舰载机弹射起飞过程中,由于牵制载荷突卸而产生的前起落架沿航向的快速振动会给机体结构和设备都带来严重的疲劳问题,为研究该振动现象并提出解决方案,建立了舰载机弹射起飞动力学模型,分析计算了前起落架的受载情况,并详细论述其动力学成因,推导了消除前起落架振动现象的充分必要条件。研究结果表明:牵制载荷沿下扭力臂轴向的载荷分量所造成的缓冲器活塞杆的向后弯曲是导致牵制载荷突卸后前起落架振动的主要原因;牵制载荷突卸后,起落架的前后振动导致起落架与机身铰接处的载荷快速、大幅的振荡,对机体结构以及机载设备的寿命和使用安全都会产生不利影响;牵制杆的长度直接影响牵制载荷沿下扭力臂轴向的载荷分量,降低该载荷分量可以有效地解决前起落架由于牵制载荷突卸所带来的振动问题。
The vibration of a nose landing gear caused by the sudden discharge of holdback load during the catapult launch of a carrier-based aircraft could bring serious fatigue both to the structure of the launch and the airborne equipment. To investigate the vibration and seek a solution, a dynamic model of the catapult launch is established. The load of the nose landing gear is calculated, while the kinetics and the way to deal with the phenomenon is also discussed in detail. From the catapult launch calculation, three important conclusions are obtained: during the tension stage, there is a long stroke and aft bending of the nose landing gear; once the holdback load suddenly discharges, the landing gear strut extends and springs forward rapidly; the fore-aft vibration of the nose landing gear produces a rapid and drastic load change at the joint of the gear and the fuselage. This vibration load has an adverse effect on the life and safety of the structure and the equipment of the aircraft. The length of the holdback bar influences the load along the lower torque link directly, and reducing this load has an obvious effect on the reduction of the vibration after a sudden discharge of the holdback load.
[1] Lucas C B. Catapult criteria for a carrier-based aircraft. AD702814, 1968.
[2] Ramsey J E, Dixon W R. Carrier suitability tests of the model A-6A aircraft. Naval Air Test Center, 1967.
[3] 郑本武. 舰载飞机弹射起飞性能和影响因素分析[J]. 飞行力学, 1992, 10(3): 27-33. Zheng Benwu. The catapulting performance of the carrier based aircraft and the parameter study[J]. Flight Dyna-mics, 1992, 10(3): 27-33. (in Chinese)
[4] 郑本武. 前起落架突伸对舰载飞机弹射起飞航迹的影响[J]. 南京航空航天大学学报, 1994, 26(1): 27-33. Zheng Benwu. The influence of the nose gear fast-extension on the catapult trajectory for carrier-based airplane[J]. Transactions of Nanjing University of Aeronautics & Astronautics, 1994, 26(1): 27-33. (in Chinese)
[5] 金长江, 洪冠新. 舰载机弹射起飞及拦阻着舰动力学问题[J]. 航空学报, 1990, 11(12): 534-542. Jin Changjiang, Hong Guanxin. Dynamic problems of carrier-aircraft catapult launching and arrest landing [J]. Acta Aeronautica et Astronautica Sinica, 1990, 11(12): 534-542. (in Chinese)
[6] Wang W J, Qu X J, Guo L L. Multi-agent based hierarchy simulation models of carrier-based aircraft catapult launch[J]. Chinese Journal of Aeronautics, 2008, 21(3): 223-231.
[7] 胡淑玲, 林国锋. 前起落架突伸对舰载机起飞特性的影响[J]. 飞行力学, 1993, 12(1): 28-34. Hu Shuling, Lin Guofeng. The effects of nose landing gear jump on the carrier aircraft catapult take-off flight path[J]. Flight Dynamics, 1993, 12(1): 28-34. (in Chinese)
[8] 沈强, 黄再兴. 舰载机前起落架突伸性能优化[J]. 计算机辅助工程, 2009, 18(3): 31-36. Shen Qiang, Huang Zaixing. Optimization of fast-extension performance of nose landing gear of carrier-based aircraft[J]. Computer Aided Engineering, 2009, 18(3): 31-36. (in Chinese)
[9] 黄再兴, 樊蔚勋, 高泽迥. 舰载机前起落架突伸的动力学分析[J]. 南京航空航天大学学报, 1995, 27(4): 466-473. Huang Zaixing, Fan Weixun, Gao Zejiong. Dynamical analysis of nose gear fast-extension of carrier based aircraft[J]. Transactions of Nanjing University of Aeronautics & Astronautics, 1995, 27(4): 466-473. (in Chinese)
[10] 沈强, 黄再兴. 舰载机起落架突伸性能参数敏感性分析[J]. 航空学报, 2010, 31(3): 532-537. Shen Qiang, Huang Zaixing. Sensitivity analysis of fast-extension performance of carrier based aircraft landing gear to varying parameters[J]. Acta Aeronautica et Astronautica Sinica, 2010, 31(3): 532-537. (in Chinese)
[11] 王俊彦, 吴文海, 高丽, 等. 舰载机弹射起飞建模与控制[J]. 飞行设计, 2010, 30(2): 10-13. Wang Junyan, Wu Wenhai, Gao Li, et al. Modeling and control of carrier-aircraft during catapult launch[J]. Aircraft Design, 2010, 30(2): 10-13. (in Chinese)
[12] Skorupa J A. System simulation in aircraft landing gear and tire development. Air Force Institute of Techno-logy Wright Patterson Air Force Base Ohio School of Engineering, 1976: 35-37.
[13] Flügge W, Coale C W. The influence of wheel spin-up on landing gear impact. Stanford University, 1954: 1-18.
[14] Smiley R F, Horne W B. Mechanical properties of pneumatic tires with special reference to modern aircraft tires. NASA-TN-4110, 1958: 37-39.
[15] 《飞机设计手册》总编委会. 飞机设计手册: 起飞着陆系统设计[M]. 北京: 航空工业出版社, 2002: 56-59. Handbook of Aircraft Design Editorial Committee. Aircraft design manual: takeoff and landing system design [M]. Beijing: Aviation Industry Press, 2002: 56-59. (in Chinese)
CJA