Dynamic Modeling And Analysis Of Aircraft Landing Gear System

This paper focuses on dynamic response of the nose landing gear system using the numerical simulation method.With the runway surface input of random unevenness,the vertical dynamic responses of the nose landing gear are analyze during taxiing and tracting conditions.Firstly,the mathematical models of the main structure of the landing gear system is established.Based on this,two dynamic models of the nose landing gear are obtained and the nonlinear dynamic equations of the system are derived.Secondly,when studying dynamic responses of the nose landing gear under the random excitation of the runway surface during taxiing,the comparative analysis of dynamic response of landing gear under different models are conducted.It is found that the vertical dynamic response of the strut and tires of the nose landing gear is significantly higher than the case when the aircraft’s pitching motion is not considered.When analyzing the reason for this significant increase,different effects of aircraft pitching motion on dynamic responses of strut of the nose and main landing gear was obtained,and the principle of leverage is applied to explain this difference.Furthermore,the effects of spring force and damping force of the nose landing gear are analyzed.Finally,when studying the vibration response of the nose landing gear during tracting conditions,two dynamic models and their equations of the traction system which based on the spring-plate model of the nose landing gear are established.Through a comparative analysis of the dynamic response of the two models,a simplified model of the traction system is obtained.Further,the influence of the road surface unevenness on the vertical vibration response of different parts of the landing gear system during traction is analyzed.