Design and Prototyping of Piston

8/15/2019 Design and Prototyping of Piston

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MODELLING AND ANAYLSIS OF I.C. ENGINE

PISTON CROWN USING FEM PACKAGE ANSYS

ABSTRACT

A piston is a component of reciprocating engines, pumps and gas

compressors. It is located in a cylinder and is made gas-tight by piston rings. In an

engine, its purpose is to transfer force from expanding gas in the cylinder to the

crankshaft via a piston rod and/or connecting rod. The alloy from which a piston is

made not only determines its strength and wears characteristics, but also its thermal

expansion characteristics. otter engines re!uire more stable alloys to maintain close

tolerances without scuffing.

The normal temperature of gasoline engine exhaust is approximately "#$%&

'()*%+. This is also approximately the melting point of most aluminum alloys and it

is only the constant influx of ambient air that prevents the piston from deforming and

failing. or this purpose testing different types of materials such as aluminum alloys

and cast iron piston.

In this proect we design the three models of pistons flat head, concave head

convex heads by using 0ro-1ngineer #.$ software, and imported them to make

analysis in A2343 55.$ software. And find out the vonmisses stresses, total

deformation, heat distribution, and heat flux. 6y comparing the results we can say

among these which one of the piston had better results.

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LIST OF FIGURES

Figure No Name of the figure Page No

5 Ideal indicator diagram of )-stroke 3I engine )

) Ideal 07 diagram of 8-stroke 3I engine *

* 0arts of an I& engine 8

8 &onduction in metal rod "

# 0iston samples 9

" &ompression ratio 5)

: 0iston rings 58

9 ;ifferent types of crowns used for piston 5(

( 0roportions of piston )8

5$ 3ketch of piston in pro-engineer **

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)* Total ;eformation in the &onvex 3haped ##

&rown 0iston

)8 1!uivalent strain enerated in the &onvex ##

3haped &rown 0iston

)# 1!uivalent 3tress enerated In the &onvex #"

3haped &rown 0iston

)" Total ;eformation In The lat 3haped &rown #:

0iston

): 1!uivalent strain enerated in the lat 3haped #:

&rown 0iston

)9 1!uivalent 3tress enerated In the lat 3haped #9

&rown 0iston

)( Temperature ;istribution for &oncave 3haped "$

&rown 0iston

*$ 1!uivalent strain enerated in the &oncave "$

3haped &rown 0iston

*5 Temperature ;istribution for &onvex 3haped "5

&rown ead

*) 1!uivalent strain enerated in the &onvex ")

3haped &rown 0iston

** Temperature ;istribution for lat 3haped "*

&rown 0iston

*8 1!uivalent strain enerated in the lat 3haped "*

&rown 0iston

*# igure 3hows the 6oundary &onditions Applied ":or 0iston

*" igure 3hows 3tructural ?oad Acting @n The ":

0iston ead

*: Total ;eformation for &oncave 3haped &rown "9

0iston

*9 1!uivalent strain enerated in the &oncave "9

3haped &rown 0iston

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*( 1!uivalent 3tress enerated In The &oncave "(

3haped &rown 0iston

8$ Total ;eformation In The &onvex 3haped :$

&rown 0iston

85 1!uivalent strain enerated in the &onvex :$

3haped &rown 0iston

8) 1!uivalent 3tress enerated In the &onvex :5

3haped &rown 0iston

8* Total ;eformation In The lat 3haped &rown :)

0iston

88 1!uivalent strain enerated in the lat 3haped :)

&rown 0iston

8# 1!uivalent 3tress enerated In the lat 3haped :*

&rown 0iston

8" Temperature ;istribution for &oncave 3haped :#

&rown 0iston

8: 1!uivalent strain enerated in the &oncave :#

3haped &rown 0iston

89 Temperature ;istribution for &onvex 3haped :"

&rown ead

8( 1!uivalent strain enerated in the &onvex ::

3haped &rown 0iston

#$ Temperature ;istribution for lat 3haped :9

&rown 0iston

#5 1!uivalent strain enerated in the lat 3haped :9

&rown 0iston

LIST OF TABLES

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S.No Name of the ta!e Page No

5 The usual proportions of piston and piston rings )8

) 6ore diameters for I& engines )#

* Typical yield strength *$8 0roperties of ray cast iron *$

# Applications areas of inite element methods *:

" Aluminum alloy B constants #5

: 3tatic structural B loads #5

9 Aluminum alloy B constants #(

( 3teady-state thermal B loads #(

5$ inal results of different crowns of aluminum alloy "#

55 &ast iron B constants ""

5) 3tatic structural B loads ""

5* &ast iron B constants :8

58 3teady-state thermal B loads :8

5# inal results of different crowns of cast iron :(

LIST OF GRAP"S

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S.No Name of the graph Page No

5 raph of concave shaped piston crown having total #8

;eformation, stress, strains 7s loads

) raph of convex shaped piston crown having total #";eformation, stress, strains 7s loads

* raph of flat shaped piston crown having total #9;eformation, stress, strains 7s loads

8 raph of concave shaped piston crown having "5>aximum temperature, minimum temperature 7sApplied ?oads

# raph of convex shaped piston crown having >aximum ")Temperature, minimum temperature 7s Applied loads

" raph of flat shaped piston crown having >aximum "8Temperature, minimum temperature 7s Applied loads

: raph of concave shaped piston crown having total "(


9 raph of convex shaped piston crown having total :5


( raph of flat shaped piston crown having total :*;eformation, stress, strains 7s loads

5$ raph of concave shaped piston crown having >aximum :"Temperature, minimum temperature 7s Applied loads

55 raph of convex shaped piston crown having >aximum ::Temperature, minimum temperature 7s Applied loads

5) raph of flat shaped piston crown having >aximum :(Temperature, minimum temperature 7s Applied loads

INTRO#UCTION TO "EAT ENGINES$

5.5 eat 1ngines

Any type of engine or machine which derives heat energy from the

combustion of fuel or any other source and coverts this energy into mechanical work

is termed as a heat engine.

eat engines may be classified asC

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5 1xternal &ombustion 1ngines

) Internal &ombustion 1ngines

5.5.5 1xternal &ombustion 1ngines '1.&. 1ngines

In this case, combustion of fuel takes place outside of the cylinder as in case of steam engines where the heat of combustion is employed to generate steam which is

used to move a piston in a cylinder.

5.5.) Internal &ombustion 1ngines 'I.&. 1ngines

In this case, combustion of the fuel with oxygen of the air occurs within the

cylinder of the engine. The internal combustion engines group includes engines

employing mixtures of combustible gases and air, known as gas engines, those using

lighter li!uid fuel or spirit known as petrol engines and those using heavier li!uidfuels, known as oil compression or diesel engines.

