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ABSTRACT
The purpose of the car wheel rim provide’s a firm base on which to fit the tire. Its
dimensions, shape should be suitable to adequately accommodate the particular tire required
for the vehicle. In this study a tire of car wheel rim belonging to the disc wheel category is
considered. Design in an important industrial activity which influences the quality of the
product. The wheel rim is designed by using modelling software catiav5r18. In modelling the
time spent in producing the complex 3-D models and the risk involved in design and
manufacturing process can be easily minimised. So the modelling of the wheel rim is made
by using SOLID WORKS. Later this SOLID WORKS model is imported to ANSYS for
analysis work. ANSYS software is the latest used for simulating the different forces, pressure
acting on the component and also for calculating and viewing the results. A solver mode in
ANSYS software calculates the stresses, deflections, bending moments and their relations
without manual interventions, reduces the time compared with the method of mathematical
calculations by a human. ANSYS static analysis work is carried out by considered two
different materials namely aluminium and forged steel and their relative performances have
been observed respectively. In addition to this rim is subjected to vibration analysis (modal
analysis), a part of dynamic analysis is carried out its performance is observed. In this paper
by observing the results of both static and modal analysis obtained forged steel is suggested
as best material.
Keywords: ANSYS, SOLID WORKS, Stress Analysis, Wheel Rim.
2. INTRODUCTION
Archaeologies and historians of today see the introduction of the wheel as the real
genesis of any old civilisation. The wheel is perhaps the most significant discovery of old
times. The wheel has developed from nothing more than an oversized bearing to a fully
integral part of any modem transportation vehicle. The modern vehicle is also seen today a
fashion item to complement people’s individual requirements. Motor vehicles are produced
according to very strict rules to ensure the safety of the passengers. Every component is
therefore designed according to the criticality of the component. Wheels are classified as a
safety critical component and international cods and criteria are used or design a wheel.
Materials to produce these wheels have become has sophisticated as a design and materials
can range from steel to nonferrous alloys like magnesium and aluminium. Automotive
wheels have evolved over the decades from early spoke designs of wood and steel. Carry
over’s from wagon and bicycle technology, to flat steel discs and finally to the stamped
metal configurations and modern cast and forged aluminium alloys rims of today’s modern
vehicles historically successful designs arrived after years of experience and extensive field
testing. Since the 1970’s several innovative methods of testing well aided with experimental
stress measurements have been initiated . In recent years, the procedures have been improved
by a variety of experimental and analytical methods for structural analysis is (strain gauge
and finite element methods). Within the past 10 years, durability analysis (fatigue life
predication) and reliability method for dealing with variations inherent in engineering
structure have been applied to the automotive wheel. Wheel rims affect the braking
performance of a vehicle as result of the following for parameters: size, weight, design or
ventilation, materials. The size of the wheel rim governs how much space there is between
the rim and the brake rotor. By moving up to a higher diameter wheel rim there will be more
scope for air flow around the brakes and therefore better cooling. The weight of the wheel
rim is an obvious issue. The mass is not only important in terms of the overall weight of the
wheel, the rotational inertia of the wheel goes up with more weight as well, causing even
more work for the brakes. The handling of a vehicle is always improved with light weight.
As in case of ride, the lighter the unsprung weights are more easily controlled in the motion
of the tire wheel and the better the adhesion to the road surface. Another factor in handling
has to do with wheel strength and flex. A more rigid wheel will reduced wheel flex during
cohering and improve tire performance. This is especially important with low aspect ratio,
high performance tires that can be generate high cornering forces. Car wheels are divided in
to two main groups, steel wheels and alloy wheels. Alloy wheels are frequently fitted typical
during the manufacturing of modern vehicles. All steel wheels to be made up of two pressed
components, the rim and the wheel disc, which are joined (welded) together.
3.Theory of Wheels
The tire works as a wheel only after it is set up on the rim and is inflated therefore;
the tire and wheel assembly effects the function and performance of the vehicle. The tire is
designed and manufactured to suit a usual rim and once installed on the correct rim the tire
will perform up to its preferred level. It is needless to say that the life of the tire will be
reduced if it is installed on an unsuitable rim. The rim is actually the name for the cylindrical
part where the tire is installed. A wheel is the name for grouping between rim and disc plate.
Once the disc plate is fixed inside the cylinder this assembly becomes a wheel.
3.1 Rim Nomenclature
1. Wheel: Wheel is generally composed of rim and disc.
2. Rim: This is a part where the tire is installed.
3. Disc: This is a part of the rim where it is fixed to the axle hub.
4. Offset: This is a space between wheel mounting surface where it is bolted to hub
and centre line of rim.
5. Flange: The flange is a part of rim which holds the both beds of the tire.
6. Bead Seat: Bead seat approaches in contact with the bead face and it is a part of rim
which holds the tire in a radial direction.
7. Hump: It is a bump what was put on the bed seat for the bead to prevent the tire
from sliding off the rim while the vehicle is moving.
8. Well: This is a part of rim with depth and width to facilitate tire mounting and
removal from the rim.
3.2 Type of Wheel/Rim: (Dimensional)
3.2.1 Shape of Rim
Typical rim shape vehicles are made up of the following.
a) Drop centre rim (DC)
Drop centre rim (DC rim) is shaped so there is fine between the bead seat parts
which is placed on both sides of the rim. This is to make the mounting and
dismounting of the tire easy. In most circumstances there is a taper of 5 degrees in the
bead seat area.
b)Wide drop centre rim (WDC)
Wide drop centre (WDC rim) is mostly the same as DC rim. To
expand the width of the rim, with a slighter well and a lower flange height,
this rim is mostly applied to low aspect ratio tires. This design is presently
applied to rims for tires of most passenger vehicles.
c) Wide Drop Centre Rim With Hump
In addition, this design has a bump, on the beginning of the bead seat
area. This hump is to prevent the bead sliding down and air outflow from the
rim due to the horizontal force applied to the tire when a vehicle tubeless tires
runs at high speed.
