Research Of Parametric CAD System Of Railway Vehicle Axle Based On CATIA Platform

With the rapid development of railway transportation and the significant progress of information technology,the clients' requirements to improve the quality and efficiency of the product design are getting higher and higher.The mainstream three-dimensional CAD system on the market up to the present time has its industry versatility,but the demands of the clients are personalized.Therefore,to conduct the secondary development of the three-dimensional design software so as to achieve the need of professional design is of great significance.As one of the key components of the railway vehicle bogie,the railway vehicle axles,comparing with other comyponents,whose structure claims a higher degree of standardization.So it is of significance in engineering practice to develop a railway vehicle axle parametric design system so that we can achieve the integration of the axle design and the strength calculation.This paper introduces the main methodology and basic principles of the secondary development based on C ATI A V5 platform systematically and focuses on employing CATIA V5 CAA secondary development technology to develop the secondary development of axle design system.It introduces the variable structure of the parametric design method which is more flexible than the traditional parameterization and meanwhile devises an operative interface of the railway vehicle axle parametric design and strength analysis fitting closely with the CATIA interface.The design methodology has the functions of updating,expanding and maintaining the axle template.This paper studies grid automatic generation technology within the advanced simulation module in CATIA.It processes the surface the axle with the tetrahedral mesh in a discrete way to generate the axle finite element and facilitates the subsequent solution of the bending moment,nodal stress and safety coefficient.It abstracts the loading model of the axle system which is based on the three-dimensional modeling function of CATIA.What is more,it realizes the visualization of the axle loading process by creating the loading interface of the axle load.It customizes the load attributes and indicates them with labeled arrows to achieve the visualized designation of the axle load type,location,direction and size.Furthermore.it can load and output in different conditions based on the load model and calculate the axle load according to the basic princples of mechanics.It realizes the visualized designation of parametric solution of axles such as stress concentration coefficient,permissible stress,interference fit area and minimal life section based on the secondary development technology.The verifying calculation of the strength of the axle is carried out according to the stipulated algorithm of axle in EN13103 and EN13104 and then calculate the bending moment of the axle,node stress and safety coefficient by programming.In this paper,the author studies the basic principle of the visualization of nephogram by OpenGL.The author develops the visualization system of axle stress and safety coefficient with the graphics processing interface in C ++ and OpenGL,and invokes the line graph processing technology in EXCEL to realize the bending moment diagram of the axle and the chart of the calculation result of the minimal life section.It is of great significance in engineering practice for the parametric CAD system of railway vehicle axle which has realized the integrated the CAD design of axle with the strength analysis,and has verified the feasibility of the customized specialization of the secondary development on railway vehicle's related components on CATIA V5 platform.