1ven though internal combustion engines look !uite simple, they are

highly complex machines. There are hundreds of components which have to perform

their functions satisfactorily to produce output power. There are two types of engines

5. 3park ignition engine '3.I engine

). &ompression ignition engine '&.I engine

According to the cycle of operations again these engines are classified as

o Two-stroke engines

o our-stroke engines

5.).A Two-stroke 3.I engineC-

;ugald &lark invented the two stroke engine in the year 59:9.The two strokes

are literally DsuctionE and DexhaustE. In two stroke engine the cycle is completed inone revolution of the crank shaft.

The main difference between two stroke and four stroke engines is in the

method of filling the fresh charge and removing the burnt gases from the cylinder. In

the four stroke engines these operations are performed by the engine piston during the

suction and exhaust strokes respectively. In a two stroke engine, the filling process is

accomplished by the charge compressed in the crankcase or by a blower. The

induction of the compressed charge moves out the product of combustion through

exhaust ports. Therefore no piston strokes are re!uired for these two operations. Two

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strokes are sufficient to complete the cycle, one for compressing the fresh charge and

the other for expansion or power stroke.

Fig %$ I&ea! In&i'ator #iagram of T(o)Stro*e SI Engine

5.*.A our stroke 3.I engineC-

In a four stroke engine, the cycle of operations are completed in four strokes of the

piston or two revolutions of the crankshaft. ;uring the four strokes, there are five

events to be completed, viF., suction compression, combustion, expansion, and

exhaust. 1ach stroke consists of 59$ $ of crankshaft rotation and hence a four stroke

cycle is completed through :)$ $ of crank rotation. The cycle of operation for an ideal

four stroke engine consists of the following strokes. 'i 3uction or intake strokeG 'ii

&ompression strokeG 'iii 1xpansion or power stroke 'iv 1xhaust stroke

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Fig +$ I&ea! P), #iagram of a Four -Stro*e SI Engine

5.8 ;ifferent parts of an I.&. engines

ere follows the detail of the various parts of an internal combustion engine.

A cross-section of an air-cooled I.&. engine with principal parts is shown in figure 5.

0arts of an I.&. 1ngineC

5. &ylinder

). &ylinder head

*. 0iston

8. udgeon pin

#. &onnecting rod

". &rankshaft

:. &rank

9. &rank case

(. lywheel

5$. overnor

55. 7alves and valve operating mechanism

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Fig $ Parts of an I.C Engine

5.# =orking cycles

An internal combustion engine can work on any one of the following cyclesCA &onstant volume or @tto cycle

6 &onstant pressure or ;iesel cycle

& ;ual combustion cycle

5." eat Transfer In The &ylinder To The ;ifferent 0arts @f 1ngine

5.".5 &onduction

&onduction is the transfer of heat by direct contact of particles of matter. The transfer

of energy could be primarily by elastic impact as in fluids or by free electron diffusionas predominant in metals or photon vibration as predominant in insulators. In other

words, heat is transferred by conduction when adacent atoms vibrate against one

another, or as electrons move from atom to atom.

&onduction is greater in solids, where atoms are in constant contact. In li!uids

'except li!uid metals and gases, the molecules are usually further apart, giving a

lower chance of molecules colliding and passing on thermal energy. eat conduction

is directly analogous to diffusion of particles into a fluid, in the situation where there

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are no fluid currents. This type of heat diffusion differs from mass diffusion in

behavior, only in as much as it can occur in solids, whereas mass diffusion is mostly

limited to fluids. >etals 'e.g. copper, platinum, gold, iron, etc. are usually the best

conductors of thermal energy. This is due to the way that metals are chemically

bonded, have free-moving electrons which are able to transfer of thermal energy

rapidly through the metal.

As density decreases so does conduction. Therefore, fluids 'and especially

gases are less conductive. This is due to the large distance between atoms in a gas,

fewer collisions between atoms means less conduction. &onductivity of gases

increases with temperature. &onductivity increases with increasing pressure from

vacuum up to a critical point that the density of the gas is such that that molecules of the gas may be expected to collide with each other before they transfer heat from one

surface to another. After this point in density, conductivity increases only slightly with

increasing pressure and density.

To !uantify the ease with which a particular medium conducts, employ the

thermal conductivity, also known as the conductivity constant or conduction

coefficient, k. In thermal conductivity k is defined as the !uantity of heat, H,

transmitted in time 't through a thickness '?, in a direction normal to a surface of

area 'A, due to a temperature difference 'T. Thermal conductivity is a material

property that is primarily dependent on the mediumJs phase, temperature, density, and

molecular bonding.

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Fig /$ Con&u'tion in meta! ro&

5.".) &onvection

&onvection is transfer of heat by movement of a heated fluid. Knlike the case

of pure conduction, now currents in fluids are additionally involved in convection.

This movement occurs into a fluid or within a fluid, and cannot happen in solids. In

solids, molecules keep their relative position to such an extent that bulk movement or

flow is prohibited, and therefore convection does not occur.

In natural convection 'known as free convection a fluid surrounding a heat

source receives heat, becomes less dense and rises. The surrounding, cooler fluid then

moves to replace it. This cooler fluid is then heated and the process continues,forming convection current. The driving force for natural convection is buoyancy, a

result of differences in fluid density when gravity or any type of acceleration is

present in the system.

orced convection, by contrast, occurs when pumps, fans or other means are

used to propel the fluid and create an artificially induced convection current. orced

heat convection is sometimes referred to as heat advection. To calculate the rate of

convection between an obect and the surrounding fluids, employ the heat transfer

coefficient, h. Knlike the thermal conductivity, the heat transfer coefficient is not a

material property. The heat transfer coefficient depends upon the geometry, fluid,

temperature, velocity, and other characteristics of the system in which convection

occurs.

It should be noted that convection does not occur in a perfect vacuum due to

the lack of media to transmit heat. This mode of heat transfer does not occur in spacewhere there is no atmosphere in the surroundings of the system to be analyFed. It only

occurs where gases are present.

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warming the earth. Also, the only way that energy can leave earth is by being radiated

to space.

6oth reflectivity and 1missivity of all bodies is wavelength dependent. The

temperature determines the wavelength distribution of the electromagnetic radiation

as limited in intensity by 0lanckLs law of black-body radiation. or any body the

reflectivity depends on the wavelength distribution of incoming electromagnetic

radiation and therefore the temperature of the source of the radiation. The 1missivity

depends on the wave length distribution and therefore the temperature of the body

itself.

LITERATURE RE,IE0$

C". ,EN1ATA RA2A34P. ,. 1. 3URT"5 63. ,. S. 3URALI 1RIS"NA

An optimiFed piston which is lighter and stronger is coated with Firconium for

bio-fuel. The low grade ?< engines are using ceramic coatings on piston, liner and

cylinder head, while medium grade ?< engines provide air gap in the piston and

other components. It is necessary to test the coated piston for withstanding the stresses

and strains. In this paper, the coated piston undergone a vonmisses test by using

A2343 for load applied on the top. Analysis of the stress distribution was done onvarious parts of the coated piston for finding the stresses due to the gas pressure and

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thermal variations. 7onmisses stress is increased by 5"M and deflection is increased

after optimiFation. 6ut all the parameters are well with in design consideration.

