Strength and Damage Tolerance Analysis of a Fiber Reinforced Plastic(FRP) Multi Leafspring of a Light Passenger Vehicle Using Finite Element Analysis

Abstract

In the present scenario, strength of the structures has been the main focus of automobile manufacturers. The suspension leaf spring is one of the potential items for higher strength in automobiles as it accounts more than two times stronger than the conventional steel leaf spring. This helps in achieving more damping capacity, less fuel consumption and resistance against impact loads in the vehicle. The introduction of composite materials made it possible to avoid catastrophic damage due to sudden impact loads that are transferred to the chassis of light passenger vehicle through the leaf spring. In this work, an attempt has been made in replacing the design of a conventional multileaf leaf spring by a composite multileaf leaf spring based on strength ratio without any modification of the existing design of a light passenger vehicle. The materials adopted in the analysis of composite multileaf leaf spring are glass/epoxy, glass jute /epoxy, carbon jute/epoxy. The optimum material combination is determined based on the maximum induced bending stress, material availability and the contact pressure generated between each and every laminate which will influence the unsprung weight of the light passenger vehicle. Due to impact loads acting on the multileaf leaf spring damage tolerance work is also carried out in the composite material that has minimum contact pressure by creating artificial hemispherical damage for varying proportions. The optimum composite multileaf leaf spring is fabricated using filament winding technique. Modeling and contact analysis were carried out for both conventional and composite materials using ANSYS 8.1 software. From the investigations undergone, it is well proved that composite multileaf leaf spring made of glass/epoxy is found to be of higher strength comparing strength ratio, induced bending stress, contact pressure as well as with respect to cost, than the conventional leaf spring and the optimum damage radius due to sudden impact loads is also predicted in the composite multileaf leaf spring.