Based on physical and thermal properties graphite cast iron has got more strength than sand cast Mg alloy and it is clear from the results that the load carrying capacity of former is larger than the later. Hence Graphite cast iron is preferred for the manufacture of rack and pinion. In static structural analysis the total deformation and von - mises stresses are more in sand cast Mg alloy than graphite cast iron. Hence graphite cast iron has better strength than Sand cast Mg alloy. In modal analysis the number mode shapes are higher for graphite cast iron than sand cast Mg alloy. Under transient conditions the total deformation of Graphite CI is less than that of Sand cast mg alloy. Hence former is preferred under Transient conditions. Under fatigue loads the damage is more in sand cast Mg alloy. Hence graphite CI is preferred for manufacturing of Rack and pinion. Hence Keeping all the analysis in view the graphite cast iron is preferred over sand cast Mg alloy.

1. Analysis of Gear and Rack Transmission System
A PROJECT REPORT
Submitted
In the partial fulfillment of the Requirements for the Award of the Degree of
BACHELOR OF TECHNOLOGY (B.Tech)
In
MECHANICAL ENGINEERING
By
SAHIL SHARIFF [15311A03I9]
K. NAGARAJU [15311A03J2]
PRAVEEN [15311A03J9]
UNDER THE GUIDANCE OF
DR. A. PURUSHOTHAM
PROFESSOR
DEPARTMENT OF MECHANICAL ENGINEERING
SREENIDHI INSTITUTE OF SCIENCE & TECHNOLOGY
(Approved by AICTE, New Delhi and Affiliated JNTUH: Hyderabad)
Yamnampet, Ghatkesar, Hyderabad – 501 301
November, 2018.

2. SREENIDHI INSTITUTE OF SCIENCE AND TECHNOLOGY
Yamnampet, Ghatkesar, Hyderabad – 501 301
Date: 1-11-2018
CERTIFICATE
This is to certify that the project report entitled “Analysis of Gear and Rack
Transmission System” being submitted by SAHIL SHARIFF bearing the Roll
No.15311A03I9, K.NAGARAJU bearing the Roll No. 15311A03J2, PRAVEEN bearing the
Roll No. 15311A03J9 in partial fulfillment for the award of Bachelor of Technology degree in
MECHANICAL ENGINEERING, Sreenidhi Institute of Science & Technology affiliated to
Jawaharlal Nehru Technological University, Hyderabad (Telangana), is a record of bonafide work
carried out by them under our guidance and supervision.
The results embodied in the report have not been submitted to any other University or
Institution for the award of any degree or diploma.
(Dr.A. Purushotham) Dr.T.Ch. Shiva Reddy
Project Guide HOD, MECH

3. DECLARATION
We hereby declare that the work described in this thesis “Analysis of Gear
and Rack Transmission System” which is being submitted by us in partial
fulfillment for the award of Bachelor of Technology in the Department of Mechanical
Engineering, Sreenidhi Institute Of Science & Technology affiliated to Jawaharlal
Nehru Technological University Hyderabad, Kukatpally, Hyderabad (Telangana) is the
result of investigations carried out by us under the Guidance of Dr.A.Purushotham,
Professor, Department of Mechancial Engineering, Sreenidhi Institute Of Science &
Technology , Hyderabad.
The work is original and has not been submitted for any Degree/Diploma of this or
any other university.
Place: Hyderabad
Date: 1-11-2018
Signature:
SAHIL SHARIFF [15311A03I9]
K. NAGARAJU [15311A03J2]
PRAVEEN [15311A03J9]

4. ACKNOWLEDGEMENTS
We thank Dr.A. Purushotham, Professor, Dept of MECH, Sreenidhi Institute of
Science & Technology, Hyderabad for his valuable comments and suggestions that greatly
helped in improving quality of thesis.
We would like to express our sincere gratitude to Dr. T. Ch. Shiva Reddy, Professor,
Head of the department, Mechanical Engineering, Sreenidhi Institute of Science &
Technology, Hyderabad for his continued support and valuable guidance and
encouragement extended to us during our research work. We thank him for his
painstaking efforts to guide us throughout our research work.
We thank Mr. SRINIVASULU, Associate Professor of MECH, Sreenidhi Institute
of Science & Technology, Hyderabad for her valuable advice, support and help during our
research work.
We thank all our teachers and professors for their valuable comments after
reviewing our research papers.
We wish to extend our special thanks to all our colleagues and friends who helped
directly or indirectly to complete our research work.
We extend my thanks to our parents and all our family members for their unceasing
encouragement and support who wished us a lot to complete this work.
SAHIL SHARIFF
K. NAGARAJU
PRAVEEN

