Analytic Design Theory Of Superimposed Leaf Spring And CAD Software Development

Due to simple structure and high load capacity,superimposed leaf spring become an elastic element of widely used suspension components.Currently,the leaf spring is mostly designed by experience and graphical method,and then the design parameters are determined by validated experiment.But this method is time-consuming,high costs and inaccurate.Previously,domestic and foreign scholars made a lot of research on analytical calculation theory of the superimposed leaf springs,but didn't give analytical calculation methods of equivalent thickness and allowable thickness of the superimposed leaf springs.Therefore,they can not meet the design requirements of splitting.In this paper,firstly the analytical formula of deformation?equivalent thickness and allowable thickness were researched.Based on this,CAD software of superimposed leaf spring will be developed,the specific contents are as follows:(1)The equivalent thickness of unequal length of the overlapping portion of leaf springThrough the force analysis of two pieces of unequal length leaf spring,the deformed analytic formula of equivalent monolithic was given.Utilizing the equal bending deformation of the each leaf spring,the mathematical model of equivalent thickness of overlap portion of unequal superimposed leaf springs was established.(2)The research on equivalent thickness and deformation of unequal length superposition leaf springBased on the equivalent thickness of the overlapping portion of leaf spring,according to the second castigliano's theorem,analytical formula for the monolithic deformation of equal thick for the leaf spring was given;and then,according to the equal deformation principle of different thickness leaf springs at the endpoint and same thickness at the monolithic endpoints,mathematical model of equivalent thickness of unequal superimposed leaf springs was established.(3)The study on maximum stress and allowable thickness of unequal length superposition leaf springAccording to the relationship among the deformation,thickness and load,the formula of pieces stress and maximum stress of overlapping portions for the leaf springs was given.Using the analytic formula of maximum stress,based on the maximum stress is less than the allowable stress,the analytical formula of allowablethickness of the superposition leaf spring was established.(4)The split design method of unequal length superposition leaf springAccording to the calculation formula of deformation,equivalent thickness and allowable thickness,the split design of unequal length leaf spring for superimposed leaf spring was given.(5)CAD software development of leaf springsAccording to split design theory of unequal length overlay leaf spring,using Visual Basic6.0 software for CAD software development.The software can design parameters required by leaf springs,based on the stiffness or vehicle parameters provided by the user requirements.By example calculation for split design of leaf spring,and ANSYS finite element simulation,prototype simulation of leaf springs and instances verificatio n,results show that the analytical split design of leaf spring is reliable,establis hing a better foundation for the CAD development.