International Journal of Modern Engineering Research (IJMER) www.ijmer.com Vol.2, Issue 4, July-Aug 2012 pp-1920-1922 ISSN: 2249-6645 www.ijmer.com 1920 | P a g e Manas Patnaik 1 , Narendra Yadav 2 , Ritesh Dewangan 3 , 1,2,3 (Department of Mechanical Engineering, Rungta College of Engineering & Technology, Raipur-492001-India Abstract : This work is carried out on a mono parabolic leaf spring of a mini loader truck, which has a loading capacity of 1 Tonnes. The modelling of the leaf spring has been done in CATIA V5 R20. And for finite element analysis the model was imported in the static structural analysis workbench of CATIA V5 R20. The finite element analysis of the leaf spring has been carried out by initially discretising the model and then applying the relevant boundary conditions. Max Von Mises stress and Max Displacement are the output parameters of this analysis. In order to study the behaviour of parabolic leaf spring, Design of experiments has been implemented. In DOE, input parameters such as Eye Distance & Depth of camber have been varied and their affect on output parameters have been plotted. Keywords: Computer Aided Design (CAD), Camber, Design of Experiments (DOE), Eye Distance, Finite Element Analysis (FEA), Parabolic Leaf Spring (PLS). I. INTRODUCTION Parabolic Leaf sprigs are essential suspension elements used on mini loader trucks necessary to minimize the vertical vibrations, impacts and bumps due to road irregularities and to ensure safety of the loaded cargo. Parabolic Leaf springs are widely used for automobiles. The Parabolic leaf spring absorbs the vertical vibrations and impacts due to road irregularities by means of variations in the spring deflection so that the potential energy is stored in spring as strain energy and then gradually released to maintain comfort. The finite element analysis (FEA) is a computing technique that is used to obtain approximate solutions to the boundary value problems in engineering. It uses a numerical technique called the finite element method (FEM). It is now accepted by major industries across the world and a company that is able to verify a proposed design will be able to perform to the clients specifications prior to manufacturing or construction. In the present work, leaf spring has been analyzed for static strength and deflection using 3D finite element analysis. CATIA V5 R20 has been utilized in the creation of the three dimensional model and its static structural workbench for analysis when subjected to vertical loads. The variation of bending stress and displacement values are computed. To add on the different combinations of input parameters (camber & eye distance) have been taken into account & its influence on bending stress and max deflection has been studied. II. Parabolic Leaf Spring & Dimensions A more modern implementation of old leaf springs is the parabolic leaf spring for automobiles. The new innovative design is characterized by the use of less leaves whose thickness varies from the center to the outer side following a parabolic pattern. The mathematical equation between the thickness & the length of the spring is that of a parabola & hence it has been named as parabolic leaf spring. This results in less inter leaf friction, because of which the only contact point between the springs in vehicle is at the end and the center where the axle is connected. Spacers used in the new design prevent the other parts collisions. Besides being less in weight the main benefit of parabolic springs is their greater flexibility, which is translated as a high ride quality of the vehicle. It gives us the high ride quality which refers to the high degree of safety to the riders from the uneven road and gives high level of comfort. Modified version of leaf springs is the parabolic leaf springs for automobiles and has better load bearing capacity with less weight. Other benefits include improved fuel economy, load carrying capacity & enhanced suspension. In the present work parabolic leaf spring of a mini loader truck is considered for analysis. The modeling of the PLS has been carried out in CATIA V5 R20 and has the following dimensions: 1. Camber – 90.81mm 2. Distance between eyes(Eye Distance) : 1025mm 3. Thickness at the central part : 10.81mm Note: The above dimensions have been taken with the help of an inextensible measuring tape and a vernier caliper and then the procedure of modeling the spring was initiated. The basic views of the considered parabolic leaf spring are shown in fig. 1. Fig.1 Front & Top view Note : All dimensions are in mm III. EXISTING MATERIAL The material used for experimentation is EN45 and its mechanical properties has been mentioned in Table-1 Table--1 Material Young s Modul us (E) Gpa Poisso n's Ratio( Μ) Densi ty (Kg/ M 3 ) Yield Stren gth( Mpa) EN IS(Old ) EN4 5 55Si2 Mn90 200 0.3 7850 1500 Study of a Parabolic Leaf Spring by Finite Element Method & Design of Experiments