5. ABSTRACT
Gear design is considered to be one of the most important and complicated
fields of mechanical engineering design, because of its wide usage and applications,
in mechanical and electrical systems. Due to the high working speed requirements
in industry of rotating components, gear design development becomes quite
noticeable and rapid in the vicinity of parameters, and effects of dynamic load and
dynamic stresses on its performance.
This project Rack and pinion gears are used to convert rotation into linear
motion. The flat, toothed part is the rack and the gear is the pinion. A piston coaxial
to the rack provides hydraulic assistance force, and an open centered rotary valve
controls the assist level. A rack and pinion gears system is composed of two gears.
The normal round gear is the pinion gear and the straight or flat gear is the rack.
The rack has teeth cut into it and they mesh with the teeth of the pinion gear. A ring
and pinion gear is the differential's critical point of power transfer. A ring and
pinion gear set is one of the simplest performance modifications that can be
performed on a vehicle.
In this project I have analysed the Rack and pinion system by doing Static
structural analysis, modal analysis, Transient static structural analysis and fatigue
analysis. In all these analyses I have used the same mesh size ( same number of
nodes and same number of elements) for the purpose of comparison of the results.
Method of mesh element : Hex Dominant
Order: Linear order elements
Mesh type: All quad
Mesh size : 3mm, 12mm at contact zones and other zones respectively.
Inflation: 10 layers at the meshed zone
No.ofNodes:15107
No. of Elements: 18826

6. 1. Static structural analysis:
In this analysis the rack and pinion system is subjected to static loads and various
results are drawn from it such as
1. Von- Misses stress
2. Deformation
3. Pressure generated at the contact region.
2. Modal analysis:
In modal analysis the Rack and pinion system is subjected to various frequencies
ranging 0 to 1000 HZ and the modal behavior of the system is studied. In modal
analysis the number mode shapes are higher for which material is being studied and
the material with lest modal shapes is selected.
3. Transient static structural analysis:
In Transient static structural analysis the model is subject to varying and time
dependant loads and the behavior of the system under transient load ( varied with
time) conditions is studied. Under transient conditions the total deformation of
which material is smaller is observed and is preferred under Transient conditions.
4. Fatigue analysis using Transient Condition :
Under fatigue analysis the fatigue strength of the system is studied by subjecting it
to fatigue loads. The model is subjected to fatigue loads under transient conditions.
The following results are drawn from the analysis:
1. Fatigue Life
2. Damage
3. Safety Factor
Finally considering all the analysis and results the best material for the Rack
and Pinion system is chosen from the given set of materials.

7. CONTENTS:
1. Introduction
2. Problem Statement
3. Literature Survey
4. Static structural analysis
5. Modal analysis
6. Transient static structural analysis
7. Fatigue analysis
8. Conclusion
9. Remarks
10. References

8. 1. INTRODUCTION
The advantages of high transmission efficiency, strong carrying capacity and the
stability of the transmission ratio, the gear and rack transmission system is commonly
used in force and motion transmission in the mechanical system. The reliability and
stability of the gear and rack directly influences the regular operation of the
mechanical equipment.
The traditional measures are usually used to calculate the contact stress and bending
stress which can only help obtain the value of a single point of time on one contact
surface. Moreover, it has the following problems: complicated calculation process,
time-consuming, inexactitude of the calculated result. The structure static analysis is
a systematic verification process in steady load.
However, when the load changes with time, the dynamics and statics characteristics
which the system represented are different. The three-dimensional model of the gear
and rack transmission system was built by the 3D design software UG, and the model
analysis was conducted on the gear and rack transmission system by the software of
ANSYS Workbench in order to identify the natural frequencies of the gear and rack
transmission system. On this basis, transient dynamic analysis of the gear and rack
system is carried out to get equivalent stress distribution at different times in the gear
and rack meshing contact process and the strength of contact and bending strength of
the gear and rack is examined.
RACK AND PINION PROBLEM STATEMENT :
Rack and pinion is an assemblywhich converts the rotational motion of steering
in Linear motion of the wheels. Therefore in order to simulate it, Static analysis of
the gears and Transient analysis should be performed.
ANALYSIS OF RACK AND PINION using ANSYS:
1. Perform Static Structural and Transient Structural Analysis on Rack and Pinion
• Input : Mesh the Geometry using HEX elements.
• (Note : This can be achieved by using different options under Mesh and
the Element size can be selectedas per the requirement in order to achieve
HEX elements)
The analysis is performed using different materials to find out the strength of
the materials under working conditions and to specify the best material for the
manufacturing of gears.

