Design evaluation and optimization of steering yoke of an automobile

IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 11 | Nov-2014, Available @ http://www.ijret.org 80`
DESIGN EVALUATION AND OPTIMIZATION OF STEERING YOKE
OF AN AUTOMOBILE
S.K. Chandole1
, M.K. Bhavsar2
, S.S. Sarode3
, G.R. Jadhav4
1
Assistant Professor, Mechanical Engineering, Late G.N.S COE Anjneri, Nasik, Maharashtra, India
2
PG Scholar, Mechanical Engineering, Amrutvahini COE Sangamner, Ahmednagar, Maharashtra, India
3
Assistant Professor, Mechanical Engineering, Late G.N.S COE Anjneri, Nasik, Maharashtra, India
4
PG Scholar, Mechanical Engineering, Late G.N.S COE Anjneri, Nasik, Maharashtra, India
Abstract
The purpose of a steering system is to control the direction of the vehicle by operating the steering wheel of the steering system.
The steering columns in a steering system are one of the main devices of an automobile. It is a very important part to attain stability
and steady movement of the vehicle. The steering yoke consists of two forged-steel yokes or forks joined to the two shafts being
coupled and situated at right angles to each other. A spider hinges these two yokes together. Since the arms of the spider are at
right angles the spider arm rocks backwards and forward between four extreme positions. Motion transmission system of vehicles
consist several components which sometimes encounter unfortunate failures. Some common reasons for the failures may be
manufacturing, design faults, maintenance faults, raw material faults, material processing faults as well as the user originated
faults.
In this paper structural optimization of the steering yoke is carried out. For modeling of the component, CATIA V5 R17 software
is used. It has been found that there are essentially in two stages of the design process that structural optimization can be applied.
In the early stage of concept generation, topology optimization should be used to develop an efficient structure from the
beginning. At this level an automatized variation of optimization parameters was proven useful to and the best feasible design
possible. In the later stage, shape and size optimization should be used to fine-tune the structure realized from the topology
optimization and carried out physical experimentation to validate the model.
Keywords: Steering Yoke, Structural optimization, CATIA V5, Hyperworks
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1. INTRODUCTION
The purpose of a steering system is to control the direction of
the vehicle by operating the steering wheel of the steering
system. Movement of steering wheel by the driver should
cause an accurate response of the road wheels. The
intermediate shaft connects the steering shaft to the steering
pinion. These components cannot be arranged on the same
axis due to the vehicle design limitations. They are arranged
with the universal joints [1]. Control of vehicle should be
maintained with safety throughout the speed range with little
effort and over a wide range of road surfaces under all
conditions [2-3].
The subassembly of steering yoke associated with this
project work consists of two forged-steel yokes or forks
joined to the two shafts being coupled and situated at right
angles to each other. Steering Yoke would be the topic of
interest for this case-study. A spider hinges these two yokes
together. Since the arms of the spider are at right angles [4].
Topology optimization is a powerful structural optimization
method that combines a numerical solution method, usually
the finite element method, with an optimization algorithm to
find the optimal material distribution inside a given domain.
The purpose of topology optimization is to get the design that
would be obtained on a uniformly fine mesh, but at a much
lower computational cost by reducing the total number of
elements and having fine elements only where and when
necessary [5-6].
Fig 1: Cross Type Universal Joint
For modeling of the steering yoke, CATIA V5 R17 software
is used. In the last decade the use of commercial optimization
software for topology and shape optimization in the industry
has increased rapidly and has shown to be applicable to many
different types of problems. The idea is that the designer and
the structural engineer both are involved in the initial stage

