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以某型客机为对象,研究了飞机滑跑时前起落架的摆振动力学问题。基于多体动力学理论,采用子结构模态综合法将关键部件柔性化,建立了计及前起落架和机身弹性的全机地面滑跑刚柔耦合动力学模型,并进行了摆振稳定性仿真分析。采用起落架静力试验和模态试验的结果对模型进行校验,仿真结果与试验结果吻合较好。给出了以飞机速度和防摆阻尼系数组成的飞机摆振稳定区域图,研究了机身刚体运动与弹性对摆振的影响。结果表明:采用线性防摆阻尼时,定义摆振临界稳定所需的初始摆角对临界防摆阻尼的影响可忽略不计;采用简化方法将起落架弹性等效为起落架和机身连接刚度的方法会带来较大的误差,仅适用于定性分析;机身刚体运动对防摆阻尼影响很小,机身柔性的影响相对较大,使得中高速情况下所需防摆阻尼平均增加了12.1%。
Taking a passenger aircraft as an example, this paper studies the pendulum vibration dynamics of the nose landing gear when the aircraft slips. Based on the multi-body dynamics theory, the substructure modal synthesis method is used to flexibly the key components, and a rigid-flexible coupled dynamics model of the whole ground slip considering the nose gear and the fuselage elasticity is established. Sexual simulation analysis. The results of static test and modal test of landing gear verify the model, and the simulation results are in good agreement with the test results. The plane stability map of the aircraft, which is composed of the aircraft speed and the damping coefficient of the anti-roll, is given. The influence of rigid body motion and elasticity on the shimmy is studied. The results show that the initial swing angle required to define the critical stability of the shimmy vibration is negligible when the linear anti-roll damping is adopted. The simplified method is equivalent to the equivalent of the landing gear elasticity as the connection stiffness between the landing gear and the fuselage The method will bring greater error and is only suitable for qualitative analysis. The rigid body movement has little effect on the anti-roll damping, and the impact on the body flexibility is relatively large, making the required anti-rolling damping increased by an average of 12.1 %.