PLY WISE FAILURE ANALYSIS OF MONO LEAF SPRING USING HYBRID C-GFRP COMPOSITES

Abstract

Composite materials are a better alternative for Leaf spring material in automobiles since they have higher stiffness, high impact energy absorption, lesser stresses and also higher strength to weight ratio. The objective is to study the ply wise failure criteria in the composite leaf springs. Leaf springs are modeled and analyzed using ACP PrePost and studied for failure criteria based on four failure theories which are: maximum stress failure theory, maximum strain failure theory, Tsai-Hill failure theory and Tsai-Wu failure theory. Failure load based on these theories is calculated by conducting a parametric study. To improve the maximum failure load, hybrid composites are designed and analyzed by replacing the top, bottom and center layers of the composite laminate. The four different cross-sections which are analyzed are Eglass/epoxy, HC1, HC2 and HC3. The study shows that replacing the top, bottom and center layers does improve the maximum failure load. Although this introduces higher stresses in the component, the stresses in the Eglass/epoxy material at the same positions from the center of the laminate are reduced. HC3 shows 30.7% increment in failure load by considering only vertical loads and 20.8% increment in failure load by considering vertical, side loads and twist moment simultaneously. There is an agreeable error of 1.44 – 1.65% in the results obtained for deformation and 0.88 – 1.33% for failure load between simulation and theoretical calculations.

Mechanical properties of the Eglass/epoxy material are evaluated by conducting tensile test and three-point bending test. Mono leaf spring similar to the dimensions of Maruthi 800 vehicle is made using hand layup method. The load vs deformation results of leaf spring show a good agreement between the experimental and the simulation values.