永磁式电磁阻尼器磁性能解析计算及阻尼特性分析

Halbach永磁阵列作为一种新型的永磁体排列形式,以其优异的磁场利用率和自屏蔽性能逐渐受到广泛关注,以该永磁阵列为结构基础的电磁阻尼器相较于其他的结构形式表现出更好地磁场性能。以Halbach永磁阵列电磁阻尼器为研究对象,分析它的阻尼特性。首先根据阻尼器的结构形式建立了相应的数学分析模型,并利用分层理论对其进行了解析推导,同时建立有限元模型,并进行了互相印证。计算结果表明,初级与次级相对速度到达临界速度值时电磁阻尼力最大,若相对速度继续增大电磁阻尼力反而减小。通过引入火炮后坐运动方程,分析强冲击载荷下电磁阻尼器的电磁阻尼力、后坐速度和后坐位移规律,确保在后坐过程中后坐速度不超过临界速度。通过有限元法研究了不同气隙宽度和内筒厚度对电磁阻尼力的影响,结果表明电磁阻尼力随着气隙宽度的增大而减小,内筒厚度过大会导致电磁阻尼力曲线呈现出“马鞍”型。合理地选择结构参数能够避免退磁现象,确保所设计的电磁阻尼器能够满足使用要求,为电磁阻尼器的设计提供了参考。

Analytical Calculation of Magnetic Performance and Damping CharacteristicAnalysis of Permanent Magnet Electromagnetic Damper

As a new type of permanent magnet arrangement,the Halbach permanent magnet array has gradually attracted wide attention for its excellent magnetic field utilization and self-shielding performance. Compared with other structural forms,the electromagnetic damper based on the Halbach permanent magnet array exhibits better magnetic field performance. Taking the Halbach permanent magnet array electromagnetic damper as the research object,its damping characteristics were analyzed. Firstly,the corresponding mathematical analysis model was established according to the structural form of the damper,and it was deduced analytically by using the layered theory. The finite element model was established to verify the analytical model. The calculation results show that the electromagnetic damping force is the largest when the relative velocity of the primary and secondary reaches the critical velocity value,and the electromagnetic damping force decreases if the relative velocity continues to increase. By introducing the artillery recoil motion equation,the damping force,recoil velocity and recoil displacement law of the electromagnetic damper under intensive impact load were analyzed to ensure that the recoil velocity does not exceed the critical velocity during the recoil process. The effects of different air gap widths and conductor cylinder thicknesses on the damping force were analyzed by the finite element method. The result shows that the electromagnetic damping force decreases with the increase of the air gap width; the electromagnetic damping force curve presents a“saddle”shape if the thickness of the conductor is too large. Reasonable selection of structural parameters can avoid demagnetization,and ensure that the designed electromagnetic damper can meet the requirements of use,which provides a reference for the design of electromagnetic dampers.