Analytical and Experimental Studies on Fatigue Life Prediction of Steel and Composite Multi-leaf Spring for Light Passenger Vehicles Using Life Data Analysis

This paper describes static and fatigue analysis of steel leaf spring and composite multi leaf spring made up of glass fibrereinforced polymer using life data analysis. The dimensions of an existing conventional steel leaf spring of a lightcommercial vehicle are taken and are verified by design calculations. Static analysis of 2-D model of conventional leafspring is also performed using ANSYS 7.1 and compared with experimental results. Same dimensions of conventionalleaf spring are used to fabricate a composite multi leaf spring using E-glass/Epoxy unidirectional laminates. The loadcarrying capacity, stiffness and weight of composite leaf spring are compared with that of steel leaf spring analyticallyand experimentally. The design constraints are stresses and deflections. Finite element analysis with full bump load on3-D model of composite multi leaf spring is done using ANSYS 7.1 and the analytical results are compared withexperimental results. Fatigue life of steel leaf spring and composite leaf is also predicted. Compared to steel spring, thecomposite leaf spring is found to have 67.35 % lesser stress, 64.95 % higher stiffness and 126.98 % higher naturalfrequency than that of existing steel leaf spring. A weight reduction of 68.15 % is also achieved by using composite leafspring. It is also concluded that fatigue life of composite is more than that of conventional steel leaf spring.