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

Abstract

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