Development Of Parameters Design CAD And Characteristic Simulation Software Of Variable Cross-Section Leaflet Spring For Automobile

Leaf spring is one of the important parts of automobile suspension,the smoothness,comfort and safety of automobile is determined by it.With the rapid development of computer-aided design technology,the design method of the less leaf spring with variable cross-sections using experience method and test method can not meet the requirements of digital design.Leaf spring manufacturers urgently need an accurate and efficient digital design software for he less leaf spring with variable cross-sections to improve the quality and level of product design and speed up product development.However,due to the restriction of the forward design theory of the key parameters and the simulation mathematical model of the characteristics of the less leaf spring with variable cross-sections.A digital design software which is accurate,reliable and can realized the integrated functions of the key parameter design and the simulation analysis has not been developed so far.Therefore,it is difficult to meet the demand of the digital production of he less leaf spring with variable cross-sections.In this paper,a series of researches are carried out on the,characteristic simulation mathematical model,key parameters forward design theory,digital design software development and so on.The research work and innovative research results are as follows:(1)Take the actual shapes of the two ends of leaf spring section into consideration,According to the relationship between the stiffness and the moment of inertia of the leaf spring,an analytical formula for equivalent width of leaf spring is established.According to the mechanical model of the ingle-chip root-intensive parabolic leaf spring,using Moore integral,the analytical calculation formulas of the sitiffiness and the stress for it are established.On this basis,The mathematical model of stiffness and stress of the end non isomorphic spring is established.(2)According to the vehicle parameters and the requirements of the stiffness and stress for the leaf spring,the design method and the equivalent splitting method of single leaf spring with variable section are established;According to the analytical formula of it,the design method of its key structural parameters is established;Based on the stiffness of the leaf spring and the requirements of the residual arc height under the rated load,the design method of the free arc height of each leaf spring is established.(3)Qt is selected as the GUI development platform for the parameter design CAD and characteristic simulation software of the variable cross section leaf spring of the automobile.According to the actual design and simulation process of the leaf spring,the software design route is determined.Through the unique event generation and processing mechanism and signal slot mechanism of Qt development framework,each interface is connected in series,andthe interface design and parameter communication of each software module are completed.(4)According to the forward design theory of the key parameters of the few-chip root-intensive parabolic leaf spring with non isomorphic end and the analytical formula of its stiffness and stress,using the mixed programming method of C + +(computer programming language),DLL(Dynamic Link Library),SCR(Auto CAD script language)and APDL(ANSYS parametric language),the functions of parametric design,CAD drawing annotation,Characteristic simulation,and parametric finite element simulation are realized.The software is used to design a few-chip parabolic leaf spring.At the same time,the characteristic test was performed on the designed leaf spring by the test platform.The results show that the relative deviation between the software design and simulation results and the test data meet the requirements of engineering design accuracy.It shows that the established forward design theory of the key parameters of the few-chip parabolic leaf spring and the analytical formula of its stiffness and stress is correct,and the developed parameter design CAD and characteristic simulation software for it is reliable.The development of this software has important engineering application value,which promotes the development of digital design of less leaf spring to a certain extent.