Mechanical Engineering Department, Vindhya institute of technology and science

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1 OPTIMIZATION IN THICKNESS OF LEAF SPRING OF FORCE MOTORS TRAX CRUISER USING DIFFERENT COMPOSITE MATERIALS FOR STRESS AND MINUMIUM DIFFECTION USING FEA ANALYSIS Chetan Kale 1, Prof.Ganesh Kesheorey 2 1 M.Tech (Machine Design), 2 Professor Mechanical Engineering Department, Vindhya institute of technology and science Abstract: The work is agreed out on composite leaf spring of a commercial vehicle Force Motors Cruiser s. The aim of this work is to accomplish design and analysis of composite leaf spring with experimental design consideration and loading condition. The material of leaf spring is Graphite Epoxy, AFRP and CFRP (Graphite Epoxy, Armid, Carbon Fiber reinforced composite)... The design of composite leaf spring is prepared and analyzed using Pro-E and ANSYS14.5 for the deformation and stresses under defined loading condition. The result compared for validation with steel leaf spring which material has50 Cr 1 V 23. The data of conventional leaf spring is taken with varying thickness for evaluation of result and Static analysis is performed. Keywords: CFRP, AFRP, composite, ANSYS14.5, Static Analysis. 1. INTRODUCTION Automotive industries need great amount of metal, alloys for producing dissimilar parts of the vehicle. The substitution of metals was a distant dream but due to rapid development in glass, polymers, ceramics, synthetic fibers and some organic and inorganic substances have been proved as the turning point [1]. More interesting side is, by combining two or more materials one can obtain improved mechanical properties of materials. Composites have better properties such as high specific strength, stiffness and hardness [2]. Due to the mentioned properties composite find wide range of applications not only with respect to properties but also with its weight and cost effectiveness [3]. Leaf springs are largely used in suspension systems to absorb shock loads in automobiles like light motor vehicles, heavy duty trucks and in rail systems. It carries lateral loads, brake torque, driving torque in addition to shock absorbing. The advantage of leaf spring over helical spring is that the ends of the spring may be guided along a definite path as it deflects to act as a structural member in addition to energy absorbing device. According to the studies made a material with maximum strength and minimum modulus of elasticity in the longitudinal direction is the most suitable material for a leaf spring [4].In this analysis Graphite Epoxy, CFRP and AFRP leaf spring is compared with varying thickness [5]. Static testing condition is applied and result is compared by steel models of leaf spring. 2.LITRETURE REVIEW Before starting any dissertation work, the literature review of the topic is must, because it helps us in knowing the amount of work that has been done in that topic by the different researchers. It also helps us in doing the further work by taking the reference of the previous work done in the best possible way. Mahmood M. shokrieh and davood Rezaei have also worked on analysis and optimization of a composite leaf spring. In this research, they consider light vehicle rear suspension system with four-steel leaf spring for analysis of stress and deflection by using ANSYS V 5.4 software.[1] Pankaj Saini, and Dushyant Kumar have worked on design and analysis of composite leaf spring for light vehicles. In this work, they consider passenger vehicle with ten-leaf steel spring for analysis of stress and deflection by using ANSYS 9 software. The aim is to compare the stresses and weight savings of composite leaf spring with that of steel leaf spring. The materials were selected E-glass/epoxy, carbon epoxy and graphite epoxy which is use against conventional steel. The design and the number of leaves for both steel leaf spring and composite leaf springs are considered to be the same. They consider design constraints were stresses and deflections. From the results it was found that there is a maximum displacement of 10.16mm in the steel leaf spring and the matching displacements in E-glass/epoxy, Graphite epoxy, and Carbon epoxy are 15 mm, mm and mm. From the static analysis results, the von-mises stress in the steel is MPa and the von-mises stress in Eglass epoxy, Graphite epoxy and Carbon epoxy is MPa, MPa and MPa was exiting respectively. A comparative study has been made between steel IJRTI International Journal for Research Trends and Innovation ( 175

