Fem of Double Wishbone Suspension
7
IOSR Journal o f Mechanical and Civil Engineer ing (IOSR-JMCE) e-ISSN: 2278-168 4,p-ISS N: 2320-334X, Volume 7, Issue 2 (May. - Jun. 2013), PP 43-48 www.iosrjournals.org www.iosrjournals.org 43 | Page Experimental & Finite Element Analysis of Left Side Lower Wishbone Arm of Independent Suspension System Prof. A. M. Patil 1 , Prof. A.S. Todkar 2 , Prof. R. S .Mithari 3 , Prof. V. V. Patil 4 1234 Mechanical Engineer ing Department, T.K.I .E.T. Warananagar, Shivaji Uni versity, Tal. Panhala, Dist. Kolhapur, India. Abstr act : The Wishbone control arm is a type of independent suspension used in motor vehicles. The general function of control arms is to keep the wheels of a motor vehicle from uncontrollably swerving when the road conditions are not smooth. The control arm suspension normally consists of upper and lower arms. The upper and lower control arms have different structures based on the model and purpose of the vehicle. By many accounts, the lower control arm is the better shock absorber than the upper arm because of its position and load bearing capacities. It has an “A” shape on the bottom known as wishbone shape which carries most of the load from the shock received. The lower control arm t akes most of the impact that the road has on the wheels of the motor vehicle. It either stores that impact or sends it to the coils of the suspension depending on its shape. During t he actual working condition, the maximum l oad i s transferred from upper wishbone arm to t he lower arm which creates possibility of failure in the arm. Similarly, impact loading produces the bending which is not desirable. Hence it is essential to foc us on the stress strain analysis study of lower wishbone arm to improve and modify the existing design. The present study w ill contribute in this problem by using finite elemen t a nalysis approach. Keywords – Lower W ishbone Arm, Independent susp ension, Finite Element Analysis, A NSYS software. I. Introduction The Lower Wishbone is also called A-arm. Wishbones can be used in an all wheel independent suspension setup. Read on to kn ow more a wishbone has two mountings on the chassis of a car and one to locate the wheel it is connected to. Because two rods are used on the two mounting points it is called a double wishbone setup. Double wishbones provide more stability to wheel movements at high speeds which reduces camber angle as the wheel moves up and down over uneven surfaces. Wishbones can be very easily adjusted as every joint can be tweaked for optimal wheel movement. In automobiles, a double wishbone (or upper and lower A-arm) suspension is an independent suspension design using two (occasionally parallel) wishbone- shaped arms to locate the wheel. During the actual working condition, the maximum load is transferred from upper wishbone arm to the lower arm which is possibility of failure & bending of lower wishbone arm at the ball joint location as well as control arm because of high impact load by produces road condition which is not desirable. Hence it is essential to focus on the stress strain analysis study of lower wishbone arm to improve and modify the existing design. Also current conventional material (mild steel) is r eplaced by composite materials (Carbon fiber polymer). The current car used double wishbone suspension arm built from mild steel and it can affect the weight of vehicle. Therefore, in order to make new improvement and ove rcome this problem, a study about car suspension has been carry away and it involving composite material. Carbon fiber polymer has proven for it strength beyond the steel and provide less weight. By apply this fact; the study about car suspension in composite form has taken place. II. Solid Modeling Of Lower Wishbone Arm In Catia V5 R17 To carry out FEM analysis of any component, the solid model of the same is essential. It is also called body i n white. So the solid model of Independent Suspension is require and th is can be done in special CAD package like CATIA V5 R17.
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IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE)e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 7, Issue 2 (May. - Jun. 2013), PP 43-48www.iosrjournals.org
www.iosrjournals.org 43 | Page
Experimental & Finite Element Analysis of Left Side Lower
Wishbone Arm of Independent Suspension System
Prof. A. M. Patil1, Prof. A.S. Todkar
2, Prof. R. S .Mithari
3, Prof. V. V. Patil
4
1234 Mechanical Engineering Department, T.K.I.E.T. Warananagar, Shivaji University,
Tal. Panhala, Dist. Kolhapur, India.
