Analysis Of Aircraft Taxiing-induced Response With Multiple Wheels And Multiple Landing Gears

To study the taxiing-induced dynamic response of the aircraft with multiple wheels and multiple landing gears due to runway unevenness, base on several reasonable and necessary assumptions, the mathematical model of aircraft in taxiing is established using the d'alembert's principle. It can simulate taxiing inpact properties accurately, it considers in detail the vertical and horizontal motion and pitching about its center of gravity and the significant symmetric elastic modes. Also considered are the nonlinear hydropneumatic landing gear characteristics, the structural flexibility of landing gear, the nonlinear load-deflection characteristics of the tires, the rolling and sliding friction of the tires versus slip ratio, the rolling moments of inertia of the tire and wheel, the pitching motion and the structural flexibility of carriage and the aerodynamic force. The motion equations of the aircraft taxiing in constant velocity are derived. Using the San Francisco Airport 28R runway unevenness as the input, the taxiing-induced response time history can be integrated.The dynamic responses are also obtained by the statistical analysis with PSD method. The significant problem is that the input of runway unevenness is stationary stochastic process and how the oleo-pneumatic shock absorbers could be linearized. These are all presented in details in this paper.With determinate method, the analysis of taxiing-induced response of aircraft with the multiple wheels and multiple landing gears is conducted. The results show that the flexibility of body should be taken into account, especially to the large aircraft. Additionally, the initial parameter of the oleo-pneumatic shock absorbers affects the loads distribution. The reasonable selection of parameters can help to alleviate dynamic response. Based on the above analysis ,a user-oriented computing program is developed, and it's easy to expand the function of the program with landing gear model.Correspondingly, we analyse the taxiing-induced response of the aircraft with PSD method. And get the same conclusion that the flexibility of airframe could affect thetaxiing-induced response of the aircraft.