MATERIAL OPTIMIZATION OF FLYWHEEL IN IC ENGINE

PROJECT REPORT 2011-2012

Submitted by

(Team name)

Guided by:

Submitted in partial fulfillment of the requirement for the

Award of Diploma in -----------------------------------------

By the State Board of Technical Education Government of

Tamilnadu, Chennai.

DEPARTMENT:

COLLEGE NAME:

COLLEGE LOGO

PLACE:

COLLEGE NAME

PLACE

DEPARTMENT

PROJECT REPORT-2011-2012

This Report is certified to be the Bonafide work done by

Selvan/Selvi ---------------- Reg.No. ------------ Of VI Semester

class of this college.

Guide Head of the Department

Submitted for the Practical Examinations of the board of

Examinations,State Board of Technical Education,Chennai,

TamilNadu.On -------------- (date) held at the ------------

(college name),Coimbatore

Internal Examiner External Examiner

ACKNOWLEDGEMENT

At this pleasing movement of having successfully

completed our project, we wish to convey our sincere thanks

and gratitude to the management of our college and our

beloved chairman------------------------.who provided all the

facilities to us.

We would like to express our sincere thanks to our

principal ------------------for forwarding us to do our project and

offering adequate duration in completing our project.

We are also grateful to the Head of Department

prof…………., for her/him constructive suggestions

&encouragement during our project.

With deep sense of gratitude, we extend our earnest

&sincere thanks to our guide --------------------, Department of

Mechanical for her/him kind guidance and encouragement

during this project we also express our indebt thanks to our

TEACHING staff of MECHANICAL ENGINEERING DEPARTMENT,

---------- (college Name).

CONTENTS

CHAPTER

NO

TITLE

SYNOPSIS

1 INTRODUCTION

2 COMPOSITE MATERIALS

3 PRO-E & ANSYS

4 MODELLING COMMANDS USED IN PRO-E

5 ANALYSIS PROCEDURE

6 MATERIAL PROPERTIES

7 RESULTS

8 CONCLUSION

REFERENCE

SYNOPSIS

In this project we are doing the material optimization of flywheel

in an internal combustion engine. This project we are designed the

3D model of the flywheel by using pro-e software and the analysis

taken by different materials and also change the thickness and other

design parameters of the flywheel and the analysis taken by the

ansys software.

This project we are analyzed the rotational velocity and moment

acting on the flywheel by the three materials. Presently the flywheels

are made by the material of cast iron, this project we are testing the

same load under the three materials. The materials are cast iron, high

strength epoxy carbon and duralumin.

CHAPTER-I

INTRODUCTION

INTRODUCTION TO FLYWHEEL

A flywheel is a mechanical device with a significant moment of

inertia used as a storage device for rotational energy. Flywheels

resist changes in their rotational speed, which helps steady the

rotation of the shaft when a fluctuating torque is exerted on it by its

power source such as a piston-based (reciprocating) engine, or when

an intermittent load, such as a piston pump, is placed on it. Flywheels

can be used to produce very high power pulses for experiments,

where drawing the power from the public network would produce

unacceptable spikes.

FLYWHEEL IN THE INTERNAL COMBUSTION ENGINE

For internal combustion engine applications, the flywheel is a

heavy wheel mounted on the crankshaft. Its main function is to

maintain a fairly constant angular velocity of the crankshaft.

ADVANTAGES OF OPTIMIZATION OF THE FLYWHEEL

Avoid the deformation of flywheel in short time

Improve the performance of the flywheel by using alternate

materials

Increase the lifecycle of the flywheel

USES OF COMPOSITE FLYWHEELS

The faster we can spin a flywheel and the more massive we

can make it, the flywheel, and the more kinetic energy we can store in

it. However, at extreme speeds, even metal flywheels can literally

tear themselves apart from the shear forces which are generated.

Further, the energy storage characteristics of the flywheel are

influenced more strongly by its maximal rotational velocity than by its

mass.

MANUFACTURING OF COMPOSITE FLYWHEEL:

The flywheel rim and arbors are constructed using a

combination of Toray M30S intermediate modulus graphite, Toray

T700 standard modulus graphite, and Owens-Corning S2 fiberglass

(Table) the resin is a Fiberite 977-2 thermosetting epoxy resin system

toughened with thermoplastic additives.

IMPORTANCE OF EPOXY

Epoxy is a prominent resin used in manufacture of composite

flywheel.

MERITS OF COMPOSITE FLYWHEEL

· Compact

· Energy storage system more efficient

· Less weight

· Long life

· High efficiency

· Low maintenance

· No aerodynamic noise

DEMERITS

· Safety concerns

· High material costs

Expensive magnetic bearing

APPLICATIONS OF COMPOSITE FLYWHEEL

Composite Flywheels are not only used for Electric Vehicles

and Hybrid Electric but it also finds space applications.

ENERGY STORED IN FLYWHEEL

When flywheel absorbs energy as in the case of internal

combustion engines, velocity increases and the stored energy is

given out, the velocity or speed diminishes.

Total kinetic energy E = i ω 2 /2

i = mass moment of inertia of flywheel about the axis of rotation in

KgMts2.

ω = mean angular speed of the flywheel in Rad/ sec.

i = MK2 For rim type.

i = MK2 / 2 for disc type.

K = Radius of gyration of flywheel in mts.

M = Mass of fly wheel in kgs.

FLUCTUATION OF ENERGY

If the velocity of flywheel changes, energy it will absorb or gives

up is proportional to the difference between the initial and final

speeds, and is equal to the difference between the initial and final

speeds, and is equal to the difference between energies which could

give out, if brought to a full stop position that which is still stored in it

at the reduced velocity.

E1 = E D = MAXke - MINke

= i ω12 /2 - i ω2

2 /2

= i / 2 (ω12 - ω2

2 )

= i / 2(ω1 - ω 2) x (ω1 + ω2)

= i x ω (ω1 - ω2) ω= (ω1 + ω2)/2

= i x ω 2 (ω1 - ω2 )/ω

E1 = E = i x ω2 x Cs

R = Mean radius of rim.

Cs = Co-efficient of fluctuating speed.

K = Radiation of gyration.

K = R (Assumption)

E1 = E = Fluctuation of energy.

ω = Mean angular velocity of flywheel.

M = Mass of flywheel rim.

CHAPTER-II

COMPOSITE MATERIALS

COMPOSITE MATERIALS

A typical composite material is a system of materials composing

of two or more materials (mixed and bonded) on a macroscopic

scale. For example, concrete is made up of cement, sand, stones,

and water. If the composition occurs on a microscopic scale

(molecular level), the new material is then called an alloy for metals

or a polymer for plastics.

Generally, a composite material is composed of reinforcement

(fibers, particles, flakes, and/or fillers) embedded in a matrix

(polymers, metals, or ceramics). The matrix holds the reinforcement

to form the desired shape while the reinforcement improves the

overall mechanical properties of the matrix. When designed properly,

the new combined material exhibits better strength than would each

individual material.

COMPOSITE THEORY

In its most basic form a composite material is one, which is

composed of at least two elements working together to produce

material properties that are different to the properties of those

elements on their own. In practice, most composites consist of a bulk

material (the ‘matrix’), and a reinforcement of some kind, added

primarily to increase the strength and stiffness of the matrix. This

reinforcement is usually in fibre form. Today, the most common man-

made composites can be divided into three main groups:

·         Polymer Matrix Composites (PMC’s) – These are the most

common and will be discussed here. Also known as FRP - Fibre

Reinforced Polymers (or Plastics) – these materials use a polymer-

based resin as the matrix, and a variety of fibres such as glass,

carbon and aramid as the reinforcement.

·         Metal Matrix Composites (MMC’s) - Increasingly found in the

automotive industry, these materials use a metal such as aluminium

as the matrix, and reinforce it with fibres such as silicon carbide.

·         Ceramic Matrix Composites (CMC’s) - Used in very high

temperature environments, these materials use a ceramic as the

matrix and reinforce it with short fibres, or whiskers such as those

made from silicon carbide and boron nitride.

