Design and Analysis of Leaf Spring for Light Vehicle Mini Truck

Abstract

In present scenario weight reduction is the main focus of an automobile manufacturer. Leaf spring is an important component for any automobile. Generally leaf spring is used for suspension purpose in heavy vehicles. These springs are mainly made of steel material which having more weight. In order to reduce weight, here composite leaf spring is used instead of steel leaf spring.

This dissertation describes the design and static structural analysis of steel leaf spring and laminated composite leaf spring. The dimensions of an existing conventional steel leaf spring of a light commercial vehicle mini truck are taken and are verified by design calculations. Static structural analysis of a 3-D model of conventional leaf spring is performed using ANSYS. Same dimensions are used in composite multi leaf spring using carbon/Epoxy and Graphite/Epoxy unidirectional laminates. The load carrying capacity, and weight of composite leaf spring are compared with that of steel leaf spring. The fatigue life is also calculated using analytically as well as using ANSYS for steel leaf spring. The frequency and mode shapes are determined using modal analysis. The size optimization is carried out for further mass reduction of composite leaf spring. The thickness of each leaf is reduced as a result of size optimization. The mass reduction has been achieved nearly 88.97 % using composite mono leaf spring. Residual stress generated in each leaf is also calculated analytically.