common MRD and the full-length effective MRD with bending magnetic circuit, indicating that the new full-length effective MRD has a larger output damping force while the structure size is smaller. Finally, the LQG controller was used to analyze the vibration reduction performance, showing that the new full-length effective MRD has better vibration reduction performance than the common MRD, and can further reduce the sprung mass acceleration and tire dynamic deformation by 21.51% and 1.43%. This study can effectively expand the practical application range of small-size MRDs and has certain engineering application significance.