Research On Reliability And Test Verification Of Landing Gear Steering Mechanism Considering Environment Temperature

The landing gear of aircraft is key load bearing part of the aircraft during the takeoff and landing process.The performance of the nose wheel steering mechanism directly affects the safety of whole aircraft.Aircraft landing gear usually works in very complex environment,such as harsh environmental temperature.In order to study the performance of the landing gear mechanism in different environmental temperatures,it is necessary to analyze the reliability of the steering mechanism and verify it in high-low temperature environment.The rack-and-pinion nose wheel steering mechanism is chosen as the research target,by designing the structure preliminarily and checking the strength,the finite element model of the landing gear steering mechanism is established.The meshing process of the rack and the pinion were researched by finite element simulation,the maximum of tooth root bending stresses and contact stresses of the gears are analyzed.The feasibility of finite element simulation method in the analysis of gear rack meshing is verified.The thesis focuses on the model of reliability analysis and the methods for mechanical reliability analysis,establishing the response surface model of artificial neural network on the base of considering the factors which impact the reliability of mechanism.MA700 airplane's nose wheel steering mechanism was analyzed by building the simulation model of the nose wheel steering with the use of LMS Virtual.Lab Motion and MATLAB.After series of simulations,we got the input and output results,and then we use artificial neural network to calculate out the reliability and sensitivity.The design of high-low temperature hydraulic system is carried out,and the test data under different ambient temperature are obtained through functional test.According to the variation of the parameters in the experiment,the experimental data is compared and the influence of different environmental temperatures on the reliability of the mechanism is analyzed.The results of the experiment verify the reliability of MA700 landing gear steering mechanism.