POLYMER MATRIX COMPOSITES

Resin systems such as epoxies and polyesters have limited use

for the manufacture of structures on their own, since their mechanical

properties are not very high when compared to, for example, most

metals. However, they have desirable properties, most notably their

ability to be easily formed into complex shapes. Materials such as

glass, aramid and boron have extremely high tensile and

compressive strength but in ‘solid form’ these properties are not

readily apparent. This is due to the fact that when stressed, random

surface flaws will cause each material to crack and fail well below its

theoretical ‘breaking point’. To overcome this problem, the material is

produced in fibre form, so that, although the same number of random

flaws will occur, they will be restricted to a small number of fibres with

the remainder exhibiting the material’s theoretical strength. Therefore

a bundle of fibres will reflect more accurately the optimum

performance of the material. However, fibres alone can only exhibit

tensile properties along the fibre’s length, in the same way as fibres in

a rope.

It is when the resin systems are combined with reinforcing

fibres such as glass, carbon and aramid that exceptional properties

can be obtained. The resin matrix spreads the load applied to the

composite between each of the individual fibres and also protects the

fibres from damage caused by abrasion and impact. High strengths

and stiffnesses, ease of moulding complex shapes, high

environmental resistance all coupled with low densities, make the

resultant composite superior to metals for many applications. Since

PMC’s combine a resin system and reinforcing fibres, the properties

of the resulting composite material will combine something of the

properties of the resin on its own with that of the fibres on their own,

as surmised in Figure 1.

Figure: 1 – Illustrating the combined effect on Modulus of the

addition of fibres to a resin matrix.

Overall, the properties of the composite are determined by:

·         The properties of the fibre

·         The properties of the resin

·         The ratio of fibre to resin in the composite (Fibre Volume

Fraction (FVF))

·         The geometry and orientation of the fibres in the composite

The ratio of the fibre to resin derives largely from the manufacturing

process used to combine resin with fibre. However, it is also

influenced by the type of resin system used, and the form in which

the fibres are incorporated. In general, since the mechanical

properties of fibres are much higher than those of resins, the higher

the fibre volume fraction the higher will be the mechanical properties

of the resultant composite. In practice there are limits to this, since

the fibres need to be fully coated in resin to be effective, and there

will be an optimum packing of the generally circular cross-section

fibres. In addition, the manufacturing process used to combine fibre

with resin leads to varying amounts of imperfections and air

inclusions.

Typically, with a common hand lay-up process as widely used

in the boat-building industry, a limit for FVF is approximately 30-40%.

With the higher quality, more sophisticated and precise processes

used in the aerospace industry, FVF’s approaching 70% can be

successfully obtained.

The geometry of the fibres in a composite is also important

since fibres have their highest mechanical properties along their

lengths, rather than across their widths. This leads to the highly

anisotropic properties of composites, where, unlike metals, the

mechanical properties of the composite are likely to be very different

when tested in different directions. This means that it is very

important when considering the use of composites to understand at

the design stage, both the magnitude and the direction of the applied

loads. When correctly accounted for, these anisotropic properties can

be very advantageous since it is only necessary to put material where

loads will be applied, and thus redundant material is avoided.

It is also important to note that with metals the material supplier

largely determines the properties of the materials, and the person

who fabricates the materials into a finished structure can do almost

nothing to change those ‘in-built’ properties. However, a composite

material is formed at the same time, as the structure is itself being

fabricated. This means that the person who is making the structure is

creating the properties of the resultant composite material, and so the

manufacturing processes they use have an unusually critical part to

play in determining the performance of the resultant structure.

LOADING

There are four main direct loads that any material in a structure has

to withstand: tension, compression, shear and flexure.

TENSION

Figure 2 shows a tensile load applied to a composite. The response of a composite

to tensile loads is very dependent on the tensile stiffness and strength properties of the

reinforcement fibres, since these are far higher than the resin system on its own.

Figure 2 – Illustrates the tensile load applied to a composite body.

COMPRESSION

Figure 3 shows a composite under a compressive load. Here, the adhesive and

stiffness properties of the resin system are crucial, as it is the role of the resin to maintain

the fibres as straight columns and to prevent them from buckling.

Figure 3 - Illustrates the compression load applied to a composite

body.

SHEAR

Figure 4 shows a composite experiencing a shear load. This load is trying to slide

adjacent layers of fibres over each other. Under shear loads the resin plays the major role,

transferring the stresses across the composite. For the composite to perform well under

shear loads the resin element must not only exhibit good mechanical properties but must

also have high adhesion to the reinforcement fibre. The interlaminar shear strength

(ILSS) of a composite is often used to indicate this property in a multiplayer composite

(‘laminate’).

Figure 4 - Illustrates the shear load applied to a composite body.

FLEXURE

Flexural loads are really a combination of tensile, compression and shear loads.

When loaded as shown (Figure 5), the upper face is put into compression, the lower face

into tension and the central portion of the laminate experiences shear.

Figure 5 - Illustrates the loading due to flexure on a composite

body.

COMPARISON WITH OTHER STRUCTURAL MATERIALS

Due to the factors described above, there is a very large range

of mechanical properties that can be achieved with composite

materials. Even when considering one fibre type on its own, the

composite properties can vary by a factor of 10 with the range of fibre

contents and orientations that are commonly achieved. The

comparisons that follow therefore show a range of mechanical

properties for the composite materials. The lowest properties for each

material are associated with simple manufacturing processes and

material forms (e.g. spray lay-up glass fibre), and the higher

properties are associated with higher technology manufacture (e.g.

autoclave moulding of unidirectional glass fibre prepreg), such as

would be found in the aerospace industry.

For the other materials shown, a range of strength and stiffness (modulus) figures are

also given to indicate the spread of properties associated with different alloys, for example.

Figure 6 – Tensile Strength of Common Structural Materials

Figure 7 – Tensile Modulus of Common Structural Materials

The above Figures (6 and 7) clearly show the range of properties that different

composite materials can display. These properties can best be summed up as high strengths and

stiffnesses combined with low densities. It is these properties that give rise to the characteristic

high strength and stiffness to weight ratios that make composite structures ideal for so many

applications. This is particularly true of applications, which involve movement, such as cars,

trains and aircraft, since lighter structures in such applications play a significant part in making

these applications more efficient. The strength and stiffness to weight ratio of composite

materials can best be illustrated by the following graphs that plot ‘specific’ properties. These are

simply the result of dividing the mechanical properties of a material by its density. Generally, the

properties at the higher end of the ranges illustrated in the previous graphs (Figures 6 and 7) are

produced from the highest density variant of the material. The spread of specific properties

shown in the following graphs (Figures 8 and 9) takes this into account.

Figure 8 – Specific Tensile Strength of Common Structural

Materials

Figure 9 - Specific Tensile Modulus of Common Structural Materials

COMMON CATEGORIES OF COMPOSITE MATERIALS

Based on the form of reinforcement, common composite

materials can be classified as follows:

1. Fibers as the reinforcement (Fibrous Composites):

  a. Random fiber (short fiber) reinforced composites

  b. Continuous fiber (long fiber) reinforced composites

2. Particles as the reinforcement (Particulate composites):

3. Flat flakes as the reinforcement (Flake composites):

4. Fillers as the reinforcement (Filler composites):

BENEFITS OF COMPOSITES

Different materials are suitable for different applications. When

composites are selected over traditional materials such as metal

alloys or woods, it is usually because of one or more of the following

advantages:

COST

o Prototypes

o Mass production

o Part consolidation

o Maintenance

o Long term durability

o Production time

o Maturity of technology

WEIGHT

o Light weight

o Weight distribution

STRENGTH AND STIFFNESS

o High strength-to-weight ratio

o Directional strength and/or stiffness

DIMENSION

o Large parts

o Special geometry

SURFACE PROPERTIES

o Corrosion resistance

o Weather resistance

o Tailored surface finish

THERMAL PROPERTIES

o Low thermal conductivity

o Low coefficient of thermal expansion

ELECTRIC PROPERTY

o High dielectric strength

o Non-magnetic

o Radar transparency

Note that there is no one-material-fits-all solution in the

engineering world. Also, the above factors may not always be positive

in all applications. An engineer has to weigh all the factors and make

the best decision in selecting the most suitable material(s) for the

project at hand.

