Static structural analysis of suspension arm using finite element method

IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 07 | July-2015, Available @ http://www.ijret.org 402
STATIC STRUCTURAL ANALYSIS OF SUSPENSION ARM USING
FINITE ELEMENT METHOD
Jagwinder Singh1
, Siddhartha Saha2
1
Student, Mechanical Engineering, BBSBEC, Punjab, India
2
Assistant Professor, Mechanical Engineering, BBSBEC, Punjab, India
Abstract
The function of suspension system is to absorb vibrations due to rough terrains or road disturbances and to provide stability
under circumstances like accelerating, cornering, uneven road, braking, loading and unloading etc. Control arm is one of the
most important part of the suspension system, as it joins the steering knuckle to the vehicle frame. Also suspension arm is
responsible for up and down movement of wheels when hitting bumps. It is also designed to maximize the friction between tire
contacts, patch the road surface to provide vehicle stability under any circumstances. It can be seen in many types of the
suspensions like wishbone or double wishbone suspensions. Many times it is also called as A-type control arm. In this study
control arm was reverse engineered. Reverse engineering refers to the process of obtaining a CAD model from an existing
physical part. CAD model was prepared using CATIA v5 software and finite element analysis was done using ANSYS 14.5
software by importing the parasolid file to ANSYS. The model is subjected to loading and boundary conditions and then analyzed
using the FEA techniques. The static structural analysis was done to find out the stress, deformation and safety factor of
component. The model was meshed using 10-noded tetrahedral elements. Result obtained from the analysis were studied to check
whether the design is safe or not. In some cases the stresses becomes more than safe limit. In that case optimization approach is
carried out to increase the structural strength of the component. In this case maximum von-misses stress is 211 MPa which is
below the yield strength of the material.
Keywords – Suspension System, Control Arm, FEA analysis, Reverse Engineering
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1. INTRODUCTION
The lower suspension arm are connected to the vehicle
frame with bushing and permits the wheel to go up and
down in response to the road surface. Control arm is the
most crucial part of the suspensions system. It is made from
materials like steel, iron or aluminum. Suspension arm is
very important for the all vehicles on the road, if there is no
suspension arm in suspension system, then it is expected
that it can result in annoying vibrations and unwanted
driving irregularities that could sometimes lead to road
accidents like collisions with another car or obstruction on
the road. Suspension arm is one of the most important
component in the suspension system. It is fitted in various
types of the suspensions like Macpherson, wishbone or
double wishbone suspensions. During actual working
conditions the maximum load is transferred from tire to the
ball joint in Macpherson strut system and in double
wishbone maximum load is transferred from upper arm to
the lower arm which is responsible for the failure and
twisting of lower suspension arm at the ball joint locations
as well as control arm because of more impact load. Hence
it essential to focus on the stress and deformation study of
lower suspension arm to develop and the changes in existing
design. The FEA approach is used for analysis of a
suspension link for static and Von-Mises stress analysis of
lower suspension arm. Analysis is to be done considering
the Gross vehicle weight. As stress is higher than safe limit
or yield strength some geometric changes adopted in design
to make it safe.
2. OBJECTIVES
The aim of the project is to FEM analysis of lower arm.
Following are the main objectives of project-
 Manual reverse engineering of the suspension arm
 Making a 3D solid parametric model of suspension
link in CATIA software
 Meshing the model by 10 noded tetrahedral elements
in ANSYS
 Static analysis to find Von-Mises stresses
 Static analysis deformation plot in ANSYS
 If fails corrective actions for design improvement of
suspension link.
3. PROBLEM DEFINITION
Due to the many functions control arm is main part in
components of suspension system. As vehicle goes through
speed breaker, bumps etc. and many other kinds of forces
transmitted from the car wheels which are transferred to
control arm via ball joint assembly to the wheel. Force
values are mentioned in the load case. So in this study the
key concern is to discover the maximum stress section and
stress value in control arm and relate these values with
tensile yield strength of material.
4. METHODOLOGY
To solve the problem mentioned above we have used the
methodology. We have first manually reverse engineered

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the lower suspension arm with the help of special tools like
Vernier gauge, radius gauge and divider etc. All the
dimensions which are measured have been recorded on the
drawing. Now by taking the dimensions from the drawing
modelling of lower suspension arm is done in CATIA
software. After modelling the lower suspension arm, we
have import the IGES file to the ANSYS which is FEA
software by using this software we have to solve the
problem.
Further we have to mesh the model by using the 10 noded
tetrahedral elements. Tetra elements give improved results
as compared to other type of elements, therefore tetrahedral
elements were used. In further step we have to apply the
loads i.e. forces and toques which are mentioned in the load
cases. The material used was mild steel. After the material
had applied we have to apply the boundary conditions
according the actual working conditions i.e. where it fixed
and where it is free. After that problem have to be solved by
using ANSYS software. In the next step we have to solve
the model in the analysis phase. The results are compared if
the results are satisfied then problem is solved and if not
then editing of model is done and again the steps should be
followed.
Fig-4.1: Solid Model
In following table particular conditions are shown in Table 4
for the typical component.
Table4: Vehicle Specification
Wheel Base 2365mm
Overall Length 4095mm
Overall Width 1575mm
Overall Height 1395mm
Ground Clearance 170mm
Turning Radius 4.8mm
Unladed Weight 870Kg
Laden Weight 1315Kg
Table4: Assumptions made for calculations
Force 2520 N
Material Mild Steel
Density 7870kg/m3
Young’s modulus 2*1011
Pa
Tensile strength 245 MPa
Poisson’s ratio 0.29
5. STATIC ANALYSIS
5.1. Introduction
The control arm bushing consist of two types of bushings, a
durable rubber bushing and inner metal sleeve. The bushing
acts as hinged Damper to support the suspension and
provide a more controllable and comfortable ride.
Fig-5.1.1 General Suspension System
The bushings are attached to the chassis or the frame of the
vehicle and the ball joint is attached to the wheel of the
vehicle.
Fig 5.1.2 MacPherson Suspension System
5.2 3D Model of Control Arm
Control arm is first modeled in CATIA software which is
outstanding CAD software. CATIA is very user friendly
software which makes modeling so easy.