Abstract : The Wishbone control arm is a type of independent suspension used in motor vehicles. The general
function of control arms is to keep the wheels of a motor vehicle from uncontrollably swerving when the roadconditions are not smooth. The control arm suspension normally consists of upper and lower arms. The upperand lower control arms have different structures based on the model and purpose of the vehicle. By manyaccounts, the lower control arm is the better shock absorber than the upper arm because of its position and load
bearing capacities. It has an “A” shape on the bottom known as wishbone shape which carries most of the load from the shock received. The lower control arm takes most of the impact that the road has on the wheels of the
motor vehicle. It either stores that impact or sends it to the coils of the suspension depending on its shape. During the actual working condition, the maximum load is transferred from upper wishbone arm to the lowerarm which creates possibility of failure in the arm. Similarly, impact loading produces the bending which is notdesirable. Hence it is essential to focus on the stress strain analysis study of lower wishbone arm to improve andmodify the existing design. The present study will contribute in this problem by using finite element analysisapproach.
Keywords – Lower Wishbone Arm, Independent suspension, Finite Element Analysis, ANSYS software.
I. Introduction The Lower Wishbone is also called A-arm. Wishbones can be used in an all wheel independent
suspension setup. Read on to know more a wishbone has two mountings on the chassis of a car and one to locatethe wheel it is connected to. Because two rods are used on the two mounting points it is called a doublewishbone setup. Double wishbones provide more stability to wheel movements at high speeds which reducescamber angle as the wheel moves up and down over uneven surfaces. Wishbones can be very easily adjusted as
every joint can be tweaked for optimal wheel movement. In automobiles, a double wishbone (or upper andlower A-arm) suspension is an independent suspension design using two (occasionally parallel) wishbone-shaped arms to locate the wheel.
During the actual working condition, the maximum load is transferred from upper wishbone arm to thelower arm which is possibility of failure & bending of lower wishbone arm at the ball joint location as well ascontrol arm because of high impact load by produces road condition which is not desirable. Hence it is essentialto focus on the stress strain analysis study of lower wishbone arm to improve and modify the existing design.
Also current conventional material (mild steel) is replaced by composite materials (Carbon fiber polymer).The current car used double wishbone suspension arm built from mild steel and it can affect the weight ofvehicle. Therefore, in order to make new improvement and overcome this problem, a study about car suspensionhas been carry away and it involving composite material. Carbon fiber polymer has proven for it strength beyond the steel and provide less weight. By apply this fact; the study about car suspension in composite formhas taken place.
II. Solid Modeling Of Lower Wishbone Arm In Catia V5 R17To carry out FEM analysis of any component, the solid model of the same is essential. It is also called
body in white. So the solid model of Independent Suspension is require and this can be done in special CAD package like CATIA V5 R17.
8/11/2019 Fem of Double Wishbone Suspension
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Experimental & Finite Element Analysis of Left Side Lower Wishbone Arm of Independent Suspension
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Fig. 1.1 CATIA Modeling of Lower Wishbone Arm.
III. Stress Analysis Procedure In Fea:-
The load applied on Lower Wishbone Arm is W1 = 4900N. Then stress analysis by ANASYS Software the
results are given by following fig.
Fig. 1.2 Stress in Lower Wishbone Arm in structural steel & composite material.
GRAPHICAL REPRESENTATION OF STRESS AT DIFFERENT LOAD CONDITIONS ISGIVEN BY.
SR.
NO.
LOAD (N) STRUCTURAL STEEL (Pa) COMPOSITE MATERIAL
(Pa)
1. 4900 5.1421e8 6.3719e8
2. 5500 5.7717e8 7.1522e8
3. 6000 6.2964e8 7.8024e8
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Experimental & Finite Element Analysis of Left Side Lower Wishbone Arm of Independent Suspension
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STRESS (108PA) VS LOAD (N) CURVE:-
The load applied on Lower Wishbone Arm is W1 = 4900N. Then maximum & minimum strain values are
found by ANASYS the results are given by following fig.