HISTORYOF COMPOSITE MATERIALS

Wood is a natural composite of cellulose fibers in a matrix of

lignin. The most primitive manmade composite materials were straw

and mud combined to form bricks for building construction; the

Biblical Book of Exodus speaks of the Israelites being oppressed by

Pharaoh, by being forced to make bricks without straw being

provided. The ancient brick-making process can still be seen on

Egyptian tomb paintings in the Metropolitan Museum of Art. The most

advanced examples perform routinely on spacecraft in demanding

environments. The most visible applications pave our roadways in the

form of either steel and aggregate reinforced portland cement or

asphalt concrete. Those composites closest to our personal hygiene

form our shower stalls and bath tubs made of fiberglass. Solid

surface, imitation granite and cultured marble sinks and counter tops

are widely used to enhance our living experiences.

Composites are made up of individual materials referred to as

constituent materials. There are two categories of constituent

materials: matrix and reinforcement. At least one portion of each type

is required. The matrix material surrounds and supports the

reinforcement materials by maintaining their relative positions. The

reinforcements impart their special mechanical and physical

properties to enhance the matrix properties. A synergism produces

material properties unavailable from the individual constituent

materials, while the wide variety of matrix and strengthening materials

allows the designer of the product or structure to choose an optimum

combination.

Engineered composite materials must be formed to shape. The

matrix material can be introduced to the reinforcement before or after

the reinforcement material is placed into the mold cavity or onto the

mold surface. The matrix material experiences a melding event, after

which the part shape is essentially set. Depending upon the nature of

the matrix material, this melding event can occur in various ways

such as chemical polymerization or solidification from the melted

state.

A variety of molding methods can be used according to the

end-item design requirements. The principal factors impacting the

methodology are the natures of the chosen matrix and reinforcement

materials. Another important factor is the gross quantity of material to

be produced. Large quantities can be used to justify high capital

expenditures for rapid and automated manufacturing technology.

Small production quantities are accommodated with lower capital

expenditures but higher labor and tooling costs at a correspondingly

slower rate.

Most commercially produced composites use a polymer matrix

material often called a resin solution. There are many different

polymers available depending upon the starting raw ingredients.

There are several broad categories, each with numerous variations.

The most common are known as polyester, vinyl ester, epoxy,

phenolic, polyimide, polyamide, polypropylene, PEEK, and others.

The reinforcement materials are often fibers but also commonly

ground minerals. The various methods described below have been

developed to reduce the resin content of the final product, or the fibre

content is increased. As a rule of thumb, lay up results in a product

containing 60% resin and 40% fibre, whereas vacuum infusion gives

a final product with 40% resin and 60% fibre content. The strength of

the product is greatly dependent on this ratio.

FAILURE OF COMPOSITE MATERIALS

Shock, impact, or repeated cyclic stresses can cause the

laminate to separate at the interface between two layers, a condition

known as delamination. Individual fibers can separate from the matrix

e.g. fiber pull-out. Composites can fail on the microscopic or

macroscopic scale. Compression failures can occur at both the macro

scale or at each individual reinforcing fiber in compression buckling.

Tension failures can be net section failures of the part or degradation

of the composite at a microscopic scale where one or more of the

layers in the composite fail in tension of the matrix or failure the bond

between the matrix and fibers.

Some composites are brittle and have little reserve strength

beyond the initial onset of failure while others may have large

deformations and have reserve energy absorbing capacity past the

onset of damage. The variations in fibers and matrices that are

available and the mixtures that can be made with blends leave a very

broad range of properties that can be designed into a composite

structure. The best known failure of a brittle ceramic matrix composite

occurred when the carbon-carbon composite tile on the leading edge

of the wing of the Space Shuttle Columbia fractured when impacted

during take-off. It led to catastrophic break-up of the vehicle when it

re-entered the Earth's atmosphere on February 1, 2003. Compared to

metals, composites have relatively poor bearing strength.

TESTING OF COMPOSITE MATERIALS

To aid in predicting and preventing failures, composites are

tested before and after construction. Pre-construction testing may use

finite element analysis (FEA) for ply-by-ply analysis of curved

surfaces and predicting wrinkling, crimping and dimpling of

composites. Materials may be tested after construction through

several nondestructive methods including ultrasonics, thermography,

shearography and X-ray radiography.

PRODUCTS MADE BY THE COMPOSITES

Composite materials have gained popularity (despite their

generally high cost) in high-performance products that need to be

lightweight, yet strong enough to take harsh loading conditions such

as aerospace components (tails, wings, fuselages, propellers), boat

and scull hulls, bicycle frames and racing car bodies. Other uses

include fishing rods, storage tanks, and baseball bats. The new

Boeing 787 structure including the wings and fuselage is composed

largely of composites. Composite materials are also becoming more

common in the realm of orthopedic surgery.

Carbon composite is a key material in today's launch vehicles

and spacecraft. It is widely used in solar panel substrates, antenna

reflectors and yokes of spacecraft. It is also used in payload

adapters, inter-stage structures and heat shields of launch vehicles.

In 2007 an all-composite military High Mobility Multi-purpose

Wheeled Vehicle (HMMWV or Hummvee) was introduced by TPI

Composites Inc and Armor Holdings Inc, the first all-composite

military vehicle. By using composites the vehicle is lighter, allowing

higher payloads. In 2008 carbon fiber and DuPont Kevlar (five times

stronger than steel) were combined with enhanced thermoset resins

to make military transit cases by ECS Composites creating 30-

percent lighter cases with high strength.

LOAD TRANSFER IN A COMPOSITE MATERIALS

The concept of load sharing between the matrix and the reinforcing constituent

(fibre) is central to an understanding of the mechanical behaviour of a composite. An

external load (force) applied to a composite is partly borne by the matrix and partly by

the reinforcement. The load carried by the matrix across a section of the composite is

given by the product of the average stress in the matrix and its sectional area. The load

carried by the reinforcement is determined similarly. Equating the externally imposed

load to the sum of these two contributions, and dividing through by the total sectional

area, gives a basic and important equation of composite theory, sometimes termed the

"Rule of Averages".

(1)

which relates the volume-averaged matrix and fibre stresses ( ),

in a composite containing a volume (or sectional area) fraction f of

reinforcement, to the applied stress sA. Thus, a certain proportion of

an imposed load will be carried by the fibre and the remainder by the

matrix. Provided the response of the composite remains elastic, this

proportion will be independent of the applied load and it represents

an important characteristic of the material. It depends on the volume

fraction, shape and orientation of the reinforcement and on the elastic

properties of both constituents. The reinforcement may be regarded

as acting efficiently if it carries a relatively high proportion of the

externally applied load. This can result in higher strength, as well as

greater stiffness, because the reinforcement is usually stronger, as

well as stiffer, than the matrix.

What happens when a Composite is Stressed?

Figure 1

Consider loading a composite parallel to the fibres. Since they are

bonded together, both fibre and matrix will stretch by the same

amount in this direction, i.e. they will have equal strains, e (Fig. 1).

This means that, since the fibres are stiffer (have a higher Young

modulus, E), they will be carrying a larger stress. This illustrates the

concept of load transfer, or load partitioning between matrix and

fibre, which is desirable since the fibres are better suited to bear high

stresses. By putting the sum of the contributions from each phase

equal to the overall load, the Young modulus of the composite is

found (diagram). It can be seen that a "Rule of Mixtures" applies.

This is sometimes termed the "equal strain" or "Voigt" case. Page

2 in the section covers derivation of the equation for the axial stiffness

of a composite and page 3 allows the effects on composite stiffness

of the fibre/matrix stiffness ratio and the fibre volume fraction to be

explored by inputting selected values.