S"UOGUO 7"AO

The piston is a NheartN of the engine and its working condition is the worst

one of the key parts of the engine in the working environment. 3o it is very important

for structural analysis of the piston. This paper analyses and calculates the piston by

0roO1211< software to gain a result, which improves and optimiFes the structure of

the piston.

S0ATI S C"OUGULE4 ,INA5A1 " 1"ATA0ATE

This work describes the stress distribution of the piston by using

finite element method '1>. 1> is performed by using computer aided

engineering '&A1 software. The main obective of this proect is to investigate and

analyFe the stress distribution of piston at the actual engine condition during

combustion process. The parameter used for the simulation is operating gas pressure

and material properties of piston. The report describes the mesh optimiFation by using

1> techni!ue to predict the higher stress and critical region on the component. The

piston under study belongs to the two stroke single cylinder engine of 3KPK+I

>ax5$$ motorcycle. Aluminum is selected as piston material. It is important to locate

the critical area of concentrated stress for appropriate modification. &omputer aided

design '&A; software 0


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automotive pistons is aluminum due to its light weight, low cost, and acceptable

strength. The alloying element of concern in automotive pistons is silicon. owever,

when silicon is added to aluminum they only blend together evenly on a molecular

level up to approximately a 5)M silicon content. 3ilicon in this context can be thought

of as Dpowdered sandE. Any silicon that is added to aluminum above a 5)M content

will retain a distinct granular form instead of melting. 3pecial moulds, casting, and

cooling techni!ues are re!uired to obtain uniformly dispersed silicon particles

throughout the piston material.

The alloy from which a piston is made not only determines its strength and

wears characteristics, but also its thermal expansion characteristics. otter engines

re!uire more stable alloys to maintain close tolerances without scuffing. 3iliconimproves high heat strength and reduces the coefficient of expansion so tighter

tolerances can be held as temperatures change.

ypereutectic alloys are also slightly lighter than standard alloys. 6ut the

castings are often made thinner because the alloy is stronger, resulting in a net

reduction of up to 5$ percent in the pistons total weight. ypereutectic alloys are

more difficult to cast because the silicon must be kept evenly dispersed throughout the

aluminum as the metal cools. 0article siFe must also be carefully controlled so the

piston does not become brittle or develop hard spots making it difficult to machine.

3ome pistons also receive a special heat treatment to further modify and improve the

grain structure for added strength and durability.

5.:.)The reason for their development

>ost automotive engines use aluminum pistons that move in an iron cylinder.

The average temperature of a piston crown in a gasoline engine during normal

operation is typically about *$$%& '#:*%+ and the coolant that runs through the

engine block is usually regulated at approximately ($%& '*"*%+. Aluminum expands

more than iron at this temperature range so for the piston to fit the cylinder properly

when at a normal operating temperature, the piston must have a loose fit when cold. It

was discovered that when an engine was cold during start-up, a small amount of fuel became trapped between the piston rings. As the engine warmed up, the piston

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expanded and expelled this small amount of fuel which added to the amount of

unborn hydrocarbons in the exhaust.

6y adding silicon to the pistonJs alloy, the piston expansion was dramatically

reduced. This allowed specifying a much tighter cold-fit between the piston and the

cylinder liner. 3ilicon itself expands less than aluminum but it also acts as an insulator

to prevent the aluminum from absorbing as much of the operational heat as it

otherwise would. Another benefit of adding silicon is that the piston becomes harder

and is less susceptible to scuffing which can occur when a soft aluminum piston in a

relatively dry cylinder on start-up or during abnormally high operating temperatures.

The biggest drawback of adding silicon to pistons is that the piston becomes more

brittle as the ratio of silicon is added. This makes the piston more susceptible tocracking if the engine experiences pre-ignition or detonation.

5.:.* 0erformance of replacement alloys

=hen auto enthusiasts want to increase the power of the engine they may add some

type of forced induction. 6y compressing more air and fuel into each intake cycle, the

power of the engine can be dramatically increased. This also increases the heat and

pressure in the cylinder. The normal temperature of gasoline engine exhaust isapproximately "#$%& '()*%+. This is also approximately the melting point of most

aluminum alloys and it is only the constant influx of ambient air that prevents the

piston from deforming and failing.

orced induction increases the operating temperatures while Dunder boostE

and if the excess heat is added faster than engine can shed it, the elevated cylinder

temperatures will cause the air and fuel mix to auto-ignite on the compression stroke

before the spark event. This is one type of engine *no'*ing that causes a sudden

shockwave and pressure spike, which can result in an immediate and catastrophic

failure of the piston and connecting rod.

5.:.8 orged versus &ast

or applications which re!uire stronger pistons, a forging process is used. In

the forging process the rough casting is placed in a die set while it is still hot and

semi-solid. A hydraulic press is used to place the rough slug under tremendous pressure. This removes any possible porosity and also pushes the alloy grains together

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tighter than can be achieved by simple casting alone. The result is a much stronger

material.

ypereutectic pistons can be forged but typically are only cast because the

extra expense of forging is not ustified when cast pistons are considered strong

enough for stock applications.

5.:.# 0arts of a piston

5 0iston head or &rown

) 0iston rings

* 0iston barrel

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;isplacement Q A x 3 x 2

=here A Q area of the piston 'in s!uare inches

3 Q stroke 'in inches

2 Q number of cylinders

5.:.".# &ompression ratioC the extent to which the combustible gasses are

compressed within the cylinder. It e!uals the volume existing within the cylinder with

the piston at bottom dead center divided by the volume within the cylinder when the

piston is at top dead center.

&ompression


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It is a good indicator of the class and performance of an engine relative to its

competitors.

There are some features of close tolerance piston mentioned belowC

5. 0iston can swell and stick.

). its tightly in the cylinder.

*. Tight Tolerance fit.

8. 0roperties alter due to atmospheric change.

#. 6acklash may such, some of the bin material into the valve which also can

cause the piston to stick.

5.:.: 0iston ring

0iston ring is an open-ended ring that fits into a groove on the outer diameter of a

piston in a reciprocating engine such as an internal combustion engine or steam

engine. The three main functions of piston rings in reciprocating engines areC

5. 3ealing the combustion/expansion chamber.

). 3upporting heat transfer from the piston to the cylinder wall.

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Fig :$ Piston rings

5.:.9 =ear due to piston side-load

Top ring and oil control rings will be coated with &hromium or 2itride- possibly plasma sprayed or has a 07; 'physical vapour deposit ceramic coating. or

enhanced scuff resistance and further improved wear, most modern diesel engines

have top rings coated with a modified chromium coating known as &+3. The lower

oil control ring is designed to leave a lubricating oil film, a few micrometers thick on

the bore, as the piston descends. Three piece oil rings, i.e. with two rails and one

spacer, are used for four-stroke gasoline engines

5.:.( ;rawbacks of a 0iston

3ince itLs a main reciprocating part of an engine and hence it creates the

problems of unbalancing due to its inertia. ;ue to friction between wall of the

cylinder and piston rings its life becomes short and it generates the unpleasant sound

due reciprocating mechanism. To transmit the energy of reciprocating piston, it is

connected to a connecting rod and crank mechanism and due to these parts there

occurs mechanical loss. The motion of the crank shaft is not smooth, since energy

supplied by the piston is not continuous and it is impulsive in nature.

