Shock absorber system dynamic model in model-based environment

Nafi Kulaksiz; Sevval Cip; Zeynep Gedikoglu; Muhsin Hancer

doi:10.53391/mmnsa.2022.01.005

Authors

Nafi Kulaksiz Department of Aeronautical Engineering, Necmettin Erbakan University, 42140 Konya, Turkey https://orcid.org/0000-0003-2448-2668
Sevval Cip Department of Aeronautical Engineering, Necmettin Erbakan University, 42140 Konya, Turkey https://orcid.org/0000-0002-8577-0922
Zeynep Gedikoglu Department of Aeronautical Engineering, Necmettin Erbakan University, 42140 Konya, Turkey https://orcid.org/0000-0002-1800-4443
Muhsin Hancer Department of Astronautical Engineering, Necmettin Erbakan University, 42140 Konya, Turkey https://orcid.org/0000-0001-9599-8747

DOI:

https://doi.org/10.53391/mmnsa.2022.01.005

Keywords:

Shock absorber, landing-touchdown performance, oleo-pneumatic and strut, aircraft landing loads

Abstract

This paper addresses the mathematical modelling of aircraft landing gear based on the shock absorber system’s dynamics and examination of results depending on different touchdown scenarios and design parameters. The proposed methodology relies on determining an analytical formulation of the shock absorber system’s equation of motion, modelling this formulation on the model-based environment (Matlab/Simulink), and integrating with an accurate aircraft nonlinear dynamic model to observe the performance of landing gear in different touchdown or impact velocities. A suitable landing performance depends on different parameters which are related to the shock absorber system’s working principle. There are three subsystems of the main system which are hydraulic, pneumatic, and tire systems. Subsystems create a different sort of forces and behaviors. The air in the pneumatic system is compressed by the impact effect so it behaves like a spring and creates pneumatic or air spring force so the most effective parameter in this structure is determined as initial air volume. Hydraulic oil in the receptacle of the hydraulic system flow in an orifice hole when impact occurs so it behaves as a damper and creates damping or hydraulic force. The same working principle is acceptable for the air in the tire. The relationship between tire and ground creates a friction force based on dynamic friction coefficient depending on aircraft dynamics. As a result of this study effect of the impact velocity and initial air volume parameters on the system are examined and determined by optimization according to maximum initial load limits of aircraft and displacement of strut and tire surface.

Downloads

Download data is not yet available.

References

Ding, Y.W., Wei, X.H., Nie, H. & Li, Y.P. Discharge coefficient calculation method of landing gear shock absorber and its influence on drop dynamics. Journal of Vibroengineering, 20(7), 2550-2562, (2018).

Wahi, M.K. Oleopneumatic shock strut dynamic analysis and its real-time simulation. Journal of Aircraft, 13(4), 303-308, (1976).

Daniels, J.N. A method for landing gear modeling and simulation with experimental validation. NASA Reports, (1996).

Karakoc, T.H. & Erdem, M. Oleopneumatic shock absorber real-time simulation and analysis of the different oil service levels. Japon Society of Mechanical Engineers Spring Annual Meeting, 103-107, (1996).

Oktay, T., Konar, M., Onay, M., Aydin, M., & Mohamed, M.A. Simultaneous small UAV and autopilot system design. Aircraft Engineering and Aerospace Technology, Emerald Group Publishing Limited, 88(6), 818-834, (2016).

Lomax, T.L. Structural loads analysis for commercial transport aircraft: theory and practice. American Institute of Aeronautics and Astronautics, (1996).

Gudmundsson, S. General aviation aircraft design: applied methods and procedures. Butterworth-Heinemann, (2013).

CS-VLA, E.A.S.A. Certification specifications for very light aeroplanes. Amendment, (2009).

FAA. Airworthiness standards, normal, utility, acrobatic and commuter category airplanes. Federal Aviation Regulations, Part 23.

Yue, S., Nie, H., Zhang, M., Huang, M., Zhu, H., & Xu, D. Dynamic analysis for vertical soft landing of reusable launch vehicle with landing strut flexibility. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 233(4), 1377-1396, (2019).

Dinc, A. & Gharbia, Y. Effects of spring and damper elements in aircraft landing gear dynamics. International Journal of Recent Technology and Engineering IJRTE, 8(5), 4265-4269, (2020).

Milwitzky, B. & Cook, F.E. Analysis of landing gear behavior. National Advisory Committee for Aeronautics Report 1154, (1953).

Li, Y., Jiang, J.Z., Sartor, P., Neild, S.A. & Wang, H. Including inerters in aircraft landing gear shock strut to improve the touch-down performance. Procedia Engineering, 199, 1689-1694, (2017).

Açin, S. Uçak fren balatalarında karbon fiber boyut ve şeklinin tribolojik özelliklere etkisi. Master Thesis, Kocaeli University, (2019).

Li, Y., Jiang, J.Z., Neild, S.A., & Wang, H. Optimal inerter-based shock-strut configurations for landing-gear touchdown performance. Journal of Aircraft, AIAA, 54(5), 1901-1909, (2017).

Wei, X.H., Liu, C.L., Song, X.C., Nie, H. & Shao, Y.Z. Drop dynamic analysis of half-axle flexible aircraft landing gear. Journal of Vibroengineering, JVE International Ltd., 16(1), 266-274, (2014).

Alroqi, A.A., Wang, W., & Zhao, Y. Aircraft tire temperature at touchdown with wheel prerotation. Journal of Aircraft, AIAA, 54(3), 926-938, (2017).

Yazici, H. & Sever, M. Active control of a non-linear landing gear system having oleo pneumatic shock absorber using robust linear quadratic regulator approach. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, Sage UK: London, England, 232(13), 2397-2411, (2017).