What about the Transverse Stiffness?

Also of importance is the response of the composite to a load applied

transverse to the fibre direction. The stiffness and strength of the

composite are expected to be much lower in this case, since the

(weak) matrix is not shielded from carrying stress to the same degree

as for axial loading. Prediction of the transverse stiffness of a

composite from the elastic properties of the constituents is far more

difficult than the axial value. The conventional approach is to assume

that the system can again be represented by the "slab model". A

lower bound on the stiffness is obtained from the "equal stress" (or

"Reuss") assumption shown in Fig. 2. The value is an

underestimate, since in practice there are parts of the matrix

effectively "in parallel" with the fibres (as in the equal strain model),

rather than "in series" as is assumed. Empirical expressions are

available which give much better approximations, such as that of

Halpin-Tsai. There are again two pages in the section covering this topic, the first

(page 4) outlining derivation of the equal stress equation for stiffness and the second

(page 5) allowing this to be evaluated for different cases. For purposes of comparison, a

graph is plotted of equal strain, equal stress and Halpin-Tsai predictions. The Halpin-Tsai

expression for transverse stiffness (which is not given in the module, although it is

available in the glossary) is:

(2)

in which

Figure 2

The value of x may be taken as an adjustable parameter, but its

magnitude is generally of the order of unity. The expression gives the

correct values in the limits of f=0 and f=1 and in general gives good

agreement with experiment over the complete range of fibre content.

A general conclusion is that the transverse stiffness (and strength) of

an aligned composite are poor; this problem is usually countered by

making a laminate (see section on "composite laminates").

How is Strength Determined?

There are several possible approaches to prediction of the strength of

a composite. If the stresses in the two constituents are known, as for

the long fiber case under axial loading, then these values can be

compared with the corresponding strengths to determine whether

either will fail. Page 6 in the section briefly covers this concept. (More

details about strength are given in the section on "Fracture

Behavior".) The treatment is a logical development from the analysis

of axial stiffness, with the additional input variable of the ratio

between the strengths of fiber and matrix.

Such predictions are in practice complicated by uncertainties

about in situ strengths, interfacial properties, residual stresses

etc. Instead of relying on predictions such as those outlined above, it

is often necessary to measure the strength of the composite, usually

by loading parallel, transverse and in shear with respect to the fibres.

This provides a basis for prediction of whether a component will fail

when a given set of stresses is generated (see section on "Fracture

Behaviour"), although in reality other factors such as environmental

degradation or the effect of failure mode on toughness, may require

attention.

What happens with Short Fibres?

Short fibres can offer advantages of economy and ease of

processing. When the fibres are not long, the equal strain condition

no longer holds under axial loading, since the stress in the fibres

tends to fall off towards their ends (see Fig. 3). This means that the

average stress in the matrix must be higher than for the long fiber

case. The effect is illustrated pictorially in pages 7 and 8 of the

section.

Figure 3

This lower stress in the fibre, and correspondingly higher

average stress in the matrix (compared with the long fibre case) will

depress both the stiffness and strength of the composite, since the

matrix is both weaker and less stiff than the fibres. There is therefore

interest in quantifying the change in stress distribution as the fibres

are shortened. Several models are in common use, ranging from

fairly simple analytical methods to complex numerical packages. The

simplest is the so-called "shear lag" model. This is based on the

assumption that all of the load transfer from matrix to fibre occurs via

shear stresses acting on the cylindrical interface between the two

constituents. The build-up of tensile stress in the fibre is related to

these shear stresses by applying a force balance to an incremental

section of the fibre. This is depicted in page 9 of the section. It leads

to an expression relating the rate of change of the stress in the fibre

to the interfacial shear stress at that point and the fibre radius, r.

(3)

which may be regarded as the basic shear lag relationship. The

stress distribution in the fibre is determined by relating shear strains

in the matrix around the fibre to the macroscopic strain of the

composite. Some mathematical manipulation leads to a solution for

the distribution of stress at a distance x from the mid-point of the fibre which

involves hyperbolic trig functions:

(4)

where e1 is the composite strain, s is the fibre aspect ratio

(length/diameter) and n is a dimensionless constant given by:

 

(5)

in which nm is the Poisson ratio of the matrix. The variation of

interfacial shear stress along the fibre length is derived, according to

Eq.(3), by differentiating this equation, to give:

 

(6)

The equation for the stress in the fibre, together with the assumption

of a average tensile strain in the matrix equal to that imposed on the

composite, can be used to evaluate the composite stiffness. This

leads to:

 (7)

The expression in square brackets is the composite stiffness. In

page 10 of the section, there is an opportunity to examine the

predicted stiffness as a function of fibre aspect ratio, fibre/matrix

stiffness ratio and fibre volume fraction. The other point to note about

the shear lag model is that it can be used to examine inelastic

behaviour. For example, interfacial sliding (when the interfacial shear

stress reaches a critical value) or fibre fracture (when the tensile

stress in the fibre becomes high enough) can be predicted. As the

strain imposed on the composite is increased, sliding spreads along

the length of the fibre, with the interfacial shear stress unable to rise

above some critical value, ti*. If the interfacial shear stress becomes

uniform at ti* along the length of the fibre, then a critical aspect ratio,

s*, can be identified, below which the fibre cannot undergo fracture.

This corresponds to the peak (central) fibre stress just attaining its

ultimate strength sf*, so that, by integrating Eq.(3) along the fibre half-length:

(8)

It follows from this that a distribution of aspect ratios between s*

and s*/2 is expected, if the composite is subjected to a large strain.

The value of s* ranges from over 100, for a polymer composite with

poor interfacial bonding, to about 2-3 for a strong metallic matrix. In

page 10, the effects of changing various parameters on the

distributions of interfacial shear stress and fibre tensile stress can be

explored and predictions made about whether fibres of the specified

aspect ratio can be loaded up enough to cause them to fracture.

Composite Laminates

High stiffness and strength usually require a high proportion of

fibres in the composite. This is achieved by aligning a set of long

fibres in a thin sheet (a lamina or ply). However, such material is

highly anisotropic, generally being weak and compliant (having a

low stiffness) in the transverse direction. Commonly, high strength

and stiffness are required in various directions within a plane. The

solution is to stack and weld together a number of sheets, each

having the fibres oriented in different directions. Such a stack is

termed a laminate. An example is shown in the diagram. The

concept of a laminate, and a pictorial illustration of the way that the

stiffness becomes more isotropic as a single ply is made into a

cross-ply laminate, are presented in page 1 of this section.

What are the Stresses within a Crossply Laminate?

The stiffness of a single ply, in either axial or transverse

directions, can easily be calculated. (See the section on Load

Transfer). From these values, the stresses in a crossply laminate,

when loaded parallel to the fibre direction in one of the plies, can

readily be calculated. For example, the slab model can be applied to

the two plies in exactly the same way as it was applied in the last

section to fibres and matrix. This allows the stiffness of the laminate

to be calculated. This gives the strain (experienced by both plies) in

the loading direction, and hence the average stress in each ply, for a

given applied stress. The stresses in fibre and matrix within each ply

can also be found from these average stresses and a knowledge of

how the load is shared. In page 2 of this section, by inputting values

for the fibre/matrix stiffness ratio and fibre content, the stresses in

both plies, and in their constituents, can be found. Note that,

particularly with high stiffness ratios, most of the applied load is borne

by the fibres in the "parallel" ply (the one with the fibre axis parallel to

the loading axis).

What is the Off-Axis Stiffness of a Ply?

For a general laminate, however, or a crossply loaded in some

arbitrary direction, a more systematic approach is needed in order to

predict the stiffness and the stress distribution. Firstly, it is necessary

to establish the stiffness of a ply oriented so the fibres lie at some

arbitrary angle to the stress axis. Secondly, further calculation is

needed to find the stiffness of a given stack. Consider first a single

ply. The stiffness for any loading angle is evaluated as follows,

considering only stresses in the plane of the ply The applied stress is

first transformed to give the components parallel and perpendicular to

the fibres. The strains generated in these directions can be calculated

from the (known) stiffness of the ply when referred to these axes.

