Parametric Design And Research Of Three-phase Tapered Leaf Spring

Leaf Spring is a common elastic component in the dependent suspension. It transfers the force and moment from the wheel to the body, decreases the impact load from the road surface, attenuates the vibration due to this impact load, and assures the normal running of the vehicle. Leaf spring also acts as a guide mechanism of the suspension, which simplifies the structure of the suspension, makes the maintenance conveniently, and decreases the production cost. In order to take full advantage of the material, the leaf spring is designed as a beam with constant strength. In contrast with the other leaf spring suspension, three-phase tapered leaf spring suspension has the best stiffness characteristic, which stiffness curve is closed to the ideal stiffness curve. With the improvement of the manufacturing process of the tapered leaf spring, three-phase tapered leaf spring is being used more and more widely. This paper research on the parametric design and analysis about three-phase tapered leaf spring.According to design theory and experiment method of the three-phase tapered leaf spring, this paper study the methods and processes about the structure parameters design and performance parameters analysis of the three-phase tapered leaf spring. The whole parametric design and analysis process is divided into three modules. They are the structural optimization design, finite element performance simulation and simulation of fatigue life.In the module of structural optimization design: Based on the theory of optimize design, the optimal mathematical model for three-phase tapered leaf spring with prestress is established. The three-phase tapered leaf spring is optimized using MATLAB programming. The result shows that the spring has the minimum weight with required strength and stiffness. The optimization method improves design efficiency of leaf spring greatly.In the module of finite element performance simulation: In accordance with the actual leaf spring geometry and material properties, the FEA model of the three-phase tapered leaf spring considering large deformation, interleaf friction and contact simultaneously is built using ANSYS based on nonlinear finite element method. In order to proves the validity of this FEA model and the rationality of the spring’s structure which was designed using the modular of structural optimization design, the assembly and the elastic characteristic simulation are built. If the simulation results meet the design requirements, the damping ratio of this three-phase tapered leaf spring was obtained after a damp characteristic analysis according to the theory of mechanical vibration. It offers suggestions for the design of shock absorber. If the simulation result does not meet the design requirements, it must return to the module of structural optimization design, and restart the whole process of parametric design until it meets the design requirements. The APDL programming language is used to achieve the parametric design of leaf spring in the entire process of modeling and Analysis.In the module of simulation of fatigue life: A fatigue analysis simulation is implemented by ANSYS/Fatigue with the help of the material S-N curve, considering the impact of the leaf spring real feature on fatigue characteristics. We must verify the leaf spring’s fatigue life whether meets the life requirement. If it meets, the entire parametric design process is over. If it does not meet, it must return to the module of structural optimization design, and restart the whole process of parametric design until the life meets the requirement.In this paper, a parametric design method for three-phase tapered leaf spring which contains three modules of structural optimization design, finite element performance simulation and simulation of fatigue life. It can get the structure parameters and performance parameters of the leaf spring. Through the analysis of the stiffness, damping and fatigue life and other parameters, it can decide the next design. If it does not meet the design requirement, it must return to the module of structural optimization design, and restart the whole process of parametric design until they meet the design requirement. Then we can produce the sample and do test, finally input into mass production. So it can save the tedious process of calculation and analysis. And it can not only improve the development efficiency, but also save the development costs. It has a higher theoretical study and usability.