行程敏感式液阻减振器动力学特性的三维流-固耦合有限元仿真分析

3D FSI FEA SIMULATION AND ANALYSES OF THE DYNAMIC CHARACTERISTICS OF A DISPLACEMENT-SENSITIVE LIQUID DAMPER

建立了缸壁槽形行程敏感式减振器较精细的三维流-固耦合动力学仿真分析模型,利用基于ALE流-固耦合、滑移网格流-流耦合的同步化迭代流-固耦合计算方法及动网格控制方法求解减振器内部的稳态及瞬态流-固耦合动力学响应,进行了部分实验验证。量化分析了缸壁槽形行程敏感式减振器的高速阻尼特性、冲击阻尼特性和活塞偏置、缸壁槽通流面积及结构变化对阻尼特性的影响,结果表明:活塞沿压缩行程方向偏置后的阻尼特性是有利的,而沿伸张行程方向偏置的状态是不利的;缸壁槽的附加泄流作用可削减减振器在地面冲击激励下阻尼力的瞬间冲击峰值;多缸壁槽形行程敏感式减振器的阻尼特性表现出单条缸壁槽作用结果的叠加效应;缸壁槽对阻尼力的减弱比例随活塞速度幅值的减小而增大;缸壁槽在高速工况下被开启及关闭的瞬态过程中伴随有阻尼力波动现象,可通过适当延长缸壁槽端部收缩段加以改善。这些分析结论对于此类液阻减振器的变阻尼特性匹配设计具有重要的价值。

A three-dimensional fluid-structure interaction(FSI)model with arbitrary Lagrangian-Eulerian(ALE)liquid-structure coupling and sliding-mesh fluid-fluid coupling of a displacement-sensitive(DS)liquid damper with cylinder-wall grooves was constructed.The synchronous-iterative FSI method combined with the moving mesh control method was utilized to calculate the dynamic responses of the damper system under dynamic excitations.The results were partially verified by experiments.Several important problems were analyzed,including the damping characteristics under a high-speed and shock input,effects of the piston’s initial position offset and the grooves’structural variation on the damping characteristics.The results show that the offset of the piston’s initial position along the direction of the compression stroke was favorable,but the initial piston offset along the direction of the extension stroke was unfavorable.The damper with cylinder-wall grooves could reduce the instantaneous peak of damping force under a shock condition.The damping characteristics of the damper with multi-grooves showed to be an approximate superposition of the effect of each groove.The damping ratio was increased when the piston velocity amplitude decreased.The damping force fluctuation occurred when the groove paths were opened and closed under higher speed conditions,but it could be improved by extending the end section.These results are helpful for the design of the passive controlled damping characteristics of this kind of liquid dampers.