;etonation causes three types of failureC

5. >echanical damage 'broken ring lands

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). Abrasion 'pitting of the piston crown

*. @verheating 'scuffed piston skirts due to excess heat input or high coolant

temperatures

The high impact nature of the spike can cause fracturesG it can break the spark

plug electrodes, the porcelain around the plug, cause a clean fracture of the ring land

and can actually cause fracture of valves-intake or exhaust. The piston ring land,

either top or second depending on the piston design, is susceptible to fracture type

failures.

=hen the piston crown temperature rises rapidly it never has time to get to the

skirt and expand and cause it to scuff. It ust melts the center right out of the piston.

ThatJs the biggest difference between detonation and pre-ignition when looking at

piston failures. =ithout a high pressure spike to resonate the chamber and block, we

could never hear pre-ignition. The only sign of pre-ignition is white smoke pouring

out the tailpipe and the engine !uits running.

There are no engines that will live for any period of time when pre-ignition

occurs. =hen people see broken ring lands they mistakenly blame it on pre-ignitionand overlook the hammering from detonation that caused the problem. A hole in the

middle of the piston, particularly a melted hole in the middle of a piston, is due to the

extreme heat and pressure of pre-ignition.

Another thing detonation can cause is a sandblasted appearance to the top of the

piston. The piston near the perimeter will typically have that kind of look if

detonation occurs. The detonation, the mechanical pounding, actually mechanically

erodes or fatigues material out of the piston. =e can typically expect to see that

sanded look in the part of the chamber most distant from the spark plug, The typical

pre-ignition indicator, of course, would be the hole in the piston. This occurs because

in trying to compress the already burned mixture the parts soak up a tremendous

amount of heat very !uickly.

The only ones that survive are the ones that have a high thermal inertia, like the

cylinder head or cylinder wall. The piston, being aluminum, has a low thermal inertia

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'aluminum soaks up the heat very rapidly. The crown of the piston is relatively thin,

it gets very hot, it canJt reect the heat, it has tremendous pressure loads against it and

the result is a hole in the middle of the piston where it is weakest.


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6y retaining minimal heat on the surface of the piston, less heat is transferred

to the incoming fuel mixture, leading to a reduction in pre-ignition which leads to

detonation. The coatings can also allow heat at the surface to move more evenly over

the surface reducing hot spots and the coatings reflect heat into the chamber for more

even distribution of heat, allowing more efficient combustion of the fuel. This allows

more of the fuel molecules to be oxidiFed, which in turn, means less fuel is needed for

optimum power. The result is an engine that makes more power, can be run with a

leaner air/fuel mix and less initial timing and has less thermal expansion due to a

reduction in the heat absorbed.

6y applying a ;ry ilm ?ubricant, friction, galling and wear is reduced. The

lubricants are capable of carrying loads beyond the crush point of the piston. Inaddition, the lubricants are Nfluid retainingN materials that actually hold oil to the

surface beyond the pressure where the oil would normally be s!ueeFed off. The ability

to carry greater loads, up to *#$,$$$ 03I, while increasing lubricity 'reduced friction

allows tighter piston to wall clearances to be run. This leads to better sealing with no

increase in friction.

6y applying Tech ?ineJs T?T; to the underside of the piston, oil that is

splashed onto the piston to cool it will shed rapidly. eat transfers most rapidly when

there is a large difference in temperature. The longer oil clings to a hot surface the

hotter the oil becomes. 6y shedding the cooling oil more rapidly, cooler oil is

splashed over the surface more fre!uently. If the oil NhangsN longer, it absorbs less

heat and blocks cooler oil from contacting the hot surface. A cooler piston grows less,

allowing tighter piston to wall clearances.

The thermal barrier crown coating is applied to the top of the piston and isdesigned to reflect heat into the combustion chamber, thereby increasing exhaust gas

velocity and greatly improving scavenging potential. The $.$$5#N thick coating can

also assist in extending piston life by decreasing the rate of thermal transfer.

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5 3kirt &oating '3&

This is coating applied to the skirt of the piston only, designed to show wear.

This coating is a $.$$$*E to $.$$$#E thick spray-on dry film that will help reduce

friction. 2o manufacturing allowance is re!uired as this application is made to wear in

to the cylinder wall.

) Thermal 6arrier &rown '&&

The thermal barrier crown coating is applied to the top of the piston and is

designed to reflect heat into the combustion chamber, thereby increasing exhaust gas

velocity and greatly improving scavenging potential. The $.$$5#E thick coating canalso assist in extending piston life by decreasing the rate of thermal transfer.

* +ool+ote '++

+ool+ote is an aerospace !uality hard anodiFe applied to all surfaces of the

piston with a buildup of $.$$5E. It will withstand greater temperatures and will not

flake, chip or peel. This coating does alter the heat transfer and expansion

characteristics of the piston.

8 Tuff 3kirt 'T3

Tuff 3kirt is a lubricating, anti-friction / anti-wear coating applied to the piston

skirt only. Knlike standard 3kirt &oating, Tuff 3kirt will not wear and is designed to

withstand many different types of endurance applications, is $.$$$#E per surface and

finished diameter of skirt should include the coating buildup.

# @il 3hed &oating '@3

This coating is applied to the underside of the piston. It is intended to reduce

the reciprocating weight by repelling oil !uicker than an untreated part. 2o additional

manufacturing is re!uired.

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" Top roove ard AnodiFe '&

This coating has proven to increase power output by allowing for extremely

tight ring clearances. Available exclusively to top-level racing teams until now, this

top ring groove coating creates a hard mating surface which virtually eliminates

micro-welding while decreasing ring groove wear. 6uildup is $.$$$)#E per surface

and clearance must be added during manufacturing to accommodate the change.

%;

S*irt Coating +; Therma! Barrier Cro(n ; 1oo!1ote

8 Tuff S*irt 8; Oi! She& Coating 9; Top Groo


28/93

The piston head is assumed to be a flat disc or uniform thickness fixed at the

edges and subected to a uniformly distributed gas load. Also the piston head has to with

stand high thermal stresses. ence the piston head is designed based on its strength to

with stand gas load and also the dissipation of heat produced during the combustion

process.

6ased on strength consideration, the thickness of piston head is given byC

t QU V'*0in ;W / '5" 3tpX

=here

0in Q >aximum gas pressure, in '2/mmW

; Q ;iameter of piston or &ylinder bore, in 'mm

3tp Q Allowable tensile stress of piston material,

Q *# to 8$ 2/mmW for &ast Iron,

Q #$ to ($ 2/mmW for Aluminum.

