起落架缓冲器卡滞动态临界摩擦探究

Dynamic critical friction of landing gear shock absorber binding

为了探究起落架缓冲器卡滞特性设计准则,以某无人机主起落架为研究对象,依据飞机设计手册第14册中缓冲器卡滞特性分析方法,进行了静态和动态临界摩擦分析.分析表明动态临界摩擦在偏航着陆工况和机尾下沉回弹工况下可能发生卡滞.进而结合起落架落震动力响应曲线分析了动态临界摩擦的物理意义,发现现有飞机设计手册第14册中的动态临界摩擦分析方法卡滞判据并不成立,不应在计算临界摩擦系数时计入油液阻尼力.对于起落架缓冲器某状态时刻的卡滞特性分析,以飞机设计手册第14册中静态临界摩擦进行校核更为准确.

In order to explore the design criterion of landing gear shock absorber binding,based on the method in aircraft design manual,takeoff and landing system design,the static and dynamic critical friction coefficients of a certain unmanned aerial vehicle＇s main landing gear were analyzed. The analysis shows that the dynamic critical friction in yaw landing load condition and maximal spring back drag in tail sinking load condition are prone to bind. And then combined with the landing gear drop dynamic response curve,the physical meaning of shock absorber dynamic binding was studied. Research shows that the argument foundation of the dynamic critical friction analysis does not hold and oleo-damping force should not be included when calculating the critical friction coefficient. For the analysis of landing gear shock absorber binding in the state of a moment,it is more accurate that taking the method of static critical friction in aircraft design manual-takeoff and landing system design to check.