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Volume: 03 Issue: 11 | Nov-2014, Available @ http://www.ijret.org 81
when the first design proposal is conceived. Topology
optimization is used to generate a good design concept [5].
Using this software, we can identify the nature and
characteristics of stresses acting on the steering yoke.
Figure shows the 3D model geometry of steering yoke
assembly
The software that will be used are the preprocessor Hyper
Mesh, the optimization tool Optistruct and the postprocessor
Hyper View, all of them products of Altair Engineering.
Fig 2: 3D Geometry Steering Yoke assembly
2. OBJECTIVE
The main aim of the project is to determine the Von Misses
stresses, Element density distribution and Optimization in
the existing Steering yoke.
Structural optimization is one application of optimization.
Here the purpose is to find the optimal material distribution
according to some given demands of a structure. Some
common functions to minimize are the mass, displacement
or the compliance (strain energy).
This problem is most often subject to some constraints, for
example constraints on the mass or on the size of the
component. This optimization is traditionally done manually
using an iterative intuitive process that roughly consists of
the following 3 steps:
1. A design is suggested
2. The requirements of the design is evaluated, for example
by a finite element analysis (FEA)
3. If the requirements are fulfilled, the optimization process
is finished. Else, modifications are made, a new improved
design is proposed and step 2-3 are repeated.
3. GENERIC SPECIFICATIONS FOR A
STEERING YOKE
 Material used: - Rolled/ Forged Steel - Carbon Steel
 C1021 or suitable
 Heat Treatment - Annealed.
 Typical hardness of the material – HRC 35-48
 Application for case study –Automobile (Steering yoke)
Table 1: Mechanical properties of C-1021 Steel
Properties Value
Tensile strength, (MPa) 420
Yield strength (MPa) 230
Youngs modulus, E (GPa) 205
Elongation (%) 24%
Reduction in area (%) 48%
4. RESULT OF FINITE ELEMENT ANALYSIS
AND COMPARISION WITH EXISTING
RESULTS
By using hyper works software there are three steps. 1. Pre-
processing, 2.processing (or) solution, 3.Post- processing.
4.1 Pre-processing
After modeling the component and importing to hypermesh
window meshing is carried out.
Meshing details-
Number of elements = 27997
Number of nodes = 28647 Element size = 2.5
Mesh type = Second order Tetrahedral meshing
4.2 Processing
Boundary conditions - 350 Nm torque applied at top of
steering yoke.
Constraint given: - translation and rotational (1-6) at lower
side.
4.3 Post-Processing
After successfully completed the process, the results can be
viewed in hyper view. The three important results are
noted and they are:
1. Vonmises elemental stress counter
2. Displacement counter
3. Mass counter
Firstly the component was designed for that vonmises
elemental stress and displacement results are obtained from
hyper works.

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4.3.1 Vonmises Element Stress for Existing and
Modified Yoke
Following are Figures shows the optimized results along
with the results of figures in reference paper and
comparison for static analysis of steering yoke at torque
350 N-m.
Fig 3: Von-Mises stresses contour for existing and modified
steering yoke
4.3.2 Displacement Counter for Existing and
Modified Steering Yoke
with the results of figures in reference paper.
Fig 4: Displacement contour for existing and modified
steering yoke
4.3.3 Mass Counter for Existing and Modified
Steering Yoke
with the results of figures in reference paper.
Fig 5: Mass contour for existing and modified steering yoke
5. EXPERIMENTAL SETUP
The objective of current work is to determine the stresses
and displacement acting on the steering yoke by using
Universal Testing Machine (UTM). After calculating the
maximum stress value this value is compared with software
values calculated by using Von-misses theory. Design of
steering yoke by theoretical approach is very tough job
because of its complicated structure and subjected to
combined loads. Stresses which produced in Steering yoke
assembly find out by experimentally using strain gauge
technique which carried out.

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Fig 6: Universal Testing Machine (UTM)
Table 2: Readings and calculations
Load
(F)
(N)
Torque
(T)
(N-m)
Strain gauge
reading
(ε)
(microns)
Strain
(ε)
(mm)
Stress
(σ)
(N/mm2
)
66.67 10 32.6 0.3260 x 10-4
6.68
133.33 20 65.19 0.6519 x 10-4
13.36
200 30 97.79 0.9779 x 10-4
20.04
266.67 40 130.4 1.3040 x 10-4
26.73
2266.7 340 1109 1.1093 x 10-3
230.5
2333.4 350 1141 1.1414 x 10-3
233.9
5.1 SAMPLE CALCULATIONS
Calculation is done only last reading; the output voltage of
Wheatstone bridge circuit (Vo) will be equal to:
Where,
Vo = Output voltage of bridge
Vex = Input voltage of bridge
∆L/L = ε = strain
Gauge factor for strain gauge = 2
Using the above equation strain gauge reading,
Strain = ε = 1141 microns = 1.1414 x 10-3
mm.
Now by using Hooke’s law,
Stress = Young’s modulus of elasticity x strain
σ = E x ε
= 2.05 x 10 05
x 1.1414 x 10-3
= 233.98 N/mm2
= 234 N/mm2
………………Experimental value
σ = 217 N/mm2
………………Software value
6. RESULTS
Thus the steering yoke is analyzed by using hyper works
software and the obtained results are compared with
experimental results. Here the results obtained i.e. Stresses
observed in modified yoke are greater than yield limit.
There is no plastic straining and permanent set. Therefore the
steering yoke is safe.
There is a fairly good agreement between the
Experimental result and FEA/software result at stressed
location of steering yoke.
Table 3: Comparison / Interpretation of the results
Parameters
Existing
yoke
Modifie
d yoke
Experim
ental
result
A
Torque (N-
m)
350 350 350
Maximum
stress
(N/mm2
)
386 217 234 7.83
Displacemen
t (mm)
9.773 ×
10-2
9.378 ×
10-2 ______
Mass (gram) 450 386 395
A = Percentage deviation of FEA/software value from
Experimental value.