6ased on eat dissipation the head thickness is determined asC

t Q V'5$$$ / '5).#"+ 'Tc-TeX

=here Q eat flowing through the head '+= Q & S m S &v S 0s

& Q &onstant 'usually $.$#

m @ mass of the fuel used 'i.e. fuel consumption, in '+g/+=/3

&v @ igher &alorific value of the uel

Q 88 x 5$Y +Z/+g for ;iesel

Q 55x5$Y +Z/+g for 0etrol

0 b Q 6rake power of the 1ngine per cylinder '+= Q V'0?An / '"$x5$"X +=

0 Q 6rake mean effective pressure, in '2 [ mmW

? Q 3troke length, in 'mm

A Q Area of the piston at its top side, in 'mmW

n Q 2umber of power strokes per minutek Q eat conductivity factor '+=/m/\&

Q 8"."x5$]Y for &ast Iron

Q 5:#x5$]Y for Aluminum alloys

Tc Q Temperature at the centre of piston head '\&

Te Q Temperature at the edge of piston head '\&

Q :#\& for Aluminum alloys

).)


29/93

To make the piston rigid and to prevent distortion due to gas load and

connecting rod thrust form to six ribs are provided at the inner side of the piston.

The thickness of rib is assumed asC

t) Q '$.* to $.# S t5

=here t5 is thickness of piston head.

).* 0iston


30/93

).8 0iston barrelC

The cylindrical portion of the piston is termed as piston barrel. The barrel

thickness may be varied from the top side to bottom side of the piston. The maximum

thickness of barrel nearer to piston head is given byt# Q $.$*; ^ b ^ 8.# mm

=here b Q


31/93

The pin should be made of case hardened alloy steel containing nickel,

chromium, molybdenum etc with an ultimate strength of :$$ to ($$2/mmW in order to

with stand high gas pressure. The piston pin is designed based on the bearing pressure

consideration.

?et ?Qlength of piston pin

; Q diameter of piston pin

0n Q Allowable bearing pressure of piston Q5#to*$2/mmW

6eing strength of piston pin

b Q bearing pressure S proected area Q 0 bS S d

6y e!uating this being pressure to gas force

0 S S d Qg

=here g Q '`/8 S ;W S 0m

Ksually /d Q5.# to )

The piston is checked for bending, as the induced 6ending stress,

3 b Q V'*) >/ `dYX 3 b

=here > Q bending moment Q 'g S ;/9

; Q bore diameter

g Qgas force

3 b Q allowable bending stress

Q 98 2/mmW for case hardened steel

Q 8$ 2/mmW for heat treated alloy steel

The gudgeon pin is fitted at a distance of ?s/) from open end when ?s is the skirt

length

*5


32/93

Fig $ Proportions of piston

Ta!e no$ % The usua! proportions of piston an& piston rings$

#es'ription Petro! engine #iese! engine

&rown thickness, t5 '$.$$# B $.5$ ; '$.5) B $.)$ ;0iston height, ? p '$.9 B 5.* ; '5.$ B 5.: ;eight of top part, ?n '$.8# B $.:# ; '$." - 5.$ ;3kirt height, ?s '$." B $.9 ; '$." B 5.5 ;Thickness of skirt wall,t" 5.# B 8.# mm ).$ -#.$ mmThickness of crown wall,t# '$.$# B $.5 ; '$.$# -$.5 ;Thickness of ring land, R '$.$* -$.$# ; '$.$8 B $.$: ;;istance of first ring, R '$.$" B $.5) ; '$.55 B $.)$ ;


33/93

@il hole diameter, do '$.* B $.# t8 '$.* B $.# t80in outer diameter, d p '$.)) B $.)9 ; '$.* B $.# ;0in inner diameter, di '$."# B $.:# d p '$.# B $.: d p0in length, ? p

for retained pin for floating pin

'$.99 B $.(* ;'$.:9 B $.99 ;

'$.99 B $.(* ;'$.9 B $.( ;

&onnecting rod bushing length,

?c

for retained pin

for floating pin

'$.)9 B $.*) ;

'$.** B $.8# ;

'$.)9 B $.*) ;

'$.** B $.8# ;

Ta!e. No$ + Bore &iameters for I.C. Engines

*$, *), *8,*", *9, 8$, 88, 8", 89, #$, #), #8, #", #9, "$, "#, :$, :#, 9$, 9#, ($, (#,5$$,5$#, 55$, 55#, 5)$, 5)#, 5*$, 5*#, 58$, 58#, 5#$, 5##, 5"$, 5"#, 5:$, 5:#, 59$, 59#,

5($, 5(#, )$$, )5$, ))$, )*$, )8$, )#$, )"$, ):$, )9$, )($, *$$, *5$, *)$, **$, *8$, and

*#$.

*.5 ;esign of 0iston

&onsidering diameter of piston as 5$$ mm, and material is cast iron piston. or 5# kw

power and speed as ))$$ rpm. Assuming re!uired data

*.) 0iston headC

6ased on strength consideration, the thickness of piston head is given byCt QUV'*0in ;W / '5" 3tpX

**


34/93

=here

0in Q >aximum gas pressure, in '2/mmW Q # >pa

; Q ;iameter of piston or &ylinder bore, in 'mm Q 5$$ mm

3tp Q Allowable tensile stress of piston material,

Q *:.# 2/mmW for &ast Iron

t Q U V'*S#S5$$W / '5"S *:.#X Q 5" mm

6ased on eat dissipation the head thickness is determined asC

t Q V'5$$$ / '5).#"+ 'Tc-TeX QV'5$$$S#8)5.9/

'5).#"S8"."(S5$]WS')$#XQ 58.:9mm

=here

Q eat flowing through the head '+=

Q & S m S &v S 0 bQ$.$#S$.5#S88S5$YS5:.):9 Q #8)5.9 +/h

& Q &onstant Q $.$#

m Q mass of the fuel used 'i.e. fuel consumption, in '+ g/+=/3 Q $.5#

+ g/+w/h

&v Q igher &alorific value of the uel Q 88 x 5$Y +Z/+ g for ;iesel

0 b Q 6rake power of the 1ngine per cylinder '+=

Q V'0?An / '"$x5$YX Q V'$.#S5)$S5$]*S$.$$:9#S))$$ / '"$S5$YX

Q5:.):9kw

0 Q 6rake mean effective pressure Q $.# >pa

? Q 3troke length Q 5)$ mm

A Q Area of the piston at its top side, in 'mmW Q '`/8S5$$WQ$.$$:9#mW

n Q 2umber of power strokes per minute Q 5

k Q eat conductivity factor '+=/m/\&

Q 8"."x5$]Y for &ast Iron

Tc Q Temperature at the centre of piston head '\&

Te Q Temperature at the edge of piston head '\& Q )$#\& for cast iron

*.*


35/93

6ottom rings Q 5

0c Q contact pressure 'i.e. wall pressure, in 2/mmW Q $.5$* 2/mmW.

