Research On Reliability Modeling Method Of Aeroengine Rotor System Based On Fault Analysis

Aircraft engine as a precise and complex high-speed rotating machinery in plays an important role in the field of aviation,including the complex rotor system itself and in the complex environment for a long time,due to its various fault failure modes coexist,the reliability of the rotor system directly determines the aviation engine even the safety of the whole aircraft system.Therefore,it is necessary to study the fault mode of aeroengine rotor system and analyze its reliability based on fault analysis.In this paper,the dynamic simulation of the rotating subsystem based on the unbalance and misalignment coupling fault is carried out by using MATLAB software to analyze the fault response characteristics of the system.A reliability model is established to calculate the reliability of rotor system with coupling faults under the influence of various variables.Specific research contents are as follows:（1）For aviation turbojet engine in a high pressure turbine rotor system FMECA analysis,find out its all possible failure modes and determine each failure harm degree,the results show that balance of the fault and the fault is in two of the most prone to rotor system fault,after the article is based on these two kinds of fault coupling dynamics simulation analysis and reliability analysis.（2）In the introduction or off balance of the fault and failure principle of the fault and dynamics model,using the lumped mass method of degree of freedom and Lagrange principle to deduce imbalance,in the wrong and the coupling fault rotor dynamics equation,select group within the test bench parameters by using the Matlab software simulation analysis was carried out on the model,get the failure time domain response and frequency response characteristics of the system.On the one hand,the fault diagnosis of the system is carried out,and on the other hand,the displacement of the rotor system varies with time is obtained,which can provide the original data for calculating the reliability of the faulty rotor system in the following paper.（3）The mechanical failure comprehensive test platform（MCDS）is used to verify the unbalanced,misaligned single faults and coupled faults.After comparing with the previous simulation analysis results,it is found that they are highly consistent with the amplitude and frequency response of the faulty system.,And then verify the correctness of the fault system dynamic model and simulation results.（4）The traditional stress-strength interference model is improved to make it escape from the interference analysis.The displacement standard and the average displacement of coupling fault system response simulated above are set as the standard normal distribution.Meanwhile,considering the complexity of rotor system working state and environment,the engineering variation coefficients are set as 0.03,0.06 and 0.1,respectively.The data are brought into the reliability model for reliability analysis,and the influence law of different angular velocity,unbalance and misalignment on the reliability of the rotor subsystem is analyzed.