针对磁流变液阻尼器存在磁场利用率不高和磁流变液沉降导致控制特性劣化的问题,提出一种基于多级径向流动模式的磁流变脂阻尼器方案,将磁流变脂的多级径向流动分解为源流与汇流的对称组合,建立了磁流变脂径向流动的分析模型.利用磁流变脂微单元平衡得出了磁流变脂尊静态径向流动微分方程,采用磁流变脂双粘度本构模型和无滑动边界条件,导出了磁流变脂径向流动速度分布函数和径向压力梯度分布函数.绘制了磁流变脂在不同半径处流动速度分布图,得到了磁流变脂阻尼器的阻尼力计算方法.按照轨道车辆抗蛇行减振器的技术要求,设计制作了基于多级径向流动模式的磁流变脂阻尼器样机,利用J95-Ⅰ型油压减振器试验台对其示功特性进行了测试,结果表明在不同激励电流下的磁流变脂阻尼器理论示功特性与实验示功特性能较好吻合.%A magneto-rheological ( MR) grease damper based on a multi-stage radial flow mode was put forward aiming at low magnetic field utilization rate resulting from short channels and performance degradation resulting from MR fluid settlements. An analysis model was built by dividing symmetrically a damping channel into a radial source flow channel and a radial confluent flow one. Flow differential equation for a quasi-static radial flow was deduced with MR grease micro-element force equilibrium. Both radial flow velocity profile and radial pressure distribution were obtained by solving the flow differential equation using MR grease Bi-viscous constitutive model and no-slip boundary condition. Diagrams of MR grease radial flow velocity versus radius were plotted by means of the radial flow velocity profile. The damping force algorithms of a MR grease damper also were obtained by integration of radial pressure gradient with respect to radial coordinate. In order to validate the rationality of the analysis model, a MR grease damper based on multi-stage radial flow mode was designed and fabricated in accordance with technical requirements of a railway vehicle anti-hunting vibration isolation system. The tests on a J95-I shock absorber test-platform with sine wave excitation were accomplished under the condition of piston peak velocity 0. 025m/s, oscillation amplitude 25mm and coil electric current range of 0. 2 to 1.0 A with an increment of 0. 2 A. The test results revealed that the theoretical damping force vs. disk displacement diagrams are in good agreement with those of tests.
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