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为进一步研究磁流变液减振器阻尼特性,将磁流变液当作一种由刚性悬浮颗粒与液体载液构成的高浓度悬浮液,考察其表观滑移对磁流变液减振器阻尼特性的影响。在对被简化成平行平板模型的磁流变液减振器环形阻尼通道内的流场进行分析时,针对磁流变液在磁场作用下磁性颗粒重排而导致液体中刚性粒子等效粒径增加的现象,在理论分析中考虑了磁流变液的表观滑移边界条件,并将其引入到Herschel-Bulkley模型中,从而将环形阻尼通道中的流场划分为3个区域,即表观滑移区、屈服区与非屈服区,分别对3个区域的流变学特性进行分析,推出了减振器输出阻尼力计算公式,与同条件下不考虑表观滑移时的阻尼力进行了对比。设计了双线圈式环形阻尼通道与旁通小孔并联型电磁活塞头,磁路模型通过了有限元验证,同时根据中国产某轿车悬架参数要求设计并制造了磁流变液减振器样机,通过台架测试得到了圆润饱满的示功特性曲线。结果表明:表观滑移会降低减振器的阻尼系数,且在窄通道、低流速与高磁场条件下表观滑移对输出阻尼力的影响较明显;设计的旁通小孔和浮动活塞分别有良好的泄流与体积补偿作用;活塞峰值速率为0.3m·s~(-1)时的理论阻尼力与试验测试阻尼力之间的最大偏差只有180N,说明考虑了表观滑移的理论模拟结果与试验测试结果能较好地吻合。
In order to further study the damping characteristics of magnetorheological fluid damper, the MR fluid is used as a high-concentration suspension consisting of rigid suspended particles and liquid carrier fluid, and its apparent slip to the MR fluid damping Damping characteristics of the impact. In the analysis of the flow field in the ring-shaped damping channel of a MRF absorber simplified as a parallel plate model, the magnetic particles are rearranged under the action of a magnetic field to cause the equivalent particle size of the rigid particles in the liquid In the theoretical analysis, the apparent slip boundary conditions of MR fluid are considered and introduced into the Herschel-Bulkley model, and the flow field in the ring-shaped damping channel is divided into three regions, namely, View of slip region, yield region and non-yield region, respectively, the rheological properties of the three regions were analyzed, the damping output damping force formula was introduced, and under the same conditions without apparent slip damping force Made a contrast. The dual-coil ring-shaped damping channel and the bypassing small hole shunt-type electromagnetic piston head were designed. The magnetic circuit model passed the finite element verification. At the same time, the MR damper was designed and manufactured according to the requirements of a Chinese-made suspension. Mock-up, through the bench test has been rounded and full of performance curve. The results show that: the apparent slip will reduce the damping coefficient of the shock absorber, and the effect of apparent slip on the output damping force is obvious under the conditions of narrow channel, low flow rate and high magnetic field; the designed bypass small hole and floating piston Respectively. The maximum deviation between the theoretical damping force and the test damping force is only 180N when the piston peak velocity is 0.3m · s -1, which means that the apparent slip The theoretical simulation results and experimental test results can be well matched.