9. The different materials used are:
Material Properties :
1. Graphite Cast Iron
 Density: 7.91g/cc
 Young’s Modulus: 99GPa
 Poisson’s Ratio: 0.21
 Thermal Conductivity: 46 W/mK
 Specific Heat: 490 J/kg
2. Sand Cast Magnesium Alloy
 Density: 1.81g/cc
 Young’s Modulus: 45GPa
 Poisson’s Ratio: 0.35
 Thermal Conductivity: 62 W/m.K
Composition:
 Aluminium 10.7%
 Magnesium 90%
 Zinc 0.3%
ANALYSIS :
(Note:All the analysis are to be performed for all the materials specifiedabove)
Case 1: Static Analysis (for all the types of materials):
1. Apply Force of 1000N on one teeth.
Output :
1. Von- Misses stress
2. Deformation
3. Pressure generated at the contact region.
Case 2: Perform modal analysis to find the mode shapes under 1000Hz.
Output :
1. Deformation of all Mode shapes under 1000Hz.

10. Case 3:
1. Apply transient load when vehicle is steering on zig-zag road i.e Left - Right
- Left.
2. The pressure acting on single teeth during mesh is 1000N when steering
towards Left from 0 - 0.5 seconds i.e on 5 teeths.
3. One teeth will be in contact with the other at a time for 0.1 seconds.
4. Step 3 and 4 will be repeated when the vehicle steers towards right side from
0.6 – 1 Second
Output :
1. Von- Misses stress
2. Deformation
3. Pressure generated at the contact region.
Case 4: Fatigue analysis using Transient Condition.
Output :
1. Fatigue Life
2. Damage
3. Safety Factor

11. Literature Review
General steering system in modern vehicle either commercial or owned of
a Gear combination. Where the pinion is connected to the steering wheel
through steering column and while rotation the steering the pinion is rotated
which is in mesh with the rack which converts the rotational motion into linear
motions which moves the wheels with various geometry and positioning of the
steering unit. In India the cars are mostly found to be front wheel drive and
with the arrangement with drive shafts it made the turning of the wheels
limited.
A rod, called a tie rod, connects to each end of the rack. A complete survey of
the existing steering system of a four-wheeler was made. Currently there is no
steering which has incorporated planetary gear sets. However planetary gear
sets are used in ship steering mechanisms and vehicles automatic transmission
gear boxes. Research papers related to the design of different types of
planetary gear set (circular, noncircular), analytical expression for power
transmission, ship steering system, were studied. Dr.S.R. Shankapal (2013)
developed a four wheel steering system for a car. Production cars are designed
to understand and rarely do they over steer. If a car could automatically
compensate for a over steer problem the driver would enjoy nearly neutral
steering under varying operations conditions. In situation like low speed
cornering, vehicle parking and driving in city conditions with heavy traffic
tight spaces. Driving would be very difficult due to vehicles larger wheel base
and track width. Hence there is a requirement of a mechanism which results in
less turning radius and it can be achieved by implementing four wheel steering
mechanism instead of regular two wheel base.
S.H.Yadav (2013) made an investigation of failure of planetary gear train
due to pitting, planetary gear train is a gear system consisting of one or more
planet gears, revolving about a sun gear. And it is widely used in industries.
An epicyclical gearing system is particularly well suited for achieving a high
reduction ratio in a relative small, power dense package. It is widely
recognized that the load sharing is not equal among the planetary gear meshes.
Similarly the stress distribution at each mesh point contains variability. Pitting
is a surface fatigue failure of the gear tooth. It occurs due to misalignment;
wrong viscosity selection of lubricant used, and contact stress exceeding the
surface fatigue strength of the material. R.Masilamani (2015) made an
experimental analysis of reducing steering ratio to reduce turning ratio, the
concept has been developed to reduce the driver’s effort during parking or
maneuvering sharp curves. Using the additional planetary gear set with the
existing steering gear box, steering ratio can be changed and hence the input

