考虑边界滑移和惯性效应的磁流变液缓冲器特性分析

摘要

In order to satisfy the adaptability of counterrecoil mechanism of cased telescoped ammunition gun to different ammunitions,a magneto-rheoligical fliud (MRF) damper based on multistage annular channel is proposed,which can satisfy the maximum recoil force and reduce the recoil displacement.The magnetic circuit of magneto-rheological energy absorbers (MREA) is analyzed by using the finite element method,and the relationship between the exciting current and the average magnetic induction intensity in the damping channel is obtained.The model parameters of MR fluid under non-and magnetic fields are identified based on the experimental data obtained by an Anton Paar rheometer.The flow differential equations of MR fluid in the buffering channel are established in considering the inertia effect and the boundary slip.The flow velocity distribution of MR fluid is obtained,and the relationship between piston speed and buffering force of damper is deduced.A MREA is fabricated based on the theoretical analysis above,and a drop hammer impact test bench is set up.Impact tests at different impact speeds are carried out,and the experimental data are compared with the theoretically analyzed results.Results show that the velocity distribution characteristics of magnetorheological fluid are similar under the conditions of different inertia effects and slippage boundary,but the peak value of velocity varies.When the boundary slippage coefficient is 0.000 1,the theoretical buffering force of MRF damper is close to the experimental value.Under the impact velocity of 1.55 m/s,the peak value of buffering force is increased by 15 000 N when the current increases from 0 A to 3 A.Under the impact velocity of 1.90 m/s,the peak value of buffering force is increased by 25 000 N when the current increases from 0 A to 4 A.%为满足某埋头弹火炮反后坐装置对不同弹种发射时的可调节适配性,并在满足最大后坐力的同时减小最大后坐位移,提出了一种基于多级环形通道的磁流变液缓冲器.利用有限元方法分析了缓冲器磁路,得出了阻尼通道平均磁感应强度与励磁电流的关系;利用安东帕流变仪测试数据,辨识了磁流变液在零磁场和磁场下的模型参数;建立阻尼通道中磁流变液的流动微分方程,在考虑惯性项和边界滑移条件下,得出了阻尼通道内磁流变液的流速分布特征,推导了缓冲器的阻尼力与活塞速度之间关系;根据理论研究结果,制作磁流变液缓冲器,构建了落锤冲击实验台,并进行不同冲击速度的冲击实验.研究表明:不同惯性效应和边界滑移条件下磁流变液流动速度分布规律相似,但流动速度峰值不同;边界滑移系数为0.000 1时磁流变液缓冲器的理论缓冲力与实验值接近;在冲击速度为1.55 m/s、电流从0A变化到3A时,缓冲力峰值增大了15 000 N;在冲击速度为1.90 m/s、电流从0A变化到4A时,缓冲力峰值增大了25 000 N.