Design and Analysis of Composite Leaf Spring for Prescribed Stiffness

Size: px

Start display at page:

Download "Design and Analysis of Composite Leaf Spring for Prescribed Stiffness"

Drusilla Garrison
6 years ago
Views:

ISSN 2395-1621 Design and Analysis of Composite Leaf Spring for Prescribed Stiffness #1 S. B. Patil, #2 Dr. R. J. Patil 1 sagardesign05@gmail.com 1 rupesh1002001@yahoo.com #1 P.

1 ISSN Design and Analysis of Composite Leaf Spring for Prescribed Stiffness #1 S. B. Patil, #2 Dr. R. J. Patil 1 sagardesign05@gmail.com 1 rupesh @yahoo.com #1 P. G Student - Department of Mechanical Engineering, D. Y. Patil Institute of Engineering and Technology Talegaon, Savitribai Phule PuneUniversity, Pune, Maharashtra, India. #2 Principal - D. Y. Patil Institute of Engineering and Technology Talegaon, Savitribai Phule PuneUniversity, Pune, Maharashtra, India ABSTRACT The present work deals with optimal design and analysis of composite material leaf spring made up from E-Glass fiber. In this work the four-leaf steel spring used in the rear suspension system of light vehicle having vehicle weight 24 ton is studied. The objective of the present work is weight reduction of the suspension system for prescribed stiffness which results in better fuel economy at present fuel crises environment. For the analysis of the leaf spring performance parameters used are as stiffness, stress, strain energy storage capacity and fundamental natural frequency. The Ansys 15.0 software is used for the structural, optimization and modal analysis. After the structural analysis result of the steel leaf spring, Optimization is done by using design surface optimization for the thickness reduction using MOGA technique. The constant cross section mono-composite leaf spring is designed and analyzed for prescribed stiffness. The experimental validation is done by using Universal Testing Machine (UTM) and FFT analyzer. The comparison in between conventional and composite leaf spring shows the 50% weight reduction in the suspension system of a vehicle Keywords- Suspension leaf spring, Weight reduction, E-Glass fiber, Fuel economy, Structural and modal analysis, Stiffness, UTM and FFT analyzer ARTICLE INFO Article History Received:18 th November 2015 Received in revised form : 19 th November 2015 Accepted : 21 st November, 2015 Published online : 22 nd November 2015 I. INTRODUCTION Springs are crucial suspension elements on cars, necessary to minimize the vertical vibrations, impacts and bumps due to road irregularities and create comfortable ride. A leaf spring, especially the longitudinal type, is a reliable and persistent element in automotive suspension systems. These springs are usually formed by stacking leafs of steel, in progressively longer lengths on top of each other, so that the spring is thick in the middle to resist bending and thin at the ends where it attaches to the body. A leaf spring should support various kinds of external forces, but the most important task is to resist the variable vertical forces. In this paper efforts have been made to present use of E-Glass composite materials for suspension leaf spring. Semi elliptic leaf springs are almost universally used for rear suspension in light and heavy vehicles. The fig.1 shows semi elliptical type leaf spring. The spring consists of a number of blades called leaves and with different lengths. The lengthiest leave has eyes on its ends, called master leaf. The spring is supported on axle by means of U-bolt. One end is attached to frame by simple pin, while the other end is connected with shackle joint. The shackle joint gives flexible connection when the vehicle comes across a bump. Highly cambered springs provide a soft suspension but they increase the tendency to yaw. Flat springs reduce the tendency of pitching, when breaking or accelerating suddenly. Spring eyes are generally bushed with phosphor or bronze. But for cars and light transport vehicles rubber bushes are commonly used. The spring vibration is reduced by friction between two leaves but it produces the noise. Normally the steel industries are using SAE6150, SAE5160, SAE9254, 50Cr1V23 and 55Si2Mn90 steel for the manufacturing of leaf spring. But now a day's composite materials are getting more popular and preferred by an automotive industry.

Fig 2. Deformation Fig 1. Semielliptical Leaf Spring II.ANALYSIS OF THE CONVENTIONAL STEEL LEAF SPRING Fig 3.

1 Tensile Strength 1962 N/mm 2 2 Young's Modulus 2E5 N/mm 2 3 Total Length of the 1040 mm spring 4 Camber 150 mm 5 No. of full length leave 02 6 No. of graduated l leave 02 7 Thickness of leaf 6.

OPTIMIZATION For design of the composite leaf spring optimization of the conventional steel leaf spring is necessary.