Fig. 1.3 Strain in Lower Wishbone Arm in structural steel & composite material.
GRAPHICAL REPRESENTATION OF STRAIN AT DIFFERENT LOAD CONDITIONS IS
GIVEN BY.
SR. NO. LOAD (N) STRUCTURAL STEEL COMPOSITE MATERIAL
1. 4900 0.002571 0.12804
2. 5500 0.002885 0.14372
3. 6000 0.0031482 0.15679
STRAIN VS LOAD (N) CURVE:-
4.5
5
5.5
6
6.5
7
7.5
8
4200 5200 6200
S t r e s s 1 0 8 P a
Load N
Sturctural Steel
(Pa)
Composite
Material (Pa)
0
0.05
0.1
0.15
0.2
4200 4700 5200 5700 6200
S t r a i n
Load (N)
Composite
Material
Sturctural
Steel
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Experimental & Finite Element Analysis of Left Side Lower Wishbone Arm of Independent Suspension
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The load applied on Lower Wishbone Arm is W1 = 4900N. Then maximum & minimum total deformation
values are found by ANASYS the results are given by following fig.
Fig. 1.4 Total deformation in Lower Wishbone Arm in structural steel & composite material.
GRAPHICAL REPRESENTATION OF TOTAL DEFORMATION AT DIFFERENT LOADCONDITIONS IS GIVEN BY.
SR. NO. LOAD (N) STRUCTURAL STEEL(m) COMPOSITE MATERIAL (m)
1. 4900 0.0056037 0.24123
2. 5500 0.0062898 0.27076
3. 6000 0.0068616 0.29538
GRAPH OF TOTAL DEFORMATION (M) VS LOAD (N)
Natural Frequency measurement by FFT Analyzer:Frequency response Function of Independent Suspension Link gives the natural frequency at the peaks with
corresponding amplitude at respective location of accelerometer on the Link.
Fig.1.5 frequency graph at position near front control arm
0
0.03
0.06
0.09
0.12
0.15
0.18
0.21
0.24
0.27
0.3
4600 4900 5200 5500 5800 6100
T o t a l D e f o r m
a t i o n ( m )
Load (N)
Composite
Material (m)Sturctural Steel
(m)
FRIST POSITION FREQUENCY GRAPH
-100
-80
-60
-40
-20
0
20
0 500 1000 1500 2000 2500 3000
FREQUENCY
A C C E L R A T I O N
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Experimental & Finite Element Analysis of Left Side Lower Wishbone Arm of Independent Suspension
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Fig.1.6 frequency graph at position near rear control arm.
Fig.1.7 frequency graph at position near wheel centre
Fig.1.8 frequency graph at all three position near front control arm
IV. Comparisons of Natural frequencies by FEM and Experimental Method.In the present study modal analysis of Independent Suspension Link is done by Fem as well as
Experimental method. Now to obtain the validation for FEM result we can compare those with the experimentalresults. The below table gives the comparison of natural frequencies obtained by Fem and Exponential methodalong with percentage difference at error obtained for Independent Link.
SECOND POSITION FREQUENCY
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0 500 1000 1500 2000 2500 3000
FREQUENCY
A C C E L R A T I O N
THIRD POSITION FREQUENCY GRAPH
-80
-70
-60
-50
-40
-30
-20
-10
0
0 500 1000 1500 2000 2500 3000
FREQUEN CY
A C C E L R A T I O N
Series1
FREQUENY GRAPH OF ALL THREE POSITION
-100
-80
-60
-40
-20
0
20
0 500 1000 1500 2000 2500 3000
FREQUENCY
A C C E L R A T I O N
FRIST POSITION SECOND POSITION THIRD POSITION
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Experimental & Finite Element Analysis of Left Side Lower Wishbone Arm of Independent Suspension
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Sr.
