FATIGUE LIFE PREDICTION OF COMPOSITE SEMI - ELLIPTICA L LEAF SPRING FOR HEAVY VEHICLE

A leaf spring is a simple form of spring, commonly used for the suspension in wheeled vehicles. Leaf Springs are long and narrow plates attached to the frame of a trailer that rest above or below the trailer's axle. There are mono leaf springs, or single - l eaf springs, that consist of simply one plate of spring steel. These are usually thick in the middle and taper out toward the end, and they don't typically offer too much strength and suspension for towed vehicles. Drivers looking to tow heavier loads typi cally use multi leaf springs, which consist of several leaf springs of varying length stacked on top of each other. The shorter the leaf spring, the closer to the bottom it will be, giving it the same semielliptical shape a single leaf spring gets from bei ng thicker in the middle. The objective of this paper is to Predict the fatigue life cycle for crack initiation at maximum stress location in the Leaf spring.. The design constraints are stresses and deflections. The aim of this project is to study exist ing semi elliptic leaf spring and optimize the critical part like eye, bolt etc. to minimize the overall weight of the assembly without hampering its structural strength. It also involves geometrical and finite element modeling of existing design and optim ized design. Geometrical modeling is carried out by using CATIA V5 and finite modeling in ANSYS14.0. Results of Static, and fatigue analysis of existing design and optimized design are compared. The optimization is carried out by changing the material for semi elliptic leaf spring. The material used semi - elliptic leaf spring is a composite material such as E GLASS EPOXY.