2 Fig 2. Deformation Fig 1. Semielliptical Leaf Spring II.ANALYSIS OF THE CONVENTIONAL STEEL LEAF SPRING Fig 3. Von - Mises Stresses The specifications of the Steel (55Si2Mn90) leaf spring are as TABLE I SPECIFICATIONS OF THE STEEL LEAF SPRING Sr. Parameter Value No. 1 Tensile Strength 1962 N/mm 2 2 Young's Modulus 2E5 N/mm 2 3 Total Length of the 1040 mm spring 4 Camber 150 mm 5 No. of full length leave 02 6 No. of graduated l leave 02 7 Thickness of leaf 6.5 mm 8 Width of leaf spring 50 mm 9 Maximum Load given 6000 N 10 Weight of the leaf spring Kg Fig 4.Strain Energy III. OPTIMIZATION For design of the composite leaf spring optimization of the conventional steel leaf spring is necessary. Mainly optimization is done for the weight reduction by achieving optimum thickness. The optimization results are obtained also for deflection and stress. In Ansys 15.0 software surface optimization is done by using multi-objective genetic algorithm (MOGA).The results obtained are as,. A. Ansys Results Structural analysis is a process to analyze a structural system to predict its responses and behaviours by using physical laws and mathematical equations. The main objective of structural analysis is to determine internal forces, stresses and deformations of structures under various load effects. Fig 5. Optimization

spring N/mm 2 Fig 6. Optimum Deflection 8 Mass density of the material (ρ ) 9 Weight of the leaf spring 10 Tensile strength of the material 11 Compressive strength of the material 2 x 10-9 kg/mm 3 5.

3 spring N/mm 2 Fig 6. Optimum Deflection 8 Mass density of the material (ρ ) 9 Weight of the leaf spring 10 Tensile strength of the material 11 Compressive strength of the material 2 x 10-9 kg/mm kg 900 MPa 450 MPa A. Optimal Analysis of the Constant Cross Section Composite Leaf Spring Fig 7. Optimum Thickness Fig 9. Deformation Fig 8. Optimum Stresses Fig 10. Von - Mises Stresses IV. Analysis of composite leaf spring The specifications of the composite leaf spring are as TABLE II Specifications ofthe Composite Leaf Spring Sr. No. Parameter Value 1 Total Length of the 1040 mm spring 2 Free Camber 150 mm 3 No. of full length leave 01 4 Thickness of leaf 15 mm 5 Width of leaf spring 65 mm 6 Maximum Load given 6000 N on spring 7 Young s Modulus of the Fig 11. Strain Energy B. Modal Analysis of the Constant Cross Section Composite Leaf Spring Modal analysis is used to find natural frequency of the vibrating body to avoid the resonance within the operating frequency range.

Fig. 12 Modal Analysis of Steel Leaf Spring Fig. 15Natural Frequency Test VI.RESULTS Fig.

EXPERIMENTAL INVESTIGATION For experimental validation of the deflection, we have used Universal

The testing is done by fabricating the required fixture, in this boundary conditions used are as one

TABLE III Comparison Steel Composite Paramet ers F EA Experimen tal F EA Experimen tal Deflectio n (mm)

4 Fig. 12 Modal Analysis of Steel Leaf Spring Fig. 15Natural Frequency Test VI.RESULTS Fig. 13 Modal Analysis of Composite Leaf Spring V.EXPERIMENTAL INVESTIGATION For experimental validation of the deflection, we have used Universal Testing Machine. The testing is done by fabricating the required fixture, in this boundary conditions used are as one end of the leaf spring is being fixed and other end is free to move in the longitudinal direction. TABLE III Comparison Steel Composite Paramet ers F EA Experimen tal F EA Experimen tal Deflectio n (mm) Stiffness (N/mm) Von - Mises Stress (Mpa) Modal Analysis (Hz) 4 7 Fig. 14Universal Testing Machine The vibration testing is done for the fundamental natural frequency by using FFT analyzer with similar boundary conditions.

Fig.19 Frequency domain graph for Composite leaf spring Fig.16Load Vs Deflection Graph for Steel Leaf Spring Fig.20Comparison Fig.17Load Vs Deflection Graph for Composite Leaf Spring Fig.

CONCLUSION From the study it can be concluded that, In the past the automotive industry has used isotropic materials such as steels, aluminum and plastics when designing structural components.

5 Fig.19 Frequency domain graph for Composite leaf spring Fig.16Load Vs Deflection Graph for Steel Leaf Spring Fig.20Comparison Fig.17Load Vs Deflection Graph for Composite Leaf Spring Fig.18 Frequency domain graph for Steel leaf spring VII.CONCLUSION From the study it can be concluded that, In the past the automotive industry has used isotropic materials such as steels, aluminum and plastics when designing structural components. It has been observed that the automotive industry is greatly interested in the use of composite materials by replacing current steel material. From the results we can conclude that: Reduction in unsprung weight is possible due to use of composite material for fabrication of leaf spring. Almost 50% weight reduction is done. Composite leaf spring does not gets rusted, so the performance will not get reduced after prolong use. The ultimate tensile strength of the composite leaf spring more than that of conventional leaf spring ensuring good mechanical properties. Stresses generated in the composite leaf spring are much lower than that of conventional one. Fundamental natural frequency of the composite leaf spring is more than road vibrations and also conventional steel. Stiffness of the composite leaf spring is nearly same as that of conventional steel leaf spring, so we can replace conventional one by composite ACKNOWLEDGEMENT I wish to express thanks to my guide Dr. Patil R. J Principal D. Y. Patil Institute of Engineering and Technology for his support. I am thankful to our ME coordinator Prof.