12. speed to the steering wheel can be altered when to the steering gear box. On
installing the planetary gear set and the modified rack and pinion steering gear
box, the number of rotations made by the steering wheel for the given angle of
road wheel rotation is altered. Dr.Dinesh.N.Kamble has developed a concept
based on the analysis of the transmission mechanism of angle superposition
with active front steering system. A controller of variable steering ratio for
AFS system is designed and virtual road tests are made in car. The results of
simulation tests validate the controller performance and the advantage of the
variable steering ratio function, also show that the driving comfort is

13. STATIC STRUCTARAL ANALYSIS:
A static structural analysis determines the displacements, stresses, strains, and forces in
structures or components caused by loads that do not induce significant inertia and
damping effects. Steady loading and response conditions are assumed; that is, the loads
and the structure's response are assumed to vary slowly with respect to time. A static
structural load can be performed using the ANSYS, Samcef, or ABAQUS solver.
The types of loading that can be applied in a static analysis include:
 Externally applied forces and pressures
 Steady-state inertial forces (such as gravity or rotational velocity)
 Imposed (nonzero) displacements
 Temperatures (for thermal strain)
 Preparing the Analysis
 Create Analysis System
 From the Toolbox, drag a Static Structural, Static Structural (Samcef),
or Static Structural (ABAQUS) template to the Project Schematic.
 Define Engineering Data
Material properties can be linear or nonlinear, isotropic or orthotropic, and constant or
temperature-dependent. You must define stiffness in some form (for example, Young's
modulus, hyperelastic coefficients, and so on). For inertial loads (such as Standard Earth
Gravity), you must define the data required for mass calculations, such as density.
Attach Geometry
A “rigid” part is essentially a point mass connected to the rest of the structure via joints.
Hence in a static structural analysis the only applicable loads on a rigid part are
acceleration and rotational velocity loads. You can also apply loads to a rigid part via
joint loads. The output from a rigid part is the overall motion of the part plus any force
transferred via that part to the rest of the structure. Rigid behavior cannot be used with
the Samcef or ABAQUS solver.
If your model includes nonlinearities such as large deflection or hyperelasticity, the
solution time can be significant due to the iterative solution procedure. Hence you may
want to simplify your model if possible. For example you may be able to represent your
3D structure as a 2-D plane stress, plane strain, or axisymmetric model or you may be
able to reduce your model size through the use of symmetry or antisymmetry surfaces.
Similarly if you can omit nonlinear behavior in one or more parts of your assembly
without affecting results in critical regions it will be advantageous to do so You can
define a Point Mass for this analysis type.

14. A “rigid” part is essentially a point mass connected to the rest of the structure via joints.
Hence in a static structural analysis the only applicable loads on a rigid part are
acceleration and rotational velocity loads. You can also apply loads to a rigid part via
joint loads. The output from a rigid part is the overall motion of the part plus any force
transferred via that part to the rest of the structure. Rigid behavior cannot be used with
the Samcef or ABAQUS solver.
If your model includes nonlinearities such as large deflection or hyperelasticity, the
solution time can be significant due to the iterative solution procedure. Hence you may
want to simplify your model if possible. For example you may be able to represent your
3D structure as a 2-D plane stress, plane strain, or axisymmetric model or you may be
able to reduce your model size through the use of symmetry or antisymmetry surfaces.
Similarly if you can omit nonlinear behavior in one or more parts of your assembly
without affecting results in critical regions it will be advantageous to do so
Large Deflection is typically needed for slender structures. A rule of thumb is that you
can use large deflection if the transverse displacements in a slender structure are more
than 10% of the thickness.
Small deflection and small strain analyses assume that displacements are small enough
that the resulting stiffness changes are insignificant. Setting Large Deflection to On will
take into account stiffness changes resulting from changes in element shape and
orientation due to large deflection, large rotation, and large strain. Therefore the results
will be more accurate. However this effect requires an iterative solution. In addition it
may also need the load to be applied in small increments. Therefore, the solution may
take longer to solve.