Finally, these strains are transformed to values relative to the loading

direction, giving the stiffness.

Figure 4

These three operations can be expressed mathematically in

tensor equations. Since we are only concerned with stresses and

strains within the plane of the ply, only 3 of each (two normal and one

shear) are involved. The first step of resolving the applied stresses,

sx, sy and txy, into components parallel and normal to the fibre axis, s1,

s2 and t12 (see Fig. 4), depends on the angle, f between the loading

direction (x) and the fibre axis (1)

(9)

where the transformation matrix is given by:

(10)

in which c = cosf and s = sinf. For example, the value of s1 would be

obtained from:

(11)

Now, the elastic response of the ply to stresses parallel and

normal to the fibre axis is easy to analyse. For example, the axial and

transverse Young’s moduli (E1 and E2) could be obtained using the

slab model or Halpin-Tsai expressions (see Load Transfer section).

Other elastic constants, such as the shear modulus (G12) and

Poisson’s ratios, are readily calculated in a similar way. The

relationship between stresses and resultant strains dictated by these

elastic constants is neatly expressed by an equation involving the

compliance tensor, S, which for our composite ply, has the form:

(12)

in which, by inspection of the individual equations, it can be seen that

Application of Eq.(12), using the stresses established from Eq.

(9), now allows the strains to be established, relative to the 1 and 2

directions. There is a minor complication in applying the final stage of

converting these strains so that they refer to the direction of loading

(x and y axes). Because engineering and tensorial shear strains are not quite the same, a

slightly different transformation matrix is applicable from that used for stresses

(13)

in which,

and the inverse of this matrix is used for conversion in the reverse direction,

(14)

in which,

The final expression relating applied stresses and resultant strains can therefore be

written,

(15)

The elements of |  |, the transformed compliance tensor, are

obtained by concatenation (the equivalent of multiplication) of the

matrices | T '|-1, | S | and | T |. The following expressions are obtained

(16)

Figure 5

The final result of this rather tedious derivation is therefore quite

straightforward. Eq.(16), together with the elastic constants of the

composite when loaded parallel and normal to the fibre axis, allows

the elastic deformation of the ply to be predicted for loading at any

angle to the fibre axis. This is conveniently done using a simple

computer program. The results of such calculations can be explored

using pages 4 and 5 in this section. As an example, Fig. 5 shows the

Young's modulus for the an polyester-50% glass fibre ply as the

angle, f between fibre axis and loading direction rises from 0° to 90°.

A sharp fall is seen as f exceeds about 5-10°.

How is the Stiffness of a Laminate obtained?

Once the elastic response of a single ply loaded at an arbitrary

angle has been established, that of a stack bonded together (i.e. a

laminate) is quite easy to predict. For example, the Young's modulus

in the loading direction is given by an applied normal stress over the

resultant normal strain in that direction. This same strain will be

experienced by all of the component plies of the laminate. Since

every ply now has a known Young's modulus in the loading direction

(dependent on its fibre direction), the stress in each one can be

expressed in terms of this universal strain. Furthermore, the force

(stress times sectional area) represented by the applied stress can

also be expressed as the sum of the forces being carried by each ply.

This allows the overall Young's modulus of the laminate to be

calculated. The results of such calculations, for any selected stacking

sequence, can be explored using pages 4 and 5.

Are Other Elastic Constants Important?

There are several points of interest about how a ply changes

shape in response to an applied load. For example, the lateral

contraction (Poisson ratio, n) behaviour may be important, since in a

laminate such contraction may be resisted by other plies, setting up

stresses transverse to the applied load. Another point with fibre

composites under off-axis loading is that shear strains can arise from

tensile stresses (and vice versa). This corresponds to the elements of

S which are zero in Eq.(12) becoming non-zero for an arbitrary

loading angle (Eq.(16)). These so-called "tensile-shear

interactions" can be troublesome, since they can set up stresses

between individual plies and can cause the laminate to become

distorted. The value of , for example, represents the ratio between

g12 and s1. Its value can be obtained for any specified laminate by

using page 6 of this section. It will be seen that, depending on the

stacking sequence, relatively high distortions of this type can arise.

On the other hand, a stacking sequence with a high degree of

rotational symmetry can show no tensile-shear interactions. When the

tensile-shear interaction terms contributed by the individual laminae

all cancel each other out in this way, the laminate is said to be

"balanced". Simple crossply and angle-ply laminates are not

balanced for a general loading angle, although both will be balanced

when loaded at f=0° (i.e. parallel to one of the plies for a cross-ply or

equally inclined to the +q and -q plies for the angle-ply case). If the

plies vary in thickness, or in the volume fractions or type of fibres they

contain, then even a laminate in which the stacking sequence does

exhibit the necessary rotational symmetry is prone to tensile-shear

distortions and computation is necessary to determine the lay-up

sequence required to construct a balanced laminate. The stacking

order in which the plies are assembled does not enter into these

calculations.

How do Composites Fracture?

Figure 6

Fracture of long fibre composites tends to occur either normal

or parallel to the fibre axis. This is illustrated on page 1 of this section

- see Fig. 6. Large tensile stresses parallel to the fibres, s1, lead to

fibre and matrix fracture, with the fracture path normal to the fibre

direction. The strength is much lower in the transverse tension and

shear modes and the composite fractures on surfaces parallel to the

fibre direction when appropriate s2 or t12 stresses are applied. In these

cases, fracture may occur entirely within the matrix, at the fibre/matrix

interface or primarily within the fibre. To predict the strength of a

lamina or laminate, values of the failure stresses s1*, s2* and t12* have

to be determined.

Can the Axial Strength be Predicted?

Understanding of failure under an applied tensile stress parallel

to the fibres is relatively simple, provided that both constituents

behave elastically and fail in a brittle manner. They then experience

the same axial strain and hence sustain stresses in the same ratio as

their Young's moduli. Two cases can be identified, depending on

whether matrix or fibre has the lower strain to failure. These cases

are treated in pages 2 and 3 respectively.

Figure 7

Consider first the situation when the matrix fails first (em*<ef*).

For strains up to em*, the composite stress is given by the simple rule of mixtures:

(17)

Above this strain, however, the matrix starts to undergo

microcracking and this corresponds with the appearance of a "knee"

in the stress-strain curve. The composite subsequently extends with

little further increase in the applied stress. As matrix cracking

continues, the load is transferred progressively to the fibres. If the

strain does not reach ef* during this stage, further extension causes

the composite stress to rise and the load is now carried entirely by

the fibres. Final fracture occurs when the strain reaches ef*, so that

the composite failure stress s1* is given by f sf*. A case like this is

illustrated in Fig. 7, which refers to steel rods in a concrete matrix.

[FB2, RHS, real system data, mild steel fibres, concrete matrix, fibre

fraction 40%, "strength v. fraction of fibres" clicked]

Figure 8

Alternatively, if the fibres break before matrix cracking has become sufficiently extensive

to transfer all the load to them, then the strength of the composite is given by:

(18)

where sfm* is the fibre stress at the onset of matrix cracking (e1=em*).

The composite failure stress depends therefore on the fibre volume

fraction in the manner shown in Fig. 8. The fibre volume fraction

above which the fibres can sustain a fully transferred load is obtained

by setting the expression in Eq.(18) equal to f sf*, leading to:

(19)

If the fibres have the smaller failure strain (page 3), continued

straining causes the fibres to break up into progressively shorter

lengths and the load to be transferred to the matrix. This continues

until all the fibres have aspect ratios below the critical value (see Eq.

(8)). It is often assumed in simple treatments that only the matrix is

bearing any load by the time that break-up of fibres is complete.