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Fig 7: Comparison of Torque Vs. FEA and Experimental
Stress
7. CONCLUSION
In this paper work the design and finite element analysis of
steering yoke used in automobiles by HYPER MESH is
carried out. The steering yoke is analyzed for the stress
produced under torque load conditions. Experimental results
are compared with FEA/software result. This work involves
the comparison of existing yoke and modified yoke under
static loading conditions. The conclusions from the results
are as follows:
1. Steering yoke is analyzed under constant torque load
350 N-m from steering column.
2. From the FEA/software result, the maximum stress
observed in the modified steering yoke is 217
N/mm2 and the material Yield stress value is 230
N/mm2. Hence the design of modified steering yoke
is safe.
3. The mass of modified yoke is reduced by 16.58%
over existing/original steering yoke.
4. From the experimentation work it is observed that,
the maximum stress in the modified steering yoke is
234 N/mm2 and the material Yield stress value is
230 N/mm2. Hence the design of modified steering
yoke is safe.
5. Variation of 7.83 % is observed in maximum stress
among experimental values and FEA/software
values.
ACKNOWLEDGEMENTS
The author special thanks for valuable guidance by
Mechanical Engineering department of Late G. N. Sapkal
College of Engineering, Anjneri, (Nasik).
REFERENCES
[1] S.Kinme, T.kamikawa and A.nishino
“Development of stamped Yoke for high rigidity
intermediate shaft” Technical report, Koya
engineering journal English edition No. 165E
(2004)
[2] Dr. Kirpal Singh, “Automobile Engineering”
Volume 1, Standard publication publications, New
Delhi, 2004, Page no.10-15.
[3] R. B. gupta, “Automobile engineering” 12th
edition- 2009, Page No.538-539 & 595-606.
[4] Mr. P.G. Thate and Prof. D.S. Bajaj, “Review on
Failure Analysis of yoke assembly of a
transmission drive shaft subjected to Torsion and
Shear” IJERT, ISSN: 2278-0181 Volume-2, Issue-
10, October-2013.
[5] Mr. Anton olason and Daniel tidman, “
Methodology for Topology and Shape
Optimization in the Design Process” ISSN 1652-
8557, Department of Applied Mechanics, Chalmers
University of Technology, Sweden.
[6] Eric DE STURLER, Glaucio H. PAULINO and
Shun WANG, “Topology optimization with
adaptive mesh refinement” Proceedings of the 6th
International Conference on IASS-IACM 2008:
“Spanning Nano to Mega” 28-31 May 2008,
Cornell University, Ithaca, NY, USA.
BIOGRAPHIES
Santosh Kailas Chandole, Has
completed ME in Design Engineering &
currently working as an Assistant
Professor in Late G. N. Sapkal COE,
Anjaneri, Dist:- Nasik., Maharashtra,
India
Mikhil Kailas Bhavsar, Pursuing ME in
Design Engineering at Amrutvahini COE
Sangamner, Dist: - Ahmednagar,
Maharashtra, India
Santosh Saheberao Sarode, Has
completed ME in Design Engineering &
currently working as an Assistant
Professor in Late G. N. Sapkal COE,
Anjaneri, Dist:- Nasik, Maharashtra, India
Gokul Ramdas Jadhav, Pursuing ME in
Design Engineering at Late G. N. Sapkal
COE, Anjaneri, Dist:- Nasik.,
Maharashtra, India
0
50
100
150
200
250
300
350
400
0 50 100 150 200 250
Torque(N-m)
Stress (N/sq. mm)
Torque Vs. Stress
Experimen
tal Stress

Design evaluation and optimization of steering yoke of an automobile

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Design evaluation and optimization of steering yoke of an automobile