No.
Natural Frequency by ANSYS
in Hz
Experimental Natural
Frequency in Hz
Percentage deviation
1 577.76 481.125 16.72
2 694.05 596.875 13.99
3 826.55 793.75 3.96
4 842.33 859.375-2.02
5 1023.7 1071.875 -4.7
6 1185.1 1184.375 0.0061
7 1245.9 1378.125 -1
8 1329.3 1428.125 -7.38
9 1363.6 1490.46 -9.3
10 1485.1 1556 -4.7
Table 7.3: Comparison of Natural Frequencies by FEM and Experimental Method.
Fig.1.9 Comparison of Natural Frequencies Remark: The Four channel F.F.T. Analyzer is used for experimentation. The average percentage deviation inexperimental natural frequencies and natural frequencies by ANSYS software are found to be 6.3756 %.
IV.
Conclusion Under the static load conditions deflection and stresses of steel lower wishbone arm and composite
lower wishbone arm are found with the great difference. Carbon fiber suspension control arms that meet thesame static requirements of the steel ones they replace. Deflection of Composite lower wishbone arm is high as
compared to steel lower wishbone arm with the same loading condition. The redesigned suspension armsachieve an average weight saving of 27% with respect to the baseline steel arms. The natural frequency ofcomposite material lower wishbone arm is higher than steel wishbone arm.
AcknowledgementsI am thankful to my Co-author Prof. A .S. Todkar and Prof. R. S. Mithari in Mechanical Engineering Dept.,
TKIET, Warananagar, for their encouragement and support to carry out this work.
References[1] Hazem Ali Attia, „Dynamic modelling of the double wishbone motor -vehicle suspension system.‟ European Journal of Mechanics
A/Solids 21 (2002) 167 – 174.
[2] J.C. Fauroux, B.C. Bouzgarrou, „Dynamic obstacle-crossing of a wheeled rover with double wishbone su spension.‟ French Institute
for Advanced Mechanics (IFMA), EA3867, FR TIMS / CNRS 2856.
[3] J. S. Hwang, S. R. Kim and S. Y. Han, ‘Kinematic design of a double wishbone type front suspension mechanism using multi-
objective optimization‟,5th Australasian C ongress on Applied Mechanics‟, ACAM 2007,10-12 December 2007, Brisbane, Australia.
[4] V.V. Jagirdar, M.S. Dadar, and V.P. Sulakhe, „Wishbone Structure for Front Independent Suspension of a Military Truck‟, Defence
Science Journal, Vol. 60, No. 2, March 2010, page- 178-183.
[5] G. Fourlaris, R. Ellwood, T.B. Jones, „The reliability of test results from simple test samples in predicting the fatigue per formance of
automotive components‟ Materials and Design 28 (2007) 1198 – 121.
[6] Jihui Liang, Lili Xin, „ Simulation analysis and optimization design of front suspension based on ADAMS‟ MECHANIKA. 2012
Volume 18(3): 337-340.
[7] Thomas Uchida ,John McPhee, „Driving simulator with double-wishbone suspension using efficient block-triangularized kinematic
equations‟ Department of Systems Design Engineering, University of Waterloo , 200 University Avenue West, Waterloo, Ontario, N2L
3G1, Canada.
[8] Hemim M.M., Rahman, M.M and Omar R. M. „ Dynamic analysis of vehicle arm based on finite element approach‟, Journal of
Advanced Science and Engineering Research (2011) 124-136.[9] Chandrupatla, T. R. Belegundu, A.D. “Introduction to Finite Elements in Engineering”, Prentice-Hall of India Private Limited, New
Delhi 1999.
0
200
400
600
800
1000
1200
1400
1600
0 1 2 3 4 5 6 7 8 9 10 11 12
F r e q u e n c y i n
H z
Natural Frequency
by ANSYS in Hz
Experimental
Natural Frequency
in Hz
