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Vol-3 Issue-5 2017 IJARIIE-ISSN(O)-2395-4396
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DESIGN & ANALYSIS OF MONO LEAF
SPRING
Miss. Payal S. Tajanpure1 Dr. S. N. Shelke2
1 P. G. Student, in Mechanical (Design) Engineering Department, R. H. SAPAT COE, Nashik, Maharashtra, India.
2 Professor, in Mechanical Engineering Department, R. H. SAPAT COE, Nashik, Maharashtra, India.
ABSTRACT
The fuel efficiency and emission gas regulation of automobiles are two important issues now a day. The best way to increase
the fuel efficiency is to reduce the weight of the automobile. This project work focus on weight optimization of mono leaf
spring used in the automotive vehicles. The goal of the present work is to design, analyze, fabricate and testing of
unidirectional E-Glass Fiber / Epoxy / Kevlar mono composite leaf spring as per ASTM standards. Determine through
structural analysis the Load vs. Deflection of Composite Leaf Spring. Initially the compression test is carried out to
determine the deflection at the design load. Spring is chemically tested, its composition is found out and it found that the
spring is made up of chromium vanadium EN-47 steel. Further the analysis is carried out for the composite spring of same
dimensions to achieve the stated objective.
Keywords- Composite leaf spring, Deflection, analysis.
1. INTRODUCTION
Now a day the fuel efficiency and emission gas regulation of automobiles are two important issues. To fulfill this problem the
automobile industries are trying to make new vehicle which can provide high efficiency with low cost. The best way to
increase the fuel efficiency is to reduce the weight of the automobile. The weight reduction can be achieved primarily by the
introduction of better material, design optimization and better manufacturing processes. The achievement of weight reduction
with adequate improvement of mechanical properties has made composite a very good replacement material for conventional
steel. In automobile car out of many components one of the components of automobile accounts for 10 to 20% of unsprung
weight. which can be easily replaced is leaf spring. A leaf spring is a simple form of spring, commonly used for the
suspension wheeled vehicles. The suspension of leaf spring is the area which needs to focus to improve the suspensions of the
vehicle for comfort ride. The suspension leaf spring is one of the potential items for weight reduction automobile as it
Fig.1: Mono leaf spring
2. LITERATURE SURVEY
Al-Qureshi presented a general study on the analysis, design and fabrication of composite leaf spring. A single leaf, variable
thickness spring of glass fiber reinforced plastic (GFRP) with similar mechanical and geometrical properties to the multi leaf
steel spring, was designed fabricated (molded and hoop wound) and tested. Comparison between the performance of the
GFRP and the multi leaf steel spring was presented. Shokrieh & Rezaei analyzed four leaf steel spring used in the rear
suspension system of light vehicles using the ANSYS V 5.4 software. The finite element results showing stresses and
deflections verified the existing analytical and experimental solutions. The objective was to obtain a spring with minimum
weight that is capable of carrying given static external forces without failure. Shankar and Vijayarangan described a low cost
fabrication of complete mono composite leaf spring and mono composite leaf spring with bonded end joints. A single leaf
with variable thickness and width for constant cross sectional area of unidirectional GFRP with similar mechanical and
geometrical properties to the multi leaf spring, was designed, fabricated (hand-layup technique) and tested. The results
showed that an spring width decreases hyperbolically and thickness increases linearly from the spring eyes towards the axle
seat. Jadhao and Dalu described that the composite material has high strength to weight ratio, good corrosion resistance
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properties. The objective of present study was to replace material for leaf spring. The material selected was glass fiber
reinforced plastic (GFRP) and the polyester resin (NETPOL 1011) can be used which will reduce total cost of composite leaf
spring. The experiments were conducted on UTM and numerical analysis was done via (FEA) using ANSYS software. Result
shows that, the composite spring has stresses much lower than steel leaf spring and weight of composite spring was nearly
reduced up to 85% Abdul Rahim Abu Talib et al. have worked on developing a composite based elliptic spring for
automotive applications. The objective is to compare the load carrying capacity, fatigue behavior and weight savings of
composite leaf spring with that of steel leaf spring P They concluded that composite elliptical springs have better fatigue
behavior than the conventional steel leaf spring and weight reduction ratio is static load condition achieved. patunkar and
Dolas in their research paper discussed the analysis of composite mono leaf spring made of glass fiber reinforced plastic.