2ow, the radial thicknessC

t* Q 5$$U V'*S$.5$* / ($X Q " mm

And the axial thickness

t8 Q '$.: to 5 S" Q #mm

3 br Q allowable bending stress for ring material '2/mmWQ ($ 2/mmW for&I

The first ring groove distance Q t5 to 5.)t5Q5" from the top.

The lands between the rings Q '$.:# to 5 t8Q 8mm

The gap between the free ends of the ring is taken as & Q '*.# to 8 t *Q))mm

0iston barrelC

The maximum thickness of barrel nearer to piston head is given by

t# Q $.$*;^b^$.# Q $.$*S5$$ ^ " ^$..# Q ".8mm

=here b Q


36/93

0n Q Allowable bearing pressure of piston Q)#2/mmW

6eing strength of piston pin

b Q bearing pressure S proected area Q 0 bSS d

6y e!uating this being pressure to gas force

0 SS d Q gG *():$/8#S)# Q d p

=here g Q '`/8 S ;W S 0m

Ksually /d Q5.# to )

The piston is checked for bending, as the induced 6ending stress,

> Q bending moment Q 'g S ;/9Q *():$S5$$/9Q8($9:#2-mm

3 b Q allowable bending stress

Q 8$ 2/mmW for heat treated alloy steel

3 b Q V'*) >/ `dYX 3 b Q 8($9:#S*) / `S*#Y Q 55".") 2/mmW58$> pa

which is design is safe. 'Theoretically

0


37/93


38/93

STRUCTURAL

5oungs 3o&u!us %.%eDD8 3Pa

Poissons Ratio D.+>

#ensit? :.+e)DD9 *gmm

Therma! Epansion %.%e)DD8 %HC

T"ER3AL

Therma! Con&u'ti


39/93

0ro/12I211/&A1 solution,

is used by discrete manufacturers for mechanical engineering, design and

manufacturing. 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 optimiFation 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 !uickly optimiFe the design, or where the

resulting geometry may be complex or based upon e!uations.

0ro/12I211< provides a complete set of design, analysis andmanufacturing capabilities on one, integral, scalable platform. These capabilities

include 3olid >odeling, 3urfacing,


40/93

0rimary uses of solid modeling are for &A;, engineering analysis, computer

graphics and animation, rapid prototyping, medical testing, product visualiFation and

visualiFation of scientific research.

A solid model generally consists of a group of features, added one at a time,

until the model is complete. 1ngineering solid models are built mostly with sketcher-

based featuresG )-; sketches that are swept along a path to become *-;. These may be

cuts, or extrusions for example.

Another type of modeling techni!ue is JsurfacingJ 'reeform surface

modeling. ere, surfaces are defined, trimmed and merged, and filled to make solid.

The surfaces are usually defined with datum curves in space and a variety of complexcommands. 3urfacing is more difficult, but better applicable to some manufacturing

techni!ues, like inection molding. 3olid models for inection molded parts usually

have both surfacing and sketcher based features. 1ngineering drawings are created

semi-automatically and reference the solid models.

#.8 ;etailed procedure of modeling of the pistonC-

@pen the pro-engineer software and initially take the DpartE module.

After entering in to the part module we will observe some plane named as front, right

and top.

Then take DrevolveE operation to generate the model. After taking the command select

any one of the desired plane and create the sketch by using sketcher tools.

8$

http://en.wikipedia.org/wiki/Engineering_drawinghttp://en.wikipedia.org/wiki/Engineering_drawinghttp://en.wikipedia.org/wiki/Engineering_drawing


41/93

Fig %D$ s*et'h of piston in pro)engineer


42/93

inally fillet operation was performed at the desired locations in the piston model.

Fig %+$ fina! piston mo&e! in pro)engineer

I2IT1 1?1>12T >1T@;

".5 Introduction

inite 1lement Analysis '1A is a computer-based numerical techni!ue for

calculating the strength and behavior of engineering structures. It can be used to

calculate deflection, stress, vibration, buckling behavior and many other phenomena.

It can be used to analyFe either small or large-scale deflection under loading or

applied displacement. It can analyFe elastic deformation, or Npermanently bent out of

shapeN plastic deformation. The computer is re!uired because of the astronomical

number of calculations needed to analyFe a large structure. The power and low cost of

modern computers has made inite 1lement Analysis available to many disciplines

and companies.

In the finite element method, a structure is broken down into many small

simple blocks or elements. The behavior of an individual element can be described

8)


43/93

with a relatively simple set of e!uations. Zust as the set of elements would be oined

together to build the whole structure, the e!uations describing the behaviors of the

individual elements are oined into an extremely large set of e!uations that describe

the behavior of the whole structure. The computer can solve this large set of

simultaneous e!uations. rom the solution, the computer extracts the behavior of the

individual elements. rom this, it can get the stress and deflection of all the parts of

the structure. The stresses will be compared to allowed values of stress for the

materials to be used, to see if the structure is strong enough.

The term Nfinite elementN distinguishes the techni!ue from the use of

infinitesimal Ndifferential elementsN used in calculus, differential e!uations, and

partial differential e!uations. The method is also distinguished from finite differential

e!uations, for which although the steps into which space is divided are finite in siFe,

there is little freedom in the shapes that the discreet steps can take. inite element

analysis is a way to deal with structures that are more complex than can be dealt with

analytically using partial differential e!uations. 1A deals with complex boundaries

better than finite difference e!uations will, and gives answers to Nreal worldN

structural problems. It has been substantially extended in scope during the roughly 8$

years of its use.

".) C

Applications of the 1> can be divided into three categories, depending on

the nature of the problem to be solved. In the first category, is all the problems known

as e!uilibrium problems or time independent problems. or the solutions of

e!uilibrium problems in the solid mechanics area, we need to find pressure, velocity,

temperature and sometimes concentration distributions under steady state conditions.

In the second category, are the so-called 1igen value problems of solid and

fluid mechanics, These are steady state problems whose solution often re!uires the

determination of natural fre!uencies and mode vibration of solids and fluids.

1xamples of 1igen value problems involving both solid and fluid mechanics appear in

civil engineering when the interaction of lakes and dams is considered and in

8*


44/93

aerospace engineering when sloshing of li!uid fuels in the flexible tanks is involved.

Another class of 1igen value problems includes the stability of the laminar flows.

In the third category, is the multitude of time dependent or propagation

problems of continuum mechanics, this category is composed of problems, which

result when time dimension is added to the problems of the first two categories. In the

finite displacement method, displacement measures at discrete points in the body are

taken as the unknowns and the displacement field is derived in terms of these discrete

variables. @nce the discrete displacements are known, the strains are evaluated from

the strain displacement relations and finally the stresses are determined from the

stress-strain relations.

In the finite displacement method superposing the contribution of the element

stiffness matrices at each node forms the stiffness matrix for structure. The system

load vector is generated in a similar way, i.e. by superposing the element force

vectors. The displacement boundary conditions are then enforced. These steps result

in set of algebraic e!uations relating the displacement measures.