Subsequent failure then occurs at an applied stress of (1-f) sm*. If

matrix fracture takes place while the fibres are still bearing some load, then the composite

failure stress is:

(20)

where smf is the matrix stress at the onset of fibre cracking. In

principle, this implies that the presence of a small volume fraction of

fibres reduces the composite failure stress below that of the

unreinforced matrix. This occurs up to a limiting value f ' given by

setting the right hand side of Eq.(20) equal to (1-f) sm*.

(21)

The values of these parameters can be explored for various systems

using pages 2 and 3. Prediction of the values of s2* and t12* from

properties of the fibre and matrix is virtually impossible, since they are

so sensitive to the nature of the fibre-matrix interface. In practice,

these strengths have to be measured directly on the composite

material concerned.

How do Plies Fail under Off-axis Loads?

Failure of plies subjected to arbitrary (in-plane) stress states can be

understood in terms of the three failure mechanisms (with defined

values of s1*, s2* and t12*) which were depicted on page 1. A number of

failure criteria have been proposed. The main issue is whether or

not the critical stress to trigger one mechanism is affected by the

stresses tending to cause the others - i.e. whether there is any

interaction between the modes of failure. In the simple maximum

stress criterion, it is assumed that failure occurs when a stress parallel or normal to

the fibre axis reaches the appropriate critical value, that is when one of the following is

satisfied:

(22)

For any stress system (sx, sy and txy) applied to the ply, evaluation of

these stresses can be carried out as described in the section on

Composite Laminates (Eqs.(9) and (10)).

Figure 9

Monitoring of s1, s2 and t12 as the applied stress is increased allows

the onset of failure to be identified as the point when one of the

inequalities in Eq.(22) is satisfied. Noting the form of | T | (Eq.(10)),

and considering applied uniaxial tension, the magnitude of sx necessary

to cause failure can be plotted as a function of angle f between stress axis and fibre axis,

for each of the three failure modes.

(23)

(24)

(25)

The applied stress levels at which these conditions become satisfied

can be explored using page 5. As an example, the three curves

corresponding to Eqs.(23)-(25) are plotted in Fig. 9, using typical

values of s1*, s2* and t12*. Typically, axial failure is expected only for

very small loading angles, but the predicted transition from shear to

transverse failure may occur anywhere between 20° and 50°,

depending on the exact values of t12* and s2*.

In practice, there is likely to be some interaction between the failure

modes. For example, shear failure is expected to occur more easily if,

in addition to the shear stress, there is also a normal tensile stress

acting on the shear plane. The most commonly used model taking

account of this effect is the Tsai-Hill criterion. This can be expressed

mathematically as

(26)

This defines an envelope in stress space: if the stress state (s1, s2

and t12) lies outside of this envelope, i.e. if the sum of the terms on

the left hand side is equal to or greater than unity, then failure is

predicted. The failure mechanism is not specifically identified,

although inspection of the relative magnitudes of the terms in Eq.(26)

gives an indication of the likely contribution of the three modes. Under

uniaxial loading, the Tsai-Hill criterion tends to give rather similar

predictions to the Maximum Stress criterion for the strength as a

function of loading angle. The predicted values tend to be somewhat

lower with the Tsai-Hill criterion, particularly in the mixed mode

regimes where both normal and shear stresses are significant. This

can be explored on page 6.

What is the Failure Strength of a Laminate?

The strength of laminates can be predicted by an extension of the

above treatment, taking account of the stress distributions in

laminates, which were covered in the preceding section. Once these

stresses are known (in terms of the applied load), an appropriate

failure criterion can be applied and the onset and nature of the failure

predicted.

Figure 10

However, failure of an individual ply within a laminate does not

necessarily mean that the component is no longer usable, as other

plies may be capable of withstanding considerably greater loads

without catastrophic failure. Analysis of the behaviour beyond the

initial, fully elastic stage is complicated by uncertainties as to the

degree to which the damaged plies continue to bear some load.

Nevertheless, useful calculations can be made in this regime

(although the major interest may be in the avoidance of any damage

to the component).In page 7, a crossply (0/90) laminate is loaded in

tension along one of the fibre directions. The stresses acting in each

ply, relative to the fibre directions, are monitored as the applied stress

is increased. Only transverse or axial tensile failure is possible in

either ply, since no shear stresses act on the planes parallel to the

fibre directions. The software allows the onset of failure to be

predicted for any given composite with specified strength values.

Although the parallel ply takes most of the load, it is commonly the

transverse ply which fails first, since its strength is usually very low.

In page 8, any specified laminate can be subjected to an imposed

stress state and the onset of failure predicted. An example of such a

calculation is shown in Fig. 10.

What is the Toughness (Fracture Energy) of a Composite?

The fracture energy, Gc, of a material is the energy absorbed within it

when a crack advances through the section of a specimen by unit

area. Potentially the most significant source of fracture work for most

fibre composites is interfacial frictional sliding. Depending on the

interfacial roughness, contact pressure and sliding distance, this

process can absorb large quantities of energy. The case of most

interest is pull-out of fibres from their sockets in the matrix. This

process is illustrated schematically in page 9.

The work done as a crack opens up and fibres are pulled out of their

sockets can be calculated in the following way. A simple shear lag

approach is used. Provided the fibre aspect ratio, s (=L/r), is less than

the critical value, s* (=sf*/2ti*), see page 10 of the Load Transfer

section, all of the fibres intersected by the crack debond and are

subsequently pulled out of their sockets in the matrix (rather than

fracturing). Consider a fibre with a remaining embedded length of x

being pulled out an increment of distance dx. The associated work is

given by the product of the force acting on the fibre and the distance

it moves

dU = (2prxti*) dx(27)

 

where ti* is the interfacial shear stress, taken here as constant along the length of the

fibre. The work done in pulling this fibre out completely is therefore given by

(28)

where x0 is the embedded length of the fibre concerned on the side of

the crack where debonding occurs (x0 = L). The next step is an

integration over all of the fibres. If there are N fibres per m2, then

there will be (N dx0 / L) per m2 with an embedded length between x0

and (x0 + dx0). This allows an expression to be derived for the pull-out

work of fracture, Gc

(29)

The value of N is related to the fibre volume fraction, f, and the fibre

radius, r

N =

(30)

Eq.(29) therefore simplifies to

(31)

This contribution to the overall fracture energy can be large. For

example, taking f=0.5, s=50, r=10 µm and ti*=20 MPa gives a value of

about 80 kJ m-2. This is greater than the fracture energy of many

metals. Since sf* would typically be about 3 GPa, the critical aspect

ratio, s* (=sf*/2ti*), for this value of ti*, would be about 75. Since this is

greater than the actual aspect ratio, pull-out is expected to occur

(rather than fibre fracture), so the calculation should be valid. The

pull-out energy is greater when the fibres have a larger diameter,

assuming that the fibre aspect ratio is the same. In page 10, the

cumulative fracture energy is plotted as the crack opens up and fibres

are pulled out of their sockets. The end result for a particular case is

shown in Fig. 11.

Figure 11

CHAPTER-III

PRO-E & ANSYS

PRO-ENGINEER

Pro/ENGINEER, PTC's parametric, integrated 3D

CAD/CAM/CAE solution, is used by discrete manufacturers for

mechanical engineering, design and manufacturing. Created by Dr.

Samuel P. Geisberg in the mid-1980s, Pro/ENGINEER was the

industry's first successful parametric, 3D CAD modeling system. The

parametric modeling approach uses parameters, dimensions,

features, and relationships to capture intended product behavior and

create a recipe which enables design automation and the

optimization of design and product development processes. This

powerful and rich design approach is used by companies whose

product strategy is family-based or platform-driven, where a

prescriptive design strategy is critical to the success of the design

process by embedding engineering constraints and relationships to

quickly optimize the design, or where the resulting geometry may be

complex or based upon equations. Pro/ENGINEER provides a

complete set of design, analysis and manufacturing capabilities on

one, integral, scalable platform. These capabilities, include Solid

Modeling, Surfacing, Rendering, Data Interoperability, Routed

Systems Design, Simulation, Tolerance Analysis, and NC and

Tooling Design.