Then simulation was done for the composite spring of glass fiber under the same. From the above literature it can be observed
that there is need of experimental investigation of mono leaf spring for light duty/passenger vehicle. The conventional mono
leaf spring then can be replaced with the composite spring.
3. PROBLEM DEFINATION
This project work focus on weight optimization of mono leaf spring used in the automotive vehicles. The goal of the
present work is to design, analyze, fabricate and testing of unidirectional E-Glass Fiber/Epoxy/Kevlar mono composite leaf
spring.
3.1. Objective of Study
1. To develop a composite material fiber particulate for application of leaf spring.
2. To test the spring as per ASTM standards.
3. Determine through structural analysis the Load vs. Deflection of Composite Leaf Spring.
4. METHODOLOGY
In order to achieve desired objective. From the website of Maruti we have connected the data related to the maximum power
and speed which is used to find out the maximum load shared by each spring. In this work we are going to conduct test on the
rear mono leaf spring of Maruti Omni. In order to determine the deflection at the design load the spring is tested on the UTM.
From the Ansys we can determine total deformation in order to optimize in the existing leaf spring. Later on the composite
material is taken for fabrication of leaf spring.
5. LEAF SPRING CALCULATIONS FOR MARUTI OMNI
The Maruti Omni van is basically a Japanese commercial van that has been converted with some modification into a
passenger vehicle. Gross weight of Vehicle=Weight of vehicle +Weight of person
Omni 8 Seater has Weight of 800kg
The carrying capacity is 8(7+1)
Let the average weight of person is 70kg so 70*8=560kg
So Gross weight of Vehicle=800+560=1360Kg
Total weight acting downward=1360×9.81×1.5
Total weight=200012.4N=20000N
The Vehicle has 4 springs, two at front and 2 at rear.
So Weight on spring=20000/4=5000N
Fig 2: Experimental Setup
B. Chemical Testing
Component
C
Mn
Si
S
P
Cr
V
Percentage
0.45
0.75
0.24
0.018
0.016
0.97
0.16
TABLE 2: CHEMICAL COMPOSITION
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C. Hardness Testing
Hardness test is carried out which confirms hardness of 454/459HV-30(Hardness of 45/46HRC).From the above the
test the EN-47 Chromium vanadium spring steel confirms.
6. ANALYSIS
Fig. 3: Leaf spring modeled as Cantilever Beam Fig. 4: Meshing of Leaf Spring
Fig. 5: Deformation at 1000N Fig. 6: Deformation at 2000N
7. COMPOSITE LEAF SPRING
7.1 Fabrication of Composite Spring
For fabrication of composite leaf spring the pattern is required. The pattern required is made up of plywood. The dimensions of
pattern are calculated from the dimensions of the designed composite leaf spring.
1. Cutting of fibers: The fiber sheets of both carbon fiber an glass fiber are cut into dimensions 990mm×50.13mm.
2. Preparation of matrix: The matrix used is polyester. Polyester contains all the properties of resin, hardener and accelerator.
By using polyester the layers of fiber are stacked over one another.
3. Fabrication: The fiber sheets are layered one over another with the help of matrix. The sheet of carbon fiber over glass fiber is
layered. 24Hrs.time is required for setting of composite material.
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Fig. 7: Final Component
TABLE 2: LOAD VS DEFLECTION (MARUTI OMNI) TABLE 3: LOAD VS DEFLECTION (COMPOSITE)
8. ANALYSIS OF COMPOSITE MONO SUSPENSION SPRING
The analysis of newly fabricated composite mono suspension spring is carried out in ANSYS Workbench
Fig. 8: Geometry Fig. 9: Meshing of spring
Load (N)
Deflection(mm)
1000
13.10
1520
23.80
2000
36.90
2520
50.90
3000
64.60
3520
78.60
4000
95.80
4520
115
5000
131.40
Sr. No.
Load(N)
Deflection(mm)
1
1000
35.3
2
2000
70.6
3
2800
80.3
4
3000
101.44
5
3200
106.48
6
3600
136.69
7
4000
154.12
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Fig. 10: Deformation at 1000N Fig. 11: Deformation at 2000N
Fig. 12: Deformation at 3000N Fig. 13: Deformation at 4000N
9. RESULTS AND DISCUSSION
From the above experiment it can be observed that
1. Material for the current spring is chromium vanadium E-47 steel, the analytical and experimental modeling for which is carried
out successfully.