=ith the advancement in computer technology and &A; systems, complex problems

can be modeled with relative ease. 3everal alternate configurations can be tried out

before the first prototype is built. 3o by this method an approximate behavior of the

continuum can be determined which would greatly help in better design.

1> is widely used in almost all fields of science and engineering. It is used

to analyFe problems of structural, heat transfer, fluid flow, seepage, lubrication,

electric and magnetic fields, fracture mechanics and in many other fields. 2umerous

software packages based on 1> or 1A have been developed such as 2A3Techanics

';eflection 3tress Analysis

of structures In plane stresses, stretching of plates, gravity

88


45/93

A. Two dimensional analysis

6. Three dimensional analysis

dams, Axi-symmetric solids and shells, rocks,

motors machine parts such as shafts, beams

bridges etc

*-; trusses, space frames such as cranes, thin

walled structure like machine tools,

transmission towers, nuclear towers, nuclear

reactors, ship structures, radar domes,

building dams, shell roofs, arches, drilling

platforms etc.). 3oil and echanics oundation layers, rock oints. 0avements,

3tability of excavation such as river banks,

1mbankments, @pen pit and underground

mining problems etc.*. Thermal analysis and luid Transient and steady state temperature

distribution, thermal strain and stresses in

mechanical and civil structures, flow towards

wells, seepage through foundations, luid

flows in pipes, canals etc.8. ydro-1lasticity ydrodynamic, hydrostatic and air bearings,

reservoir-dam interactions, sloshing of li!uids

in flexible containers etc.

#. ;ynamics 2atural fre!uencies and mode shapes of

structures.


46/93

The steps in the finite element method when it is applied to structural mechanics are

as follows.

;ivide the continuum into a finite number of sub regions 'or elements of simple

geometry such as line segments, triangles, !uadrilaterals '3!uare and rectangular elements are subset of !uadrilateral, tetrahedrons and hexahedrons 'cubes etc.

3elect key point on the elements to serve as nodes where conditions of

e!uilibrium and compatibility are to be enforced.

Assume displacement functions with in each element so that the displacements at

each generic point are depending upon nodal values.

3atisfy strain displacement and stress B strain relationship within a typical

element. ;etermine stiffness and e!uivalent nodal loads for a typical element using work

or energy principles.

;evelop e!uilibrium e!uations for the nodes of the discredited.

&ontinuum in terms of the element contributions.

3olve the e!uilibrium for the nodal displacements.

The basic premise of the 1> is that a solution region can be analytically

modeled or approximated by replacing with an assemblage of discrete elements. 3ince

these elements can be put together in a variety of ways, they can be used to represent

exceedingly complex shapes. The important feature of the 1>, which sets it apart

from the other approximate numerical methods, is the ability to format solutions for

the individual element before putting them together to represent the entire problem.

Another advantage of 1> is the variety of ways in which one can formulate the

properties of individual elements.

".8 1> can be broadly classified in toC

5. 0re-processing

). 0rocessing 'solution

*. 0ost-processing

a 0re-processingC

It consists of solid model generation and discretiFation that in to finite elements.;efinition of properties of modal such as element type, material properties, various

8"


47/93

constants such as youngLs modulus, 0oisson ratio etc., dimension of each element i.e.,

thickness, moment of inertia, area etc.

eneration of elementC two different methods are used in generating the elements.

5. ;irect generation

). rom solid model

In direct generation method, the node is defined first and the elements are

interconnected to obtain the final model.

In solid generation method solid model is generated and then, model is divided

into finite elements. This conversion of solid model to finite elements is done through

mesh generation. This method is more useful for complex models. In the present

work solid generation method is used for making 1> models.

1lements from solid model method can be subdivided into two categories.

• ree meshing.

• >apped meshing.

ree meshingC

ree meshing allows more flexibility in defining mesh areas. ree mesh

boundaries can be much more complicated than mapped mesh with out subdividing in

to multiple regions. The mesh will automatically be created by an algorithm that tries

to minimiFe element distortion 'deviation from a perfect s!uare. ree mesh surfaces

can easily have internal holes, where mapped mesh surfaces canLt. ree meshing is

controlled by two parameters assigned to each mesh surface or volume that affect the

siFe of the elements generated. The first is the element length, which is the normal

siFe of elements the program will attempt to generate. The second parameter controls

mesh refinement at curves in the model by controlling how much deviation is allowed

between straight element sides and curved boundaries. This parameter is expresses

either as a percentage deviation or an absolute number.

>apped meshingC

8:


48/93

>apped meshing re!uires the same number of elements on opposite sides of the

mesh area, and re!uires that mesh area be bounded by three or four DedgesE. If you

define a mapped mesh area with more than four curves, you must define which

vertices are topological corners of the mesh. >apped mesh boundaries with three

corners will generate triangular elements in on DdegenerateE corner. The number of

elements per edge and biasing of elements of elements of element siFe towards the

end or the center of edges control the mesh density. Another advantage of mapped

meshing is we can produce dense mesh where we are interested and can produce

coarse mesh where we are not interested even though it is of curved structure.

".# T1 A2A?43I3 0


49/93

step is the assessment of the modeling and discretiFation errors indicated in ig. 'The

solution error is generally unimportant.

"." A2343 =ork 6ench 55.$

A2343 is an integrated design analysis tool based on the > developed by

A2343, inc. it has its own tightly integrated pre-and post-processor. The A2343

product documentation is excellent and it includes commands reference, operations

guide, modeling and meshing guide, basic analysis procedures guide, advanced

analysis guide, element reference, structural analysis guide, thermal analysis guide,

fluid dynamics guide, and coupled field analysis guide.

1ngineering capabilities of A2343 products areC

3tructural analysisC linear stress, nonlinear stress, dynamic, buckling.

Thermal analysisC steady state, transient, conduction convention, radiation, and

phase changeG &; analysis, steady state, transient, incompressible, compressible,

laminar, turbulent, electromagnetic fields analysis, magneto-staticLs, electrostatics,

ield and coupled field analysisC acoustics, fluid-structural, fluid-thermal,

magnetic-structural, magnetic-thermal, pieFoelectric, thermal-electric, thermal-

structural, electric-magnetic, sub-modeling, optimiFation, and parametric designlanguage.

1lement library in A2343 lists 59( finite elements. They are broadly grouped

intoC ?I2+, 0?A21, 61A>, 3@?I;, &@>6I2, 0I01, >A33, 31??, ?KI;,

>AT


50/93

2onlinearities can include plasticity, stress stiffening, large deflection, large

strain, hyper elasticity, contact surfaces, and creep.

*. >ode fre!uency analysisC Ksed to calculate the natural fre!uencies and mode

shapes of a structure. ;ifferent mode extraction methods are available.

8. armonic response analysisC Ksed to determine the response of a structure to

harmonically time varying loads.

#. 6uckling analysisC Ksed to calculate the buckling loads and determine the

buckling mode shape. 6oth linear '1igen value buckling and nonlinear

buckling analyses are possible.

". Thermal analysisC A thermal analysis calculates the temperature distribution

and related thermal !uantities in a system or component.

