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%。
The dynamics of nose landing gear shimmy is studied in this paper with a certain type of aircraft. Based on the multi-body dynamics theory,a dynamics model of shimmy is developed which takes into consideration the flexibility of nose landing gear and airframe by means of the component mode synthesis method,to investigate the stability of shimmy. The model is verified with the data of static tests and mode tests. Diagrams of the stable region are presented accordingly,formed by the taxiing speed and critical anti-shimmy damping coefficients,to explore the influence of the movement and flexibility of the airframe. The result shows that,the initial angle of nose wheel contributes little to shimmy analysis. A simplified method,which replaces the flexibility of the nose landing gear by the connection stiffness between the nose landing gear and airframe,is not accurate enough and can only be applied to qualitative analysis. The movement of the rigid airframe exerts little influences on the critical damping coefficient. However,the flexibility of the airframe has considerable influence and it may increase the critical damping coefficient by 12.1% on the average at mid and high speeds.
[1] Pritchard J. An overview of landing gear dynamics. NASA/TM-1999-209143, 1999.
[2] Stefania G, Marco M, Gian L G. Anti-skid induced aircraft landing gear instability[J]. Aerospace Science and Technology, 2008, 12(8): 627-637.
[3] 诸德培. 摆振理论及防摆措施[M]. 北京: 国防工业出版社, 1984: 2-4, 20-24. Zhu Depei. Shimmy theory and anti-shimmy measure[M]. Beijing: National Defense Industry Press, 1984: 2-4, 20-24. (in Chinese)
[4] 王学军, 乔新. 前轮非线性摆振稳定性分析[J]. 南京航空航天大学学报, 1992, 24(1): 9-18. Wang Xuejun, Qiao Xin. The stability analysis of the nonlinear shimmy[J]. Journal of Nanjing Aeronautical Institute, 1992, 24(1): 9-18. (in Chinese)
[5] Gerhard S. Shimmy analysis of a simple aircraft nose landing gear model using different mathematical methods[J]. Aerospace Science and Technology, 1997, 8(1): 545-555.
[6] Fong A, Eng P. Shimmy analysis of a landing gear system//ADAMS International User Conference. 1995.
[7] Chris H. Preliminary nose landing gear shimmy using MSC.ADAMS aircraft//MSC.ADAMS North American User Conference. 2002.
[8] 张明, 聂宏, 朱如鹏, 等. 基于虚拟样机技术的飞机地面运动多学科协同仿真[J]. 中国机械工程, 2010, 21(10): 1194-1199. Zhang Ming, Nie Hong, Zhu Rupeng, et al. Multi-disciplinary collaborative simulation of aircraft ground maneuvers based on virtual prototype technology[J]. China Mechanical Engineering, 2010, 21(10): 1194-1199. (in Chinese)
[9] 王学军. 飞机前轮摆振稳定性分析. 南京: 南京航空航天大学航空宇航学院, 1991. Wang Xuejun. The stability analysis of aircraft landing gear shimmy. Nanjing: College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, 1991. (in Chinese)
[10] 万晓峰. LMS Virtual.Lab Motion入门与提高[M]. 西安: 西北工业大学出版社, 2010: 33. Wan Xiaofeng. LMS Virtual.Lab Motion approach and enhance[M]. Xi'an: Northwestern Polytechnical University Press, 2010: 33. (in Chinese)
[11] 周福亮. 飞机起落架摆振稳定性仿真分析研究. 南京: 南京航空航天大学航空宇航学院, 2008. Zhou Fuliang. Study on the shimmy stability of aircraft landing gear. Nanjing: College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, 2008. (in Chinese)
[12] Johnson K L. Contact mechanics[M]. Cambridge: Cambridge University Press, 1985.
[13] 飞机设计手册总编委会. 飞机设计手册14: 起飞着陆系统设计[M]. 北京: 航空工业出版社, 2002: 95-102. Committee of Aircraft Design Manual. Aircraft design manual Book 14: taking-off and landing devices design [M]. Beijing: Aviation Industry Press, 2002: 95-102. (in Chinese)
[14] Smiley B F, Horne W B. Mechanical properties of pneumatic tires with special reference to modern aircraft tires. Horne NACA-TN-4110, 1958.
[15] 国防科学技术工业委员会. GJB 5097—2002. 飞机前起落架防摆设计要求[S]. 2002. The Commission of Science, Technology and Industry for National Defense. GJB 5097—2002. Design requirement of anti-shimmy for nose landing gear of aircraft[S]. 2002. (in Chinese)
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