油孔几何参数对起落架落震动力学的影响研究

摘要

油液阻尼性能是影响起落架缓冲性能关键因素,而流量系数则决定着缓冲阻尼力的大小.针对目前起落架动力学分析中流量系数的估算方法计算精度问题,基于管道流体力学方法和缓冲器油孔结构建立了流量系数的理论模型.建立起落架落震动力学模型,采用数值分析法求解了模型的动力学特性,对比分析了长径比、孔径管径比、孔口倒角等油孔几何参数对于起落架缓冲阻尼力和轴向合力的影响.研究表明:长径比增加1倍会使得油液阻尼力最大值减少7.34%,孔径管径比每增加0.1会使得油液阻尼力减少70%,孔口倒角会导致油液阻尼力最大值减少18.72%.%Oleo-damping performance is a key factor affecting the landing gear buffer performance,while the flow discharge coefficient determines buffer damping force.For improving the calculation precision of discharge coefficient estimation method in aircraft design manual,a model for discharge coefficient is es-tablished based on pipeline fluid mechanics and damping orifice structure.Furthermore,the drop dynamic model of landing gear is established,and the dynamic characteristics of the model are solved by numerical analysis method.On this basis the influence of orifice geometry parameters on the hydraulic force and the shock absorber axial force are analyzed and compared.The study demonstrates that,if the aspect ratio is doubled,the maximum hydraulic force will decrease by 7.34%.Each increase of 0.1 orifice diameter to pipe diameter ratio will make the hydraulic force decrease by 70%.The maximum hydraulic force will de-crease by 18.72%,if the chamber is applied.