15. Input:
Output:
Graphite cast iron:
Total deformation Vonmises stress
Sand cast Mg Alloy
Total deformation Vonmises stress

16. 2. MODAL ANALYSIS
Using ANSYS workbench for the dynamic analysis of the gear and rack system,
modal analysis of the gear and rack system must be done in the first place. The modal
analysis belongs to the dynamic analysis and its main purpose is to find out the
natural frequency of the gear and rack system and to provide the data for the transient
dynamics analysis of gear and rack system. By comparing the natural frequency and
meshing frequency of the gear and rack system, the speed of the gear is, whether it’s
reasonable, can be determined. Regulating the gear speed can prevent its natural
frequency.
Finite Element Modeling.
In order to adequately reflect the variation of gear and rack contact result, the gear and rack
system requires intensive meshing. The gear and rack are sliced in this paper. Dense
meshing is done only on the gear contact area. The local mesh refinement can reduce the
number of skewed mesh. Better mesh can make the results more accurate. In the gear and
rack meshing region, the element size is set 3 mm, and the unimportant regional element
size is set 10mm. There are
Fig. (2). The finite element model of the gear and rack system.
Imposing Constraints.
The main purpose of the modal analysis is to find out the natural frequency of the gear and
rack system. So there is no need to apply load to the model. Only a degree of freedom
constraint is needed. In order to match the actual working conditions, it must be ensured that
the gear only rotates around the Z axis and the rack only translates along the X direction. A
revolute-ground constraint on the gear and a translational-ground constraint on the front

17. surface of the rack, need to be added in Connections. Then, a cylindrical support on the gear
and a displacement on the bottom surface of the rack in modal are added. According to the
actual condition of the rack, add forced displacement to the rack in the X, Y, Z directions.
Constraint conditions is shown in Fig. 3
Fig. (3). Schematic diagram of constraint.
Modal Analysis Results and Discussion.
Modal analysis of the system, generally, needs to compute a few lower-order
frequencies. Because higher modes have little effect on the dynamic characteristics of
the structure and usually only the low order natural frequency may cause the system
resonance. The first six order natural frequency is obtained by the post-processor.
According to the definition of the gear meshing frequency, gear meshing frequency
equals to the rotational frequency multiplied by the number of teeth. When the
number of gear teeth is 25, the gear meshing frequency is 16Hz at the speed of
0.65r/s by calculation, which is far less than the lowest natural frequency. Therefore,
it is likely to avoid the resonance frequency. In order to improve production
efficiency, the speed of gear can be improved, which can have different external
excitation conditions in different production efficiency.

18. CASE 2: Modal Analysis
Sand cast Mg alloy:
No.of mode shapes: 5
Frequency: 0 to 1000Hz
Graphite cast iron:
No. ofmode shapes : 7
Frequency :0 to 1000HZ

19. 3. TRANSIENT STATIC STRUCTURAL ANALYSIS
Gear and rack system is commonly used as a component in mechanical device, so its
strength check has practical implications. Typically the contact stress, bending stress of gear
and rack are computed by traditional methods. However, the conventional formula to
calculate the contact stress in the gear is only on one certain point of time and on one
contact surface. The pitch circle circumferential force acting on the top gear can be used to
calculate the bending stress. The contact stress calculated by transient dynamics analysis in
this paper is a range of values which describes the contact stress values at different times
and in different contact position of the gear and rack. At different point of time, the
influence of the bending of gear and rack is different due to the size of the meshing force
and the acting position. This transient dynamics description method can describe the gear
and rack meshing process more realistically .
Transient Dynamic Finite Element Model.
As discussed above, through modal analysis of gear and rack intrinsic characteristics of the
system are obtained. On the basis of the above, the transient response analysis is performed
in this part by adding the transient dynamic module (Transient Structural).
Load Settings.
First, set the gear speed. Here the steady speed of gear is set to 0.65r/s. The default units in
ANSYS workbench is rad/s and the speed of gear can be transformed into 4.08rad/s, as
shown in Fig. (4). Second set the rack load. In this paper the gear drives the rack to transmit
power, so it needs to apply horizontal load along the moving direction of the rack. Set the
load to 400N. A cylindrical support needs to be added to the gear and displacement on the
bottom surface of the rack is added in Transient. According to the actual condition of the
rack, add forced displacement to the rack in the X, Y, Z directions. Finally add the options
of the results in Solution and the transient analysis setting is completed
Fig. (4). Gear load settings.
Transient Dynamic Analysis Results and Discussion.
The transient dynamics analysis is done on the gear and rack meshing process. The
equivalent stress contour of the gear and rack in the meshing process is shown in Fig.
The behavior of the Rack and pinion system which when subjected to transient loads is
sown in the figure below.

