Mono Composite Leaf Spring for Light Weight Vehicle – Design, End Joint Analysis and Testing

The automobile industry has shown increased interest in the replacement of steel spring with fiberglass composite leafspring due to high strength to weight ratio. Therefore; the aim of this paper is to present a low cost fabrication ofcomplete mono composite leaf spring and mono composite leaf spring with bonded end joints. Also, general study on theanalysis and design. A single leaf with variable thickness and width for constant cross sectional area of unidirectionalglass fiber reinforced plastic (GFRP) with similar mechanical and geometrical properties to the multileaf spring, wasdesigned, fabricated (hand-lay up technique) and tested. Computer algorithm using C-language has been used for thedesign of constant cross-section leaf spring. The results showed that an spring width decreases hyperbolically andthickness increases linearly from the spring eyes towards the axle seat. The finite element results using ANSYS softwareshowing stresses and deflections were verified with analytical and experimental results. The design constraints werestresses (Tsai-Wu failure criterion) and displacement. Compared to the steel spring, the composite spring has stressesthat are much lower, the natural frequency is higher and the spring weight is nearly 85 % lower with bonded end jointand with complete eye unit.