Research On The Optimization Design Of Complex Equipments' Key Structures Considering Multi-source Uncertainties

In engineering practice,there are uncertainties in many forms and sources.Only when these multi-source and multi-type uncertainties are fully considered in the design process can it be possible to obtain complex equipment with high comprehensive performance.Many domestic and foreign scholars have carried out a series of studies on the uncertainty design method for structures,but there still many shortcomings that need to be further studied.Firstly,most of the current structural scheme optimization methods do not involve fixation and deviation attributes,and it is difficult to solve the multi-objective structural scheme optimization problem with heterogeneous uncertainty attributes.Secondly,the current reliability analysis solution process of the design optimization model will have a slow convergence or even no convergence and optimization solution process is cumbersome and computationally inefficient.Meanwhile,there are few existing structural robustness optimization design methods consider probability and interval variables.Therefore,it is very significant to carry out the complex equipments' key structures research on heterogeneous multi-objective uncertainty structure scheme optimization based on TOPSIS method,reliability optimization design based on adaptive step size reliability analysis and robustness optimization design considering probability and interval variables,which can improve the comprehensive performance of complex equipments'key structures.The main contents of the paper are as follows:The first chapter summarizes the research status at home and abroad of structural scheme optimization design,reliability optimization design and robustness optimization design,analyses the shortcomings in the existing research,puts forward the main research content.The second chapter comprehensively considers cost,benefit,fixation and deviation attributes,constructs a comprehensive decision-making matrices for multi-objective optimization problems of complex equipments' key structures,and proposes a heterogeneous TOPSIS(HTOPSIS)method,gives the equivalent conversion method of the fixation and deviation attributes,realize the unified normalization of each attribute and the determination of positive and negative ideal solutions,calculate and sort the relative closeness coefficient of structure schemes.The third chapter uses probability variables describe known probability distribution uncertain factors,interval variables describe cognitive uncertain factors,establishes the reliability optimization design model of structures considering probability and interval variables,proposes an adaptive step size reliability analysis method,introduces the concept of correction angle to improve the efficiency of structural reliability analysis,and combines the PRSM approximation model and the genetic algorithm to realize the direct solution for the structure reliability optimization design model of hybrid uncertainty structures.The fourth chapter establishes the robust optimization design model of structures considering probability and interval variables,proposes the feasible robustness index of hybrid uncertainties constraint performance and the superiority criterion based on feasible robustness index,sorts the structural design vectors by the relative closeness distance of the negative ideal solution,and combines Kriging approximation model technology,MCS method and genetic algorithm directly solve the critical structure robust optimization model of complex equipment with probability interval variables.The fifth chapter summarizes the research work and main results of this paper,and prospects the future research directions.