【作者】 陈雷；

【导师】 聂宏；

【作者基本信息】 南京航空航天大学 ， 飞行器设计， 2007， 硕士

【摘要】 起落架是飞机的重要部件,对其性能的正确计算是飞机着陆安全的重要保证。通常在计算起落架缓冲性能时将机身视为刚体,忽略了弹性的影响,这样必然造成误差。本文的研究工作就是分析机身弹性对起落架着陆性能的影响。本文中建立了弹性飞机的着陆模型。其中机身的动力学模型根据拉格朗日方程和虚功原理建立,作用于机身的广义力除起落架垂直支承力和飞机升力外还考虑了起落架作用于机身的弯矩。推导了起落架在起转、回弹阶段的动力学方程以及各分力的计算方法。为了便于对起落架着陆性能进行数值计算,利用经典“龙格-库塔”法对方程组进行了标准化。在已经建立的模型基础上,开发了考虑机身弹性的起落架着陆性能分析软件。该软件可以计算在给定着陆条件、前五阶对称模态参数、缓冲器性能、轮胎参数等条件下起落架的着陆响应并可以进行简单的运动仿真,可以作为计算机身弹性对起落架着陆性能影响的有效工具。利用上述软件计分别计算了不同模态广义质量,安装点广义位移和模态振动频率下的起落架着陆响应。算例结果表明飞机的起落架设计有必要考虑机体结构弹性,并从全局出发,采用特殊的构造措施和优化设计技术。更多还原

【Abstract】 Landing-gear is an important component of the airplane, and the calculation of its performance ensures safe landing. In the conventional design of landing-gears, the airplane is usually assumed as a rigid body. The neglect of airplane flexibility leads to numerical error. In this paper, the effect of airplane flexibility on the landing-gear behavior is discussed.Flexible airplane landing model is established. The dynamic model of the fuselage is established by the application of Lagrange’s equation and virtual-work principles. The generalized force on the fuselage includes not only vertical force of the landing-gear and airplane lift, but also the landing-gear moment on the airplane. The dynamic equations and calculation of the forces are presented. The R-K method is used to generalize the equations for numerical calculation of the landing-gear behavior.Based on the model, a software for calculation analysis of landing-gear considering airplane flexibility is developed. The software is an effectual tool for evaluating the performance of landing-gear primarily. It can be used for the calculation of the response of the landing-gear when initial landing condition, feature of the first 5th symmetrical modes, shock-strut performance and tire parameters are given. Landing simulation is also presented by the software.A series of landing-gear responses are calculated by given different generalized mass, the frequency of the modes and the translation of the modes in the station of landing-gear. From an overall point of view, airplane flexibility must be considered and optimization design must be used in landing-gear design of a flexible airplane.更多还原