Effects of design parameters on the fatigue behavior of leaf springs used in commercial vehicles

In this study, leaf springs which are one of the most important components in commercial vehicles, are investigated in terms of design parameters. There are three types of leaf springs. These are parabolic, conventional and airlinkers. Steel materials such as 55Cr3, 51CrV4, 52CrMoV4, 51B60H and 5160H are being used for leaf springs. The material to be used is defined according to rolled layer thickness that varies with load carrying capacity of vehicles. As a result of improving the state of the art technologies and competition environment created by vehicle manufacturers, there are many studies on meeting customer requirements. In this study, parabolic leaf springs manufactured from 51CrV4 and 51B60H hot rolled steel materials have been investigated in terms of fatigue behavior. In addition, some properties which are given on technical drawings such as surface roughness and residual stress levels are also analysed. Surface rougness values derived from different descaling methods, generated residual stress values associated with stress shot peening process and their effect on fatigue life of leaf springs are demonstrated with fatigue tests. Computer aided analysis have been performed to demonstrate the effect of design parameters, such as leaf width and eye thickness, on fatigue life and static stress values.