2 and composite leaf spring with respect to strength and weight. Composite mono leaf spring reduces the weight by 81.22% for E- Glass/epoxy, 91.95% for Graphite epoxy, and % for Carbon epoxy over conventional leaf spring. [2] 3. MODELING OF BOTH LEAF SPRINGS Basic data of Force Motors Trax Cruiser leaf spring: Total length of the spring (Eye to Eye) = 1250 mm No. of full length leaves (nf) = 02 No. of graduated leaves (ng) = 04 Thickness of leaf (t ) = 7 mm Width of the leaf spring (b) = 60 mm Young s modulus (E)= 2x105 N/mm2 Central band 110 mm wide (Ineffective length) Tensile strength = N/mm2 Yield strength = 1800 N/mm2 Total load = 2850 Kg BHN = HB with hardened and tempered Basic requirement of load Maximum capacity = 2850 Kg = 2850 x 10 = N Force Motors Trax Cruiser is equipped with 4 nos. of semi elliptical leaf spring, So load acting on the leaf spring assembly = = 7125 N Calculation of the load and effective length of leaf spring 2 W = 7125 N W = W = N Effective Length of the spring, 2 L = 2 L ı 1 2 L = /3 (110) 2 L = L = / 2 L = mm Bending stress generated in the leaf spring is as under : σb = N/mm2 Deflection generated in the assembly of leaf spring is as under: IJRTI International Journal for Research Trends and Innovation ( 176

3 Figure 1 Sketch of master leaf Figure 2 3D model of master leaf Properties of steel material Parameter Material selected Young s modulus Values 50Cr1V23 2*10^5 MPa Poisson s ratio 0.3 BHN Tensile strength ultimate Tensile strength yield Density 2000 MPa 1800 MPa 7850 Kg/m3 Table 1 Properties of steel material Table 2 Properties of composite material: Sr No. Properties AFRP CFRP (Carbon) Graphite epoxy (FRP) 1 E X (MPa) E Y (MPa) E Z (MPa) PR XY PR YZ PR ZX G XY (MPa) G YZ (MPa) G ZX (MPa) ρ (kg/mm³) IJRTI International Journal for Research Trends and Innovation ( 177

4 4. STATIC ANALYSIS OF STEEL & COMPOSITE LEAF SPRING Create meshing of leaf spring. Meshing is the process which allows your geometry is spatially discredited into elements and nodes. This mesh along with material properties is used to mathematically represent the stiffness and mass distribution of the structure. The mesh has been generated automatically. The default element size is determined based on a number of factors including the overall model size, the proximity of other topologies, body curvature, and the complexity of the feature. As shown in figure 4.7 Number of elements used are 906 & and number of nodes used are Figure 3 Meshed model of leaf spring Apply boundary condition Boundary condition one end remote displacement for component X fixed, Y Free and Z fixed and rotation Z free, X and Y fixed and other end remote displacement for component X, Y and Z fixed and rotation Z free, X and Y fixed. Loading conditions involves applying a load upper side a centre of the bottom leaf spring. Define force Figure 4 Define force Define displacement constrain. Figure 5 Define displacements constrain at one end Figure 6 Define displacements constrain at another end IJRTI International Journal for Research Trends and Innovation ( 178

5 5. RESULT ANALTSIS OF STEEL LEAF SPRING Static structural analysis for bending stress and deflection as shown figures respectively Figure 7 Maximum deflection Fig 8 Von-misses stress contour Table 3 Analysis results of steel leaf spring Parameters Analytical Static analysis Percentage results Results variation Von-misses stress (MPa) % Maximum deflection (mm) % Table 3 Comparison of analytical and analysis result for steel leaf spring Figure 9 Deformation countor of CFRP composite leaf spring Figure 10 Stress countor of CFRP composite leaf spring Figure 11 Deformation countor of AFRP composite leaf spring Figure 12 Stress countor of AFRP composite leaf spring IJRTI International Journal for Research Trends and Innovation ( 179