6 Sonawane P. R for his kind support and providing all facilities and academic environment for my project work. My profound thanks to Prof. Bhor S. K Head of the Department of Mechanical Engineering for his invaluable advice and constant encouragement to complete this seminar report in a successful manner. I would also like to thanks to Mr. Dipak Pawar owner of ARC Industries Ichalkaranji for his valuable contribution in developing the E - Glass composite leaf spring REFRENCES [1] Mahmood M. Shokrieh, Davood Rezaei. "Analysis and optimization of a composite leaf spring", Composite Structures, 2003, pp [2] H. A. Al-Qureshi."Automobile Leaf Spring from Composite materials''. Journal of materials processing technology 118,2001, pp [3] Abdul Rahim Abu Talib, Aidy Ali, G. Goudah, Nur Azida Che Lahb, A.F. Golestaneh. ''Developing a composite based elliptic spring for automotive applications''. Materials and Design 31, 2010, pp [4] C. Subramanian, S. Senthilvelan. ''Effect of reinforced fiber length on the joint performance of thermoplastic leaf spring''. Materials and Design 31, 2010, pp [5] Ivo Cerny, Rayner M. Mayer. ''Fatigue of selected GRP composite components and joints with damage evaluation''. Composite Structures 94, 2012, pp [6] E. Mahdi, O.M.S. Alkoles, A.M.S. Hamouda, B.B. Sahari, R. Yonus,G.Goudah. ''Light composite elliptic springs for vehicle suspension''. Composite Structures 75, 2006, pp [7] Dipendra Kumar Roya and Kashi Nath Sahab. ''Nonlinear Analysis of Leaf Springs of Functionally Graded Materials''. Procedia Engineering 51, 2013, pp [8] Jiashi Wang, Zaike Li and Qibin Jiang. ''The Analysis of Composite Leaf Spring by Finite Element Method and Experimental Measurements'' / _74,Springer-Verlag Berlin Heidelberg, 2013, pp [9] V Sampath, S Vinodh Kumar, P Baskar. ''Analysis of leaf spring with variable thickness for composite materials''. International Journal for Technological Research in Engineering Volume 1, Issue 9, 2014 pp [10] M.Venkatesan, Helmen Devaraj. ''Design and analysis of composite leaf spring in light vehicle ''.International Journal of Modern Engineering Research (IJMER) Vol.2, Issue.1, 2012, pp [11] Ravi Kumar V, R. Lalitha Narayana. Ch. Srinivas. ''Analysis of Natural Fiber Composite Leaf Spring''. International Journal of Latest Trends in Engineering and Technology (IJLTET) Vol. 3, 2013, pp [12] U. S. Ramakanth & K. Sowjanya. ''Design and analysis of automotive multi-leaf springs using composite materials''. International Journal of Mechanical Production Engineering Research and Development (IJMPERD) ISSN Vol. 3, Issue 1, 2013 pp [13] 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 (IJESE) ISSN: , Volume-2, Issue-4, 2014, pp [14] Pankaj Saini, Ashish Goel, Dushyant Kumar. ''Design and analysis of composite leaf spring for light vehicles''. International Journal of Innovative Research in Science, Engineering and Technology Vol. 2, Issue 5, 2013, pp [15] Ganesh, Gembiram.M, Elayaraja.R, Saravanan.R, Murali.K. ''Design and Analysis of Multi Leaf Springs Using Composite Materials''. International journal for research in applied science and engineering technology (ijraset) vol. 2 issue IV, 2014, pp [16] S.Rajesh and G.B.Bhaskar. ''Experimental Investigation on Laminated Composite Leaf springs Subjected to Cyclic Loading''. International Journal of Engineering and Technology (IJET), Vol. 6 No 1, 2014, pp [17] Pengbo Wang, Chongliang Zhang and Yongquan Liu. "Simulation and Design of Leaf Spring Characteristics'' SAE International, [18] Murathan Soner, Metin Tanoglu, Nilay Guven, Mustafa Karaagac. ''Design and Fatigue Life Comparison of Steel andcomposite Leaf Spring''.SAE International, [19] Murathan Soner, Gorkem Ozcelik, Ciler Senocak, Seray Goksel Tokgonul, Tolga Erdogus,Mustafa Karaagac and Ahmet Kanbolat. ''Leaf Spring Design Considering Natural FrequencyCalculations Based On NVH''.SAE International, 2013.

DESIGN AND DEVELOPMENT OF COMPOSITE LEAF SPRING - REVIEW

DESIGN AND DEVELOPMENT OF COMPOSITE LEAF SPRING - REVIEW 1, Asst. Prof. Qaimi M.G.S 2 1ME Student, arunpawar7@gmail.com 2 Assistant Professor,qmudassara@gmail.com Mechanical Department, D.Y.P. Institute