20. CASE3:TRANSIENT STRUCTURAL
Timestep min.stress Max.Stress
0.1 1.9971e-003 153.08
0.2 2.009e-003 153.64
0.3 2.006e-003 153.55
0.4 2.0231e-003 154.1
0.5 2.0064e-003 153.71
0.6 2.0067e-003 153.76
0.7 2.0015e-003 153.14
0.8 2.001e-003 153.15
0.9 2.033e-003 154.58
1. 1.9949e-003 153.07
Timestep min.stress Max.Stress
0.1 4.4492e-002 0.33471
0.2 4.4638e-002 0.33584
0.3 4.4649e-002 0.3359
0.4 4.4752e-002 0.33671
0.5 4.4809e-002 0.33708
0.6 4.4728e-002 0.33649
0.7 4.4719e-002 0.33635
0.8 4.4659e-002 0.33599
0.9 4.462e-002 0.33575
1. 4.4557e-002 0.33514
Timestep min.stress Max.Stress
0.1 3.0264e-003 152.26
0.2 3.0227e-003 152.74
0.3 3.0324e-003 152.78
0.4 3.0427e-003 153.13
0.5 3.042e-003 153.33
0.6 3.0398e-003 153.04
0.7 3.0382e-003 153.03
0.8 3.0301e-003 152.8
0.9 3.0238e-003 152.68
1. 3.0287e-003 152.48
Sandcast Mgalloy
Graphitecast iron
Timestep min.stress Max. Stress
0.1 2.0691e-002 0.15593
0.2 2.0767e-002 0.15652
0.3 2.0769e-002 0.15637
0.4 2.0833e-002 0.15697
0.5 2.0784e-002 0.15656
0.6 2.0793e-002 0.1566
0.7 2.0703e-002 0.15599
0.8 2.0701e-002 0.156
0.9 2.088e-002 0.1575
1. 2.0704e-002 0.15588
Totaldeformation
Vonmisesstress
Input

21. case4: Fatigue analysis:
There are two general categories of fatigue analysis: — Fatigue based on crack
formation. — Fatigue based on crack growth. The choice of analysis type is based on
the given application. — When in the design phase, or for components requiring
only a few cycles of life, crack formation may be sufficient. — For highly engineered
parts, for components that are manufactured in bulk such as automotive parts, or for
in-service life prediction, crack growth may be required.
Why Fatigue Analysis? :
While many parts may work well initially, they often fail in service due to fatigue
failure caused by repeated cyclic loading – In practice, loads significantly below
static limits can cause failure if the load is repeated sufficient times – Characterizing
the capability of a material to survive the many cycles a component may experience
during its lifetime is the aim of fatigue analysis
Common Decisions for Fatigue Analysis:
– Fatigue Analysis Type
– Loading Type – Mean Stress Effects
– Multiaxial Stress Correction
– Fatigue Modification Factor
This fatigue analysis is performed under transient load conditions. The
various results and graphs plotted are shown in figure below.

22. CASE4:FATIGUEANALYSIS
INPUT:
Damage
Life
Safetyfactor
Life
Damage
Safetyfactor
Graphitecastiron
SandcastMgAlloy
loading
loading

23. CONCLUSION:
Type of
Analysis
Results: Graphite
cast iron
Sand
cast
Mg
Alloy
Static structural Total deformation(mm) .1572 .3381
Von-mises stress ( Mpa) 150.25 152.32
Modal Analysis
Frequency
range:0 to 1000
Hz
No. of mode shapes 7 5
Last mode frequency (Hz) 895.97 717.43
Transient
structural
Total deformation(mm) .155 .3351
Von-mises stress (Mpa) 153.07 152.48
Fatigue Analysis Life 1e6 1e6
No. of cycles 70933 70255
Damage 14098 14234
Safety factor 15 15

24. Remarks:
1. Based on physical and thermal properties graphite cast iron has got more
strength than sand cast Mg alloy and it is clear from the results that the load
carrying capacity of former is larger than the later. Hence Graphite cast iron is
preferred for the manufacture of rack and pinion.
2. In static structural analysis the total deformation and von - mises stresses are
more in sand cast Mg alloy than graphite cast iron. Hence graphite cast iron
has better strength than Sand cast Mg alloy.
3. In modal analysis the number mode shapes are higher for graphite cast iron
than sand cast Mg alloy.
4. Under transient conditions the total deformation of Graphite CI is less than that
of Sand cast mg alloy. Hence former is preferred under Transient conditions.
5. Under fatigue loads the damage is more in sand cast Mg alloy. Hence graphite
CI is preferred for manufacturing of Rack and pinion.
6. Hence Keeping all the analysis in view the graphite cast iron is preferred over
sand cast Mg alloy.
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