6 Fig.13Deformation countor of Graphite Epoxy composite leaf spring Fig.14 Stress countor of Graphite Epoxy composite leaf spring Table 4 Analysis results of composite leaf spring Materials Displaceme nts Displaceme nts Stress (MPa) Weigh t (Kg) analytical (mm) simulation (mm) Steel CFRP AFRP Graphite epoxy OPTIMIZATION OF COMPOSITE LEAF SPRING In this work the thickness of original leaf spring reduced by 1mm from each spring. The results of optimize leaf spring are: Figure 15 deformation countor of CFRP composite leaf spring spring Figure Stress countor of CFRP composite leaf Figure 17 Deformation countor of AFRP composite leaf spring Figure 18 Stress countor of AFRP composite leaf spring IJRTI International Journal for Research Trends and Innovation ( 180

7 Figure 19 Deformation countor of Graphite Epoxy composite leaf spring Fig.14 Stress countor of Graphite Epoxy composite leaf spring Table 4 Analysis results of optimized composite leaf spring Materials Displaceme Stress (MPa) Weight (Kg) nts simulation (mm) CFRP AFRP Graphite epoxy CONCLUSION In the present research work a comparative study has been made of steel and GFRP, AFRP, CFRP. Under static loading condition Deflection and stresses of CFRP composite leaf spring are found with great difference. As well as the optimization analysis perform to optimize the composite leaf spring by reducing 1mm thickness of each leaf spring. The results are greatest at graphite epoxy and in weight reduction. REFERENCES [1]. V L Narayana (2012), Design and Analysis Of Mono Composite Leaf Spring For Suspension in Automobiles, Int. J. Eng. Res. & Tech., 1. [2]. B Mehdi and B Majid (2012), Optimization of Steel Helical Spring by Composite Spring, Int. J. Multidisciplinary Sci. Engg., 3, 6. [3]. M K Alwan, Q A Hama and M A Tariq (2011), The Polymer Composite Beam Reinforced by Natural Jute Fiber, Engg. Tech. [4]. Pankaj Saini¹, Ashish Goel², Dushyant Kumar³ ¹ ² ³B. Tech 4th Year Student, Department of ME, Moradabad Institute of Technology, Moradabad, Uttar Pradesh, INDIA, Design and analysis of composite leaf spring for light vehicles International Journal of Innovative Research in Science, Engineering and Technology. [5]. Sagar B Mahajan1, Prof.M.C.Swami2, Permeshwar Patil3 Design and Analysis of Mono Composite Leaf Spring by Varying Thickness using FEA IOSR Journal of Mechanical and Civil Engineering. [6]. Y N V Santhosh Kumar and M Vimal Teja (2012), Design and Analysis of Composite Leaf Spring, Int. J. Mech. Ind. Engg. [7]. Pozhilarasu1* and T Parameshwaran Pillai1, Corresponding Author: V Pozhilarasu pozhilarasu@gmail.com Performance analysis of steel leaf spring with composite leaf spring and fabrication of composite leaf spring,int. J. Engg. Res. & Sci [8] William D. callaster material science and engineering [9]. Parkhe Ravindra, Mhaske Raman, Belkar Sanjay, Modeling and Analysis of Carbon Fiber Epoxy Based Leaf Spring under the Static Load Condition by Using FEA International Journal of Emerging Science and Engineering. [10]. Jadhav Mahesh V, Zoman Digambar B, Y R Kharde, R R Kharde Performance Analysis of Two Mono Leaf Spring Used For Maruti 800 Vehicle,International Journal of Innovative Technology and Exploring Engineering. [11]. Ghodake A. P.*, Patil K.N. Department of Mechanical Engineering, SND COE & RC Yeola, Nashik, India, Analysis of Steel and Composite Leaf Spring for Vehicle, IOSR Journal of Mechanical and Civil Engineering. [12]. Nisar S. Shaikh, S.M. Rajmane, Modelling and Analysis of Suspension System of TATA SUMO by using Composite Material under the Static Load Condition by using FEA, International Journal of Engineering and Advanced Technology. IJRTI International Journal for Research Trends and Innovation ( 181