Fatigue Life Analysis And Research Of Leaf Spring Based On Finite Element

Leaf spring is elastic parts which widely is used in automobile suspension system,mainly used for the non-independent suspension vehicle and bear the impact load from a road in the process of driving the car.Its stiffness and fatigue life have a direct influence on the reliability of the vehicle and driving safety.Although the structure of leaf spring is simple,due to its nonlinear and geometric nonlinear,using the conventional computation method to calculate its results is relatively inaccuracy.In this paper,the leaf spring fatigue life calculation is established on the basis of finite element results.In order to improve the accuracy of finite element calculation results,the friction coefficient between inter-leaf is identified.Verify the correctness of the identification method for coefficient of friction and the rationality of leaf spring performance by comparing the test results.Then calculate the fatigue life of leaf spring.The main achievements of this research are as follows:The leaf spring geometric model was build using Pro/E 5.0 software based on the structural parameters on leaf springs.In the ANSYS software,imposed boundary condition on finite element model in accordance with the actual leaf spring assembly and test requirements,build finite element model of leaf spring.This paper takes the surface method to build relationship between friction coefficient and displacement for leaf spring.Then a set of equivalent friction coefficient was found using linear programming method to improving the accuracy of finite element model of leaf spring.Calculated the stress distribution and stiffness of leaf spring and compared with the testing results of leaf spring performance,it will verify the correctness of finite element model.According to the leaf spring characteristics,using theoretical equations calculate the S-N curve of material.Furthermore,the S-N curve of material should be correction with the effect of leaf spring fatigue-related factors to obtain the S-N curve of the leaf spring.The leaf spring fatigue life was calculated by Ncode-designlife combined with leaf spring S-N curve,finite element analysis and standard load spectrum.Determine the danger zone and compared with results of fatigue tests and verifies the correctness of results.The studies show that finite element technology in study of leaf spring performance with higher accuracy.In addition,the use of leaf spring fatigue life prediction of the fatigue analysis software can not only predict service life of the spring in advance but also can shorten the development cycle and reduce costs,has the guidance meaning for the design of new product.