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Fig 5.2.1 Drawing Reference Points
Fig 5.2.2 Sketching the Front Bushing
5.3. Mesh Generation
In this analysis mesh generation is auto generation by the
ANSYS software, after that sizing of 5mm was given to the
suspension arm. Tetrahedral 10-noded elements were used
to mesh the lower suspension arm.
Fig 5.3 Mesh Model
 No of Nodes – 9634
 No of Elements- 34175
 Element Type – Tetrahedral (10 node)
5.4. Loading and Boundary Conditions
5.4.1 Static Loads on the Vehicle
Weight of vehicle acting at its center of gravity
G= m.g
As we know approximately 0.39% of weight of the whole
body or car is carried by front wheels and 0.61% weight
carried by rear wheels.
So reaction equations are-
Reaction on front wheels (R1) = 0.39 * G
Reaction on rear wheels (R2) = 0.61 * G
So equation becomes-
R1 S1 = R2 S2
As we know
S = S1 + S2
Loads on front axle and rear axle are found by using the
equilibrium equation-
GFA = G* S2/S
GRA = G* S1/S
Static load on one wheel of the front wheel-
GFAW = GFA/2
Table 5.4
Parameters Description
G Weight of vehicle acting at CG
m Mass
G Acceleration due to gravity
R1 Reaction on front wheels
R2 Reaction on rear wheels
S1 Distance between CG and front axel
S2 Distance between CG and rear axel
S Wheel base
GFA Loads on front axel
GRA Loads on rear axel
GFAW Loads on one wheel of front axel
Loads are in form of force values and moments. The
boundary conditions applied on the component.

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Fig 5.4.1 Loading Condition
5.4.2. Boundary Conditions
Fig 5.4.2 Loading Condition
6. RESULTS
Many features were analyzed like stress and displacement
from FEM analysis and results that were found are given
below,
6.1. Stress Analysis
In stress analysis of lower suspension arm subjected to high
stress shown in figure 10. According to the methodology to
safer the design stress induced in arm should be less than the
yield strength of the material. The stress found from the
analysis is 211.06MPa.
Fig 6.1 Equivalent Stress
6.2. Total Deformation
Total deformation shows that at what stage the component
will deflect from its original position. Total deformation
should be within the limits and Total deformation found in
the analysis was 0.65515mm.
Fig 6.2 Total Deformation
Table 6
Parameter Results
Equivalent stress 211 MPa
Deformation 0.65515 mm
Safety Factor 1.1845
7. CONCLUSION
1. In stress analysis, the stresses of material for the given
loading condition fall well in within the yield stress i.e.
211.06 MPa as shown in figure 6.1.
2. The total deformation due to the force applied on the
suspension arm was 0.65515 mm which is maximum
was at the ball bearing of the suspension arm shown in
figure 6.2
3. The minimum safety factor was 1.1845 which shows
the component is safe.

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REFERENCES
[1]. M.M Rahman, K. Kadirgama, M.M. Noor, M.R.M.
Rejab, S.A. Kesulai, “Fatigue Life Prediction of Lower
Suspension Arm Using Strain-Life Approach” European
Journal of Scientific Research 2009
[2]. Dattatray Kothawale, Dr. Y.R. Kharde, “Analysis of
Lower Control Arm in Front Suspension System Using FEA
Approach” Internationals Journals of Engineering Research
and Development 2013
[3]. Pratik S. Awati, Prof. L.M. Judulkar, “Modal and
Stress Analysis of Lower Wishbone Arm Along With
Topology” International Journal of Applications or
Innovation in Engineering & Management 2014
[4]. Vijaykumar V Solanki, Prof. N.S. Patel, “Static
Analysis Geometric Optimization of Independent
Suspension Link” International Journals of Thesis Projects
and Dissertations 2014
[5]. Sagar Kailas Darge, Prof. S.C. Shilwant Swapnil, S
Kulkarni, “Review on Design and Evaluation of
Suspension Arm for an Automobile Using Fem”
International Journals Of Advance Engineering Research
And Studies 2014
[6]. Prof. A.M. Patil, Prof. A.S. Todkar, Prof. R.S.
Mithari, Prof. V.V. Patil,” Experimental and Finite
Element Analysis of Left Side Lower Wishbone Arm of
Independent Suspension System” Journal of Mechanical and
Civil Engineering 2013.

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