基于磁场有限元分析的磁流变缓冲器结构设计

Design of a Magneto-rheological Damper Based on Magnetic Field FEM Analysis

基于磁场有限元分析和Bingham塑性流动模型,对某实验用火炮后坐磁流变缓冲器进行了结构设计.建立了磁流变缓冲器的二维轴对称磁场有限元模型,分析了活塞长度、线圈内直径以及油缸壁厚等参数的变化对间隙中MR流体的磁通密度的影响,确定了一个可以使间隙中MR流体磁通密度达到最大的结构尺寸方案.使用Bingham模型,计算了不同应用电流下磁流变缓冲器的阻尼力-速度关系.进行了火炮后坐动力学计算,计算结果表明,有限元法给出了比解析法更准确的磁场强度解,所设计的磁流变缓冲器满足火炮发射要求.

A structural optimal design methodology of a magneto-rheological （MR） damper for gun recoil application was presented based on electro-magnetic finite element analysis and Bingham plastic flow model. The 2D axisymmetric finite element model was created. The magnetorheological valve was analyzed. The influences of the structure parameters （core length, coil diameter, and oil cylinder wall thickness, etc） on the flux density of MR fluid in flow duct were analyzed, and the optimal structural parameters were determined so as to obtain the maximal damping force with the minimal outline size. The relationship curve of damping force with velocity was calculated by using Bingham plastic model, and the recoil dynamics for a 25 mm gun was simulated. The numerical results indicate that a more accurate solution for magnetic strength of magneto-rheological damper can be obtained by FEM than by analytic method. The design parameters of this MR damper can satisfy the gun firing requirement.