3.2.2 Types of Wheel/Rim (Material)
Steel and light alloy are the foremost materials used in a wheel rim however
some composite materials together with glass-fibre are being used for special wheels.
a) Wire Spoke Wheel
Wire spoke wheel is an essential where the exterior edge part of the wheel (rim)
and the axle mounting part are linked by numerous wires called spokes. Today’s
automobiles with their high horsepower have made this type of wheel
manufacture obsolete. This type of wheel is still used on classic vehicles. Light
alloy wheels have developing in recent years, a design to give emphasis to this
spoke effect to fulfil users fashion requirements.
b) Steel Disc Wheel
This is a rim which practices the steel-made rim and the wheel into one by
joining (welding), and it is used mainly for passenger vehicles especially original
equipment tires.
c) Light Alloy Wheel
These wheels are based on the use of light metals, such as aluminium and
magnesium has come to be popular in the market. This wheel rapidly become
standard for the original equipment vehicle in Europe in 1960’s and for the
replacement tire in United States in 1970’s. The advantages of each light alloy
wheel are explained as below.
i. Aluminium Alloy Wheel
Aluminium is a metal with features of excellent lightness, thermal
conductivity, rust confrontation, physical characteristics of casting, low heat, machine
processing and reutilizing, etc. This metals main advantage is decreased weight, high
precision and design choices of the wheel. This metal is useful for energy
preservation because it is possible to re-cycle aluminium easily.
ii. Magnesium alloy wheel
Magnesium is about 30% lighter than aluminium and also admirable as for
size stability and impact resistance. However, its use is mainly restricted to racing,
which needs the features of weightlessness and high strength at the expense of
weathering resistance and design choice, etc. Compared with aluminium.
iii. Titanium alloy wheel
Titanium is an admirable metal for corrosion resistance and strength (about
2.5 times) compared with aluminium, but it is inferior due to machine processing,
designing and more cost. It is still in the development stage even though there is some
use in the field of racing.
iv. Composite material wheel
The composite material wheel is different from the light alloy wheel, and it
is developed mainly for low weight. However this wheel has inadequate consistency
against heat and for best strength. Development is continuing.
4. Modelling of Wheel Rim
SOLID WORKS is software which is used for creation and modifications of the objects.
In SOLID WORKS and design and modelling feature is available. Design means the process
of creating a new object or modifying the existing one. Drafting means the representation or
idea of the object. Modelling means create and converting 2D to 3D. By using SOLID
WORKS software, create the model of the wheel rim.
Specifications of Model Wheel Rim
Tire diameter (approx.) = 560 mm
Wheel size = 14 inches
Length = 86 mm
Flange shape = J Rim
width = 5 inches
Wheel type = disc wheel
Flange height = 0.68 inches
Tire type = radial
Aspect ratio = 65
Offset = 80.54
4.1 Steps Involved In Design
1. Draw the profile diagram of the wheel rim.
2. Now use revolve command the profile body with respect to y-axis. then we obtain
the wheel rim.
3. By selecting the face of wheel, the required design is drawn on the surface.
4. By using circular pattern the specific design is obtained all over the rim.
5. Once again selecting the face draw the circle for and rotate them using circular
pattern.
6. From holes using sketch of center circle option.
7. And finally using the EDGE FILLET option the side edges are made filleted for
final finishing.
4.2 Final view of wheel rim
5. Result Analysis
1. After preparing the model in SOLID WORKS it is improved to ANSYS.
2. The imported model is meshed by using TETRA mesh. the meshed model is as
follows:
3. Later this meshed model is defined with two different materials namely
ALUMINIUM and FORGED STEEL and subjected to static analysis.
5.1 AT PREPROCESSOR STAGE:
Input data for ALUMINIUM:
Young’s modulus: 0.71e5N/mm²
Poisson’s ratio = 0.33
Density = 2800kg/m³
Circumferential pressure = 200 kpa
Input data for FORGED STEEL:
Young’s modulus: 2.1e5N/mm²
Poisson’s ratio = 0.3
Density = 7600kg/m³
Circumferential pressure = 200 kpa
1. After this meshed model is constrained at holes by all DOF where the bolts has to
be placed.
2. After constraining the meshed model, the model is subjected to a circumferential
load of 200 kpa.
3. Later the results were obtained in the SOLVER module.
4. Later in the SOLVER module, analysis type is changed from static command to
modal command and solution in done in solution window.
5. Next solution results such as stress, displacement, von mises, ultimate strength etc.,
it can be observed in GENERALPOST-PROCESSOR.
Conclusion and future work:
CAD model of the wheel rim is generated in CATIA and this model is imported to
ANSYS for processing work. An amount of pressure 200 kpa is applied along the
circumference of the wheel rims made of both ALUMINIUM & FORGED STEEL
and bolt circle of wheel rim is fixed. Following are the conclusions from the results
obtained:
Aluminium wheel rim is subjected to more stress compared to Forged steel.
In both cases von-mises stresses are less than ultimate strength.
Deflections in aluminium are more when compared to forged steel.
Since in both the cases von-mises stresses is less than the ultimate strength,
talking deflections into account, forged steel is preferred as best material for
designed wheel rim.
6.1Scope for Future Work
In the above proposed work only pressure acting circumferentially on the
wheel rim is only considered, this can be extended to other forces that act on the
wheel rim and structural analysis is carried out, this can be extended to transient
analysis.