ANSYS

ANSYS is an engineering simulation software provider founded

by software engineer John Swanson. It develops general-purpose

finite element analysis and computational fluid dynamics software.

While ANSYS has developed a range of computer-aided engineering

(CAE) products, it is perhaps best known for its ANSYS Mechanical

and ANSYS Multiphysics products.

ANSYS Mechanical and ANSYS Multiphysics software are non

exportable analysis tools incorporating pre-processing (geometry

creation, meshing), solver and post-processing modules in a

graphical user interface. These are general-purpose finite element

modeling packages for numerically solving mechanical problems,

including static/dynamic structural analysis (both linear and non-

linear), heat transfer and fluid problems, as well as acoustic and

electro-magnetic problems.

ANSYS Mechanical technology incorporates both structural and

material non-linearities. ANSYS Multiphysics software includes

solvers for thermal, structural, CFD, electromagnetics, and acoustics

and can sometimes couple these separate physics together in order

to address multidisciplinary applications. ANSYS software can also

be used in civil engineering, electrical engineering, physics and

chemistry.

ANSYS, Inc. acquired the CFX computational fluid dynamics

code in 2003 and Fluent, Inc. in 2006. The CFD packages from

ANSYS are used for engineering simulations. In 2008, ANSYS

acquired Ansoft Corporation, a leading developer of high-

performance electronic design automation (EDA) software, and

added a suite of products designed to simulate high-performance

electronics designs found in mobile communication and Internet

devices, broadband networking components and systems, integrated

circuits, printed circuit boards, and electromechanical systems. The

acquisition allowed ANSYS to address the continuing convergence of

the mechanical and electrical worlds across a whole range of industry

sectors.

UNDERSTANDING THE NODES AND ELEMENTS

Red dots represent the element's nodes.

Elements can have straight or curved edges.

Each node has three unknowns, namely, the translations in the

three global directions.

The process of subdividing the part into small pieces (elements)

is called meshing. In general, smaller elements give more

accurate results but require more computer resources and time.

Ansys suggests a global element size and tolerance for

meshing. The size is only an average value, actual element

sizes may vary from one location to another depending on

geometry.

It is recommended to use the default settings of meshing for the

initial run. For a more accurate solution, use a smaller element

size.

LOADS & SUPPPORT APPLIED ON FLYWHEEL

CHAPTER-IV

MODELLING COMMANDS USED IN PRO-E

CREATE THE WORKING DIRECTORY-First create the working

directory to save the all model in one folder

File – set working directory – select the required folder – ok.

SKETCH- This command is used to create the new sketch like circle,

line, rectangle, ellipse, etc,..

The pro-e window select the sketch icon and select the plane or

surface want to sketch.

CIRCLE- This command is used to create the circle. Create circle by

picking the center point and a point on the circle from Right

Toolchest.

Pick the origin for the circle’s center - pick a point on the circle’s

edge- click the middle mouse button – ok

ELLIPSE- This command is used to create the ellipse. Create ellipse

by picking the center point and a minor radius point and major radius

point, the minor and major radius of the ellipse is vertical and

horizontal direction depend upon the shape of ellipse we want.

Select the ellipse icon from right toolchest- Pick the center for

the ellipse – pick the minor radius of ellipse point and pick the major

radius of the ellipse- click the middle mouse button – ok

LINE- This command is used to create the line. Create the line by

start point and end point.

Select the line icon from the right Toolchest – click the start point of

the line – click the end point of the circle -enter

ARC- This command is used to create the arc. Create the arc by

using three points. The three points are start point, end point and

center point of the arc.

Select the arc icon from the right Toolchest – click the start point of

the arc – click the end point of the arc and click the middle point of

the arc –enter.

The dimension of the arc is modified by double click on the arc

then the dimension will appear in the pop up box, then provide the

value of the arc.

CREATE THE HEXAGON – The hexagon is created by insert foreign

data icon in the Right Toolchest.

Insert foreign data from Palette into active object - scroll down to see

the hexagon - double-click hexagon- Place the hexagon on the

sketch by picking a position - with the left mouse button, drag and

drop the center of the hexagon at the origin - modify Scale value to

the required size – click enter

RECTANGLE- This command is used to create the rectangle and

square.

Click the rectangle icon in the right Toolchest – click the lower

left point of the rectangle and higher right corner of the rectangle we

want to draw.

After drawing the rectangle the dimension of the rectangle is

provided by the pick the dimension command from the dimension

icon in the right toolchest of the pro-e software.

DIMENSION- This command is used to provide the dimension of the

sketched entities the entities may be circle, line, rectangle, ellipse,

etc,..

The dimension is provide to the sketch by select the dimension

icon from the right tool chest then select the sketched entities and

press the middle mouse button to finish the dimensioning.

To change the dimension of the sketched entities by just double

click the dimension line of created sketch.

EXTRUDE – This command is used to create the material (to make

3D object from 2D sketch) from the sketched entities. The entities

may be circle, line or rectangle, etc,...

Select the extrude icon from the right toolchest then select the

sketched part in the window, enter the extrude length and press the

middle mouse button to finish the extrude command.

REVOLVE- This command is used to create the material from taking

the one axis and sketched entities. The axis is the center of the

revolved part. The revolve angle should between 0 degree to 360

degree.

Select the revolve icon from the right toolchest then select the

sketched part and axis of the object in the graphical window, enter

the revolve angle and press the middle mouse button to finish the

extrude command.

SWEEP FEATURES

The Sweep option extrudes a section along a defined trajectory.

The order of operation is to first create a trajectory and then a

section. A trajectory is a path along which a section is swept. The

trajectory for a sweep feature can be sketched or selected. The

Sweep option of protrusion is similar to the Extrude option. The only

difference is that in the case of the Extrude option, the feature is

extruded in a direction normal to the sketching plane, but in the case

of the Sweep option, the section is swept along the sketched or

selected trajectory. The trajectory can be open or closed. Normal

sketching tools are used for sketching the trajectory. The cross-

section of the swept feature remains constant throughout the sweep.

SWEEP CUT

To create a Sweep Cut feature, the procedure to be followed is

the same as that in Sweep Protrusion. The only difference is that in

case of cut features, the material is removed from an existing feature.

The Cut option can be invoked by choosing Insert > Sweep >

Cut from the menu bar. A cut can be a solid swept cut or a thin swept

cut.

CHAPTER-V

ANALYSIS PROCEDURE

FLEXIBLE DYNAMIC

Flexible dynamic analysis (also called time-history analysis) is a

technique used to determine the dynamic response of a structure

under the action of any general time-dependent loads. You can use

this type of analysis to determine the time-varying displacements,

strains, stresses, and forces in a structure as it responds to any

combination of static, transient, and harmonic loads. The time scale

of the loading is such that the inertia or damping effects are

considered to be important. If the inertia and damping effects are not

important, you might be able to use a static analysis instead.

ANALYZING THE FLYWHEEL – STEP BY STEP PROCEDURE

The 3D model of the flywheel is designed by using pro-e

software and it is converted as IGES format.

The IGES (International Graphic Exchange System) format is

suitable to import in the ANSYS Workbench for analyzing

Open the ANSYS workbench

Create new geometry

File – import external geometry file – generate

Project – new mesh

Defaults – physical preference – mechanical

Advanced – relevance center – fine

Advanced – element size – 100 mm

Right click the mesh in tree view – generate mesh

Project – convert to simulation – yes

Select the all solid in geometry tree

Definition – material – new material

New material – right click – rename – CAST IRON

Enter the value of the young’s modulus, poisons ratio, density

and etc,…

Define the another material – right click the materials – insert

new material – name it to EPOXY CARBON

Enter the value of the young’s modulus, poisons ratio, density

and etc,…

New analysis – flexible dynamic

Flexible dynamic – right click – insert – fixed support

Select the inner circular face of the flywheel

Geometry – apply

Flexible dynamic – right click - insert – rotational velocity –

select the face to define the velocity direction

Geometry – apply

Provide the value of the rotational velocity to 2600RPM

Flexible dynamic – right click - insert – moment – select the

face to define the moment direction and select the all surfaces

to the moment load

Provide the value of the moment 461N.m

Then define the solution

Solution – right click - insert the total deformation, equivalent

elastic strain, equivalent stress, shear elastic strain, shear

stress and total acceleration.

