Research On Modeling And Simulation Of Motion Functional Reliability For Aircraft Landing Gear Lock Mechanism

The landing gear retracting and extending system is the key link to complete the safe retracting action of the landing gear and is of great significance to ensure the safe take-off and landing of the aircraft.The uplock mechanism is an important part of the landing gear retracting and extending system and its motion reliability is one of the key performance indicators of the landing gear.With the continuous development and update of the safety and reliability indicators of military aircraft,higher requirements are put forward for the motion reliability of the uplock mechanism.In view of this,this paper takes the uplock mechanism of landing gear of a military aircraft as the research object,and carries out reliability analysis and simulation technology research on its motion function reliability according to the jamming failure mode.The research in this paper can provide reference for the motion functional reliability modeling of other military or civil aircraft landing gear lock mechanism.The main contents include:(1)The background and significance of the research are elaborated,and the theory of mechanism motion reliability and the modeling technology of mechanism motion reliability and the research status of reliability simulation analysis are summarized.In this paper,the calculation method of mechanism motion reliability and the research status and problems of mechanism motion functional reliability engineering are introduced.Finally,the research objectives and contents of this paper are put forward.(2)According to the multi-factor coupling characteristics and gradual change characteristics of mechanism motion function failure,the failure mechanism analysis of a typical type of aircraft landing gear is completed.This paper describes the working principle of the uplock mechanism,and obtains its implicit limit state function and the main factors leading to the clamping failure of it by combining FTA and FMEA analysis.The theoretical analysis of single factor and multi-factor coupling leading to the clamping failure of the uplock mechanism is carried out respectively.The dynamic model of the uplock mechanism under multi-factor coupling is established.(3)A new method for evaluating the mechanism motion functional reliability is proposed.Considering the randomness of input errors,a factorial analysis experiment is designed by using PB method.The significant analysis of several basic random variables affecting the uplock mechanism motion functional reliability is carried out,and the main influencing factors are obtained.The experiment is designed by Box-Behnken method,and the limit state of uplock mechanism is obtained by using response surface fitting method,and its reliability is calculated.Considering the gradual variation of input error,the limit state function of uplock mechanism is obtained by using linear response surface method under the influence of both non-time-varying and time-varying factors,and then the reliability degradation law of upper locking mechanism is obtained.Finally,based on the given reliability index,the safe working life of the upper locking mechanism is given.(4)The simulation software and the theory of LMS Virtual.Lab are introduced.The rigid-flexible coupling model of the uplock mechanism is established by using LMS Virtual.Lab Motion module,and its dynamic performance is simulated and analyzed.Based on the simulation model,the jamming reliability analysis and reliability calculation of the uplock mechanism considering the randomness of the influencing factors obeying the normal distribution are carried out by using Monte Carlo method.