| The static blade joint adjustment mechanism is the key device to realize the adjustment of different working conditions of aeroengine,and the reliability of its motion accuracy is the key problem in the design of high-performance aeroengine.Because of the uncertainty factors such as manufacturing error,material property and working load,the kinematic accuracy analysis of the mechanism needs the uncertainty theoretical model,which brings many challenges to the reliability analysis and optimization design of the aeroengine stator blade joint adjustment mechanism.Therefore,by introducing the parameter randomness of the aeroengine static blade joint adjustment mechanism,combined with the fractional moment maximum entropy method,the probability distribution of the motion error of it is obtained.The fractional moment method for sensitivity analysis of mechanism motion accuracy is proposed.The effects of physical parameters such as the radius of linkage ring,the length of rocker arm,the length of adjustable end of crank and the angle between fixed end and adjustable end of crank on the motion error of mechanism are studied.Combining fractional moment maximum entropy and quantile-based SORA method,the reliability and robustness optimization design of static blade joint adjustment mechanism is carried out.The main contents of this paper are as follows:(1)Comparative research on structural reliability methods based on different fractional moment maximum entropy modelsBy combing the maximum entropy optimization model in the current literature,this paper makes a comparative analysis from the model fitting accuracy,model error and model optimization success rate,summarizes the advantages and disadvantages of the existing maximum entropy optimization model and its applicability,and provides an accurate and more applicable reliability analysis method for different engineering practices.(2)Research on structural reliability sensitivity analysis method based on fractional moment maximum entropyIn order to investigate the influence of mean value and standard deviation of random variables on structural reliability,a reliability-based sensitivity analysis method based on fractional moment and maximum entropy method is proposed,and the reliability-based sensitivity analysis is carried out for multivariate complex structures.Firstly,the fractional moments of structural response are treated by multiplicative dimension reduction expansion and Gaussian integral,and then the sensitivity analysis index based on moments is derived.Secondly,the maximum entropy method based on fractional moments(ME-FM)is used to reconstruct the probability distribution of structural response,and then the sensitivity analysis index based on failure probability is derived.The efficiency and accuracy of the method are verified by typical numerical cases in literature(3)Research on structural reliability optimization design method based on fractional moment maximum entropy methodCombining the fractional moment maximum entropy method and the sequential optimization method based on quantile(q-SORA),the reliability-based optimization design of structural response is carried out.In other words,the maximum entropy method is used to calculate the reliability quantile to solve the defects of the traditional SORA method.In order to improve the applicability of the reliability optimization method,different maximum entropy models are selected according to different engineering practices.In this chapter,the traditional SORA method is used as a comparison benchmark,and the efficiency and accuracy of the method are verified by typical numerical cases in the literature.(4)Reliability and robustness optimization design of aeroengine stator blade joint adjustment mechanismIn this paper,the homogeneous coordinate method is used to deduce the motion process of the static blade joint adjustment mechanism.Under the condition that the rocker arm of the two cascade adjustment mechanisms moves under the specified rotation law,the uncertainty of the physical parameters of the joint adjustment mechanism is considered,and the reasonable maximum entropy method is selected to reconstruct the probability distribution of the motion error of the joint adjustment mechanism,The structural reliability sensitivity analysis method based on the maximum entropy of fractional moment is used to obtain the reliability sensitivity ranking of input random variables;Finally,the maximum entropy and q-SORA method are used to optimize the reliability and robustness of the aeroengine stator blade joint adjustment mechanism. |
PDF Full Text Request