Research On 3D Digital-analog Information Extraction Technology And Transmission Rules Of Aircraft Hydraulic Pipelines

With the rapid development of computer technology,CAD and CAE technology have been involved in the entire design and manufacturing process of aircraft hydraulic pipelines.It has become a necessary technical means to use computer resources to help create,modify,analyze or optimize the design of virtual prototype of aircraft hydraulic pipeline.The modern aircraft hydraulic pipeline system is developing towards high pressure and light weight,which makes the vibration problem of aircraft hydraulic pipeline more significant.Engineers are faced with the challenges of incompatibility between CAD and CAE models,difficulty in extracting CAD model information,and long period of CAE model establishment and analysis.In view of these problems,this thesis studies the key technologies in the extraction,transmission and utilization of aircraft hydraulic pipeline model information for CAE,realizes the automation and generalization of different pipeline digital analog information extraction and the modularization and integration of pipeline digital analog information transmission,and improves the efficiency of aircraft hydraulic pipeline digital analog information extraction and utilization in CAD/CAE integration.The main work of this thesis is as follows:(1)Research on Extraction Technology of 3D digital analog geometric information of aircraft hydraulic pipeline.The design principle of the conduit structure is analyzed,the general extraction method of the geometric information of the hydraulic pipeline conduit is realized by using the CAA secondary development method of CATIA,and the conduit data is obtained.The commonalities and differences between CAD model and CAE model of aircraft hydraulic pipeline are analyzed,and the structural characteristics of different pipeline accessory parts clusters are studied.Using the modeling idea of CSG,a feature-based pipeline accessory geometric information extraction method is proposed to obtain the geometric parameters of pipeline accessories;This thesis studies the storage and construction method of the database,designs and constructs the CAE oriented pipeline accessory database,solidifies and stores the geometric parameters of each pipeline accessory,and improves the efficiency of information reuse.(2)Research on 3D digital-analog topology information extraction of aircraft hydraulic pipeline.Focusing on the identification,construction and utilization of topological information of aircraft hydraulic pipeline system,the assembly model representation of CAD software is studied,and the intersection detection method of parts bounding box based on position and attitude transformation is proposed to simplify the assembly model representation and obtain the adjacency relationship between parts.By mapping the pipeline parts to network nodes and the adjacency relationship between parts to network edges,the pipeline assembly adjacency network diagram is obtained by using the rapid construction algorithm of pipeline system topology relationship.Based on the overall topological relationship,the undirected graph of the pipe network is constructed,and the generation algorithm of the directed graph of the pipe network considering the oil flow direction is extracted,so as to effectively judge the flow direction of the pipeline hydraulic oil,and provide the basis for automatically creating the fluid medium and setting the boundary conditions of the flow in the CAE analysis of the pipeline.(3)Research on data module division and transmission rules of aircraft hydraulic pipeline.Through the analysis of pipeline digital analog information transmission,combined with the commonness of design intention and simulation intention of parts in the pipeline,this thesis explores the general design structure of aircraft hydraulic pipeline with the idea of modularization,puts forward the module division method of aircraft hydraulic pipeline based on community discovery,and classifies the pipeline data according to the structure and function,It improves the efficiency of parts association information retrieval when outputting pipeline data;Based on the results of module division,the naming rules and data content forms of various data files are given to maximize the universality of CAE system data reading and pipeline finite element modeling.(4)Research on the realization method of digital-analog information of aircraft hydraulic pipeline.The general process of digital-analog information extraction and transmission of aircraft hydraulic pipeline is sorted out,and the research results are applied to the typical aircraft hydraulic pipeline solid model.The geometric information of conduit and pipeline accessories is extracted,and the adjacency graph of pipeline assembly is constructed.The pipeline data is sorted and output by applying the algorithm of automatic generation of directed graph of pipeline network and the method of dividing aircraft hydraulic pipeline modules based on community discovery.Finally,the output data is used to carry out finite element modeling and pulsation simulation analysis and verification on the pipeline.The agreement between the effective utilization of data and the simulation results verifies the feasibility and effectiveness of the method proposed in this thesis.