Right click the solution icon in the tree – solve

After solve the analysis – take the reading of above mentioned

items (i.e. total deformation, directional deformation, etc,…)

The all results are taken in a picture – and save it to the

required folder in the system

The material is changed to cast iron – in the previous steps –

the loads are to be same as the epoxy carbon

Solve again this analysis in the cast iron material

Now take again the six results – save the picture to the required

folder in the system

The all readings are tabulated

The results are compared to the two design of the flywheel

Finally we get the result which design withstands the load in

same load condition.

CHAPTER-VI

MATERIAL PROPERTIES

CAST IRON

Cast iron usually refers to grey iron, but also identifies a large

group of ferrous alloys, which solidify with a eutectic. The colour of a

fractured surface can be used to identify an alloy. White cast iron is

named after its white surface when fractured, due to its carbide

impurities which allow cracks to pass straight through. Grey cast iron

is named after its grey fractured surface, which occurs because the

graphitic flakes deflect a passing crack and initiate countless new

cracks as the material breaks.

Iron (Fe) accounts for more than 95% by weight (wt%) of the

alloy material, while the main alloying elements are carbon (C) and

silicon (Si). The amount of carbon in cast irons is 2.1 to 4 wt%. Cast

irons contain appreciable amounts of silicon, normally 1 to 3 wt%,

and consequently these alloys should be considered ternary Fe-C-Si

alloys. Despite this, the principles of cast iron solidification are

understood from the binary iron-carbon phase diagram, where the

eutectic point lies at 1,154 °C (2,109 °F) and 4.3 wt% carbon. Since

cast iron has nearly this composition, its melting temperature of 1,150

to 1,200 °C (2,102 to 2,192 °F) is about 300 °C (572 °F) lower than

the melting point of pure iron.

Cast iron tends to be brittle, except for malleable cast irons.

With its low melting point, good fluidity, castability, excellent

machinability, resistance to deformation, and wear resistance, cast

irons have become an engineering material with a wide range of

applications, including pipes, machine and automotive industry parts,

such as cylinder heads (declining usage), cylinder blocks, and

gearbox cases (declining usage). It is resistant to destruction and

weakening by oxidisation (rust).

DURALUMIN

Duralumin (also called duraluminum, duraluminium or dural) is

an alloy of aluminium (about 95%), copper (about 4%), and small

amounts of magnesium (0.5%–1%) and manganese (less than 1%). It

is far better in tensile strength than elemental aluminium, though less

resistant to corrosion. Its heat and electrical conductivity are less than

that of pure aluminium but much more than that of steel.

Duralumin was invented in 1908 by Alfred Wilm during research

for the German army. Its first use was rigid airship frames. Its

composition and heat-treatment were a wartime secret. With this new

rip-resistant mixture, duralumin quickly spread throughout the aircraft

industry in the early 1930s, where it was well suited to the new

monocoque construction techniques that were being introduced at the

same time. Duralumin also is popular for use in precision tools such

as levels because of its light weight and strength.

To prevent corrosion, alloy sheet can be covered with a thin

layer of pure aluminium. Alclad is a common trade name for this

material. Another unusually effective way of protecting the surface is

Anodising. Both methods can be used at once.

Its use in ground vehicle components has been limited by cost

of material and fabrication, relative to mild steel and cast iron, but it

has become fairly common, especially in cases where requirements

for acceleration, fuel efficiency, etc. demand light weight. Duralumin

components include wheels, cylinder heads, blocks, crank cases, oil

sumps, manifolds, bodies or body parts (Land Rover, Honda Insight,

Lotus Seven, Austin-Healey), frames (M2 Bradley fighting vehicle, a

very high performance Chevrolet Corvette version, Messerschmitt

KR200), bumpers and fuel tank (Panhard), differential case

(Peugeot), bonnet (hood) and boot cover (trunk lid) (MG A).

Today almost all material that claims to be aluminium is actually

an alloy thereof. Pure aluminium is encountered only when corrosion

resistance is more important than strength or hardness. Copper-free

aluminium is specified for such uses. Conversely, the term "alloy"

usually means aluminium alloy. In modern aircraft Duralumin has

evolved into the alloys known as 2017 2117 and 2024.

HIGH STRENGTH EPOXY CARBON

This material is known for its high specific stiffness and

strength, given by epoxy carbon. The material has an advantageous

combination of good mechanical properties and low weight.

The properties of the material vary depending on the content

and orientation of the fibres.

It is used for very stiff and light structures within sport

equipment, aerospace, medical equipment (protheses) and

prototyping.

Epoxy is a strong and very resistant thermoset plastic. It is used

as an adhesive agent, as filling material, for moulding dies, and as a

protective coating on steel and concrete. Many composite materials

are reinforced epoxy.

Epoxy is resistant to almost all acids and solvents, but not to

strong bases or solvents with chlorine content.

By adding a hardening agent curing takes place. The type of

hardener has a major influence on properties and applications of

epoxies.

CHAPTER-VII

RESULTS

DESIGN OF CAST IRON

Total Deformation

Equivalent Elastic Strain

Equivalent Stress

DESIGN OF DURALUMIN

Total Deformation

Equivalent Elastic Strain

Equivalent Stress

DESIGN OF EPOXY CARBON

Total Deformation

Equivalent Elastic Strain

Equivalent Stress

RESULT COMPARISION FOR CAST IRON

CAST IRON OLD DESIGN MODIFIED

Total deformation (mm) 1.9466e-002 1.4553e-002

Equivalent elastic strain 3.0523e-004 3.1043e-004

Equivalent stress (N/mm2) 33.576 34.147

RESULT COMPARISION OF DURALUMIN

DURALUMIN OLD DESIGN MODIFIED

Total deformation (mm) 1.5307e-008 1.1208e-008

Equivalent elastic strain 2.3114e-010 2.147e-010

Equivalent stress (N/mm2) 18.491 17.176

RESULT COMPARISION OF EPOXY CARBON

EPOXY CARBON OLD DESIGN MODIFIED

Total deformation (mm) 0.13184 9.585e-002

Equivalent elastic strain 1.9536e-003 1.6809e-003

Equivalent stress (N/mm2) 1.9536e-003 18.551

CHAPTER-VIII

CONCLUSION

The analysis of flywheel we found that the duralumin material

have a good physical properties and it have a less deformation under

the moment and velocity, then the epoxy carbon material have just

more deformation compared to the duralumin and finally the

deformation, stress, strain of the duralumin is low compared to the

three materials. From the analysis the shear stress produced by the

epoxy carbon is less compared to the cast iron and the shear stress

produced by the epoxy carbon is just high compared to the

duralumin. So the material chosen to manufacturing the flywheel is

duralumin and epoxy carbon to replacing the present material of the

cast iron.

The project carried out by us will make an impressing mark in

the field of automobile. This project we are design and analyze the

flywheel used in an IC engine.

Doing this project we are study about the 3Dmodelling software

(PRO-E) and Study about the analyzing software (ansys) to develop

our basic knowledge to know about the industrial design.

REFERENCE

1. Machine design, R S Khurmi, 2003 edition, Pg No’s:701-741

2. Theory and Design of Automotive Engines - B Dinesh Prabhu,

Assistant Professor, P E S College of Engineering, Mandya,

Karnataka

3. Design Data Book – PSG Tech

4. http://www.carfolio.com/ - For Ambassador Car specifications

5. COMPOSITE MATERIALS DESIGN AND APPLICATIONS, Daniel

Gay, Suong V. Hoa, Stephen W. Tsai.