Dynamic Analysis And Optimization Of Bolt Connection Composite Structure

Bolt connection is one of the most popular connection methods for composite structure applications,and it is widely used in various engineering fields such as automobiles,ships,civil engineering and aerospace.Bolt connection connects two or more sub-structures into one body,and plays the role of connection,sealing,force transmission and movement.The mechanical properties of the connection part have an important influence on the dynamic characteristics of the overall structure.In the bolted combined structure,the bolt assembly connection process,the type of bolted connection and the environment of the combined structure significantly affect the dynamic characteristics of the combined structure.How to predict the dynamic characteristics of the bolted combined structure to optimize the design of the structure It is a challenging problem.This paper takes the bolted connection composite structure as the research object,firstly discusses the bolt connection structure modeling method,and then conducts the dynamic analysis of the bolt connection composite structure.On this basis,the related problems of the dynamic optimization of the bolt connection composite structure are studied.The main content as follows:First,it summarizes the research status of bolted connection composite structure modeling method,frequency response sub-structure analysis method and structure optimization method;summarizes the modeling characteristics and application of the theoretical constitutive model and numerical unit model of the bolted connection structure,and summarizes Several commonly used theoretical modeling methods and their characteristics,including the spring damping model,rigid contact surface coupled beam element model,full three-dimensional finite element model,combined surface element model,virtual material model and other finite element modeling methods.Model points and applicable conditions;taking the connection system of a low-speed machine with a bolted connection structure as an example,different simplification methods are used to model the different bolt structures of the low-speed machine connection system,and a method for estimating the parameters of the bolt connection structure is given,which is the follow-up bolt The dynamic analysis and optimization design of the connected composite structure lay the foundation.Secondly,based on the sub-structure method of frequency response function,the dynamic analysis of the bolted connection composite structure is carried out.Discuss the respective characteristics of different frequency response sub-structure methods,establish the bolted beam structure sub-structure model in MATLAB,use the RC method in the frequency response sub-structure analysis method to analyze its dynamics,and establish the overall structure in ANSYS The finite element model validates the method,and the comparison results show the correctness of the method;in addition,for the bolted shell structure,in the finite element analysis software,the sub-structure frequency response comprehensive analysis method and the overall modeling analysis are respectively adopted The method performs frequency response analysis on it,and the calculation results are very consistent,and the frequency response substructure analysis method has the advantages of high calculation efficiency.Finally,combining the structural dynamics analysis theory and the structural optimization method,the frequency optimization research of the bolt connection composite structure is carried out.The basic theory and frequency optimization method of structural dynamics analysis theory,structural optimization theory and SIMP optimization method are introduced.The SIMP method is used to optimize the frequency of the simple bolted combined structure,and the results verify the effectiveness of the method;after that,for the complex bolted combined structure(low-speed machine structure),a dynamic model is established,and the natural vibration and transient are performed.Based on the response results,the dynamic analysis takes the connection system parameters and the fuselage structure as the research objects,and carries out the frequency optimization design.The analysis results have certain practical reference value for the vibration analysis and dynamic optimization of the bolted combined structure.