2. Composite with 70:30 combination of glass fiber is selected based on flexural strength and spring is manufactured of which is
2.9Kg as compared to 3.684 kg for conventional spring and 21.28%weightreduction is observed.
3. As compared to conventional spring more deflections is observed but good ductility is observed in new fabricated spring.
4. From the analytical and experimental analysis it is observed that the deformation for new material for same loading condition is
less as compared to conventional material so the composite material can be used for the automotive applications.
TABLE 4: Comparative Results (All Parameters)
10. VALIDATION
Sr.
No.
Composite Spring
Error
Percentage
Load
Deformation
Analytical
Deformation(mm)
1
1000
35.3
33.45
5.24
3
2000
70.6
66.91
5.22
3
3000
101.44
100.37
1.06
Sr.
No.
EN -47
Composite Spring
Load
Deformation
Expt. (mm)
Deformation
in Ansys(mm)
Bending
Stress(MPa)
Load
Deformation
Expt.(mm)
Deformation
in Ansys(mm)
Bending
Stress(MPa)
1
1000
13.10
34.48
833.94
1000
35.3
33.45
130.38
2
2000
36.90
68.96
1668.53
2000
70.6
66.91
260.77
3
3000
64.60
103.44
2502.81
3000
101.44
100.37
391.16
4
4000
95.80
137.92
3337.07
4000
154.12
133.83
521.55
5
5000
131.40
174.4
4171.34
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4
4000
154.12
133.83
13.14
Average Error
6.24
TABLE 5: Validation
Thus the analytical and experimental comparison is done which indicates 93.75% accuracy based on above results. Thus
composite material for the spring can be used for the automotive suspension application.
11. CONCLUSION
Thus this work focuses on the experimental investigation of mono suspension leaf spring of Maruti Omni which is
tested mechanically for compression test on UTM.
From the chemical test the chemical composition is determined which confirms the existing material for spring is
EN47 chromium vanadium steel.
With Hand layup method the composite spring carbon glass fibre is manufactured and tested successfully.
From the Analytical Analysis it is observed that the deformation for new composite leaf spring is less as compared
to conventional spring.
Thus the new material can be used in automotive suspension application.
12. ACKNOWLEDGMENT
I would like to be thankful to Prof. Dr. S. N. Shelke (M. E. coordinator and Project Guide, R. H. SAPAT COE, Nashik), Prof.
K.V. Chandratre (HOD, Mechanical department R. H. SAPAT COE ) and Dr .P.C. Kulkarni ( Principal, R. H. SAPAT
COE),all my teachers and my friends for their guidance.
6. REFERENCES
[1] H. A. Al-Qureshi, “Automobile leaf springs from composite materials”, Journal of Materials Processing
Technology, 118, 2001, 58-61.
[2] Mahmood M. Shokrieh, DavoodRezaei, “Analysis and optimization of a composite leaf spring”, Composite
Structures 60 (2003) 317325.
[3] I. Rajendran, S. Vijayarangan, “Optimal design of a composite leaf spring usinggenetic algorithms”, Computers and
Structures, 79, 2001, pp 1121-1129.
[4] K. K. Jadhao, DR. R. S. Dalu, “Experimental investigation & numerical analysis of composite leaf spring”,
International Journal of Engineering Science and Technology, Vol. 3, No. 6, 2011.
[5] Abdul Rahim Abu Talib, Aidy Ali, G. Goudah, Nur Azida Che Lah, A.F. Golestaneh, “Developing a composite
based elliptic spring for automotive applications”, Materials and Design, 31, 2010, pp 475–484.
[6] M. M. Patunkar, D. R. Dolas, “Modelling and Analysis of Composite Leaf Spring under the Static Load Condition
by using FEA”, International Journal of Mechanical & Industrial Engineering, Volume 1, Issue 1, 2011.
[7] Kumar Krishan, Aggarwal M.L, “Computer aided FEA comparison of mono steel and mono GRP leaf spring”,
International Journal of Advanced Engineering Research and Studies, Vol. I, Issue II, 2012, pp 155-158.
[8] N. P. Dhoshi, Prof. N. K. Ingole, Prof. U. D. Gulhane, “Analysis and modification of leaf spring of tractor trailer
using analytical and finite element method”, International Journal of Modern Engineering Research, Vol.1, Issue.2,
pp 719-722.
ResearchGate has not been able to resolve any citations for this publication.
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