Typical thermal !uantities of interest areC

The temperature distributions

The amount of heat lost or gained

Thermal gradients

Thermal fluxes.

Thermal simulations play an important role in the design of many engineering

applications, including internal combustion engines, turbines, heat exchangers, piping

systems, and electronic components. In many cases, engineers follow a thermal

analysis with a stress analysis to calculate thermal stresses 'that is, stresses caused by

thermal expansions or contractions.

A2343 supports two types of thermal analysisC

5. A steady-state thermal analysis determines the temperature distribution and other

thermal !uantities under steady-state loading conditions. A steady-state loadingcondition is a situation where heat storage effects varying over a period of time can be

ignored.

). A transient thermal analysis determines the temperature distribution and other

thermal !uantities under conditions that vary over a period of time.

3teady-3tate Analysis

The A2343 >ulti physics, A2343 >echanical, A2343 ?@T


51/93

1ngineer/analysts often perform a steady-state analysis before doing a transient

thermal analysis, to help establish initial conditions. A steady-state analysis also can

be the last step of a transient thermal analysis, performed after all transient effects

have diminished. 4ou can use steady-state thermal analysis to determine temperatures,

thermal gradients, heat flow rates, and heat fluxes in an obect that are caused by

thermal loads that do not vary over time. 3uch loads include the followingC

&onvections


52/93

;isplacements 'KR, K4, KP, 4, >P

These are concentrated loads usually specified on the model exterior. The directions

implied by the labels are in the nodal coordinate system.

0ressures '00

These are applied to study the effects of thermal expansion or contraction 'that

is, thermal stresses.

".: Advantages of inite 1lement >ethod '1> / inite 1lement

Analysis '1A

The finite element method '1> has now become a very important tool of

engineering analysis. Its versality is reflected in its popularity among engineers and

designers belonging to nearly all the engineering disciplines. =hether a civil engineer

designing bridges, dams or a mechanical engineers designing auto engines, rolling

mills, machine tools or an aerospace engineer interested in the analysis of dynamics of

an aeroplane or temperature rise in the heat shield of a space shuttle or a metallurgist

concerned about the influence of a rolling operation on the microstructure of a rolled

product or an electrical engineer interested in analysis of the electromagnetic field in

electrical machinery-all find the finite element method handy and useful. It is not that

these problems remained unproved before the finite element method came into vogueG

rather this method has become popular due to its relative simplicity of approach and

accuracy of results.

Traditional methods of engineering analysis, while attempting to solve an

engineering problem mathematically, always try for simplified formulation in order to

#)


53/93

overcome the various complexities involved in exact mathematical formulation. In the

modern technological environment the conventional methodology of design cannot

compete with the modern trends of &omputer Aided 1ngineering '&A1 techni!ues.

The constant search for new innovative design in the engineering field is a common

trend.

To build highly optimiFed product, this is the basic re!uirement of today for

survival in the global market today. All round efforts were put forward in this

direction. 7arious design packages have been developed by software professional and

technologists.

A more subtle attribute of 1> is its ability to deal with complex material models.

or example, the heterogeneous, anisotropic, nonlinear, inelastic models of laminated

composite materials and sandwich cons$truction are handled without any significant

expansion of the cost or complexity of the numerical simulation process.

1> brings a number of special advantages to coupled thermal-structural analysis.

A consistent methodology of finite element heat transfer analysis is available for the

computation of temperature distribution in solids and structures. It is possible to use

the same general-purpose 1A program to predict both temperature distribution due

to thermal input and thermal stresses arising from these temperatures. Also, in cases

where the material properties are a function of temperature, it is possible to assign

material properties to each finite element consistent with the temperature level of that

element.

It is a revolution you must be familiar with-the marriage of personal computers

and finite element analysis programs. @ver thirty-five 0&-based 1> systems are

currently available in the market of theses, some stand out as market leaders based on

their performance, popularity and advertising. =hat makes 1A on a 0& so successful

is its affordability. This will change the face of engineering design in general andstructural and mechanical design in particular. Technically, the siFe of a finite element

model that 0& can handle is limited only by the capacity of the hard disk. 6est of all,

a 0&-based 1> system is an excellent training tool for teaching 1>.

• Re&u'e &e


54/93


55/93

• 3ame topology as in real life. 2ot limited to blocks with defined flow direction

• 1xtensive and expandable libraries of predefined and user-defined components

and blocks

• Ability to manage complex designs by segmenting models into hierarchies of

design components

".( 0erforming a Typical A2343 Analysis

The A2343 program has many finite element analysis capabilities, ranging

from a simple, linear, static analysis to a complex, nonlinear, transient dynamic

analysis.

".5$ A typical A2343 analysis has three distinct stepsC

• 6uild the model.

• Apply loads and obtain the solution.

•


56/93

Fig %/$ so!i& 8 E!ement

3olid element (# is a )$-node brick element. It also supports a prism, pyramid,

and tetrahedral element shape option. The tetrahedral formed at the interface with

brick elements do not have mid-side nodes where they would not exist on the

matching brick elements, so there should not be a big mismatch problem at the

interface.

These elements that have a mid-side node missing are considered to be

degenerate forms in the A2343 manuals, and are not recommended in regions with

high stress gradients, or where exact stress values are important.

#"


57/93

Fig %8$ #ra(ing of piston

Fig %9$ After Importing Piston from Pro)E to Ans?s 0or* Ben'h

Fig %:$ Piston after 3eshing In ANS5S

#:


58/93

:.% Ana!?sis for a!uminum a!!o? piston hea&s$

STRUCTURAL ANAYLSIS

MATERIAL DATE:

Ta!e 9$ A!uminum A!!o? J Constants

tructural Analysis

5oungs 3o&u!us :%DDD 3Pa

Poissons Ratio D.

#ensit? +.::e)DD9 *gmm

Ta!e :$ Stati' Stru'tura! J Loa&s

#9


59/93

OKe't Name Pressure

Fixed upport

S'ope

S'oping

3etho&Geometr? Se!e'tion

Geometr? + Fa'es / Fa'es

#efinition

#efine B? Norma! To

T?pe Pressure Fie& Support

3agnitu&e +D 3Pa

Fig %>$ Figure Sho(s the Boun&ar? Con&itions App!ie& For Piston

#(


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Fig %$ Figure Sho(s Stru'tura! Loa& A'ting On The Piston "ea&.

"$


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Fig +D$ Tota! #eformation for Con'a


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Fig ++$-Eui


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Fig +$)Tota! #eformation In The Con


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Fig +8$ Eui


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Fig +:$-Eui$ Eui


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0 5 10 15 20 25

0

50

100

150

200

250300

350

400

450

Total deformation

stress

strain

Graph $ Graph Of F!at Shape& Piston Cro(n "a$ A!uminum A!!o? J Constants

Stru'tura!

5oungs 3o&u!us :%DDD 3Pa

Poissons Ratio D.

#ensit? +.::e)DD9 *gmm

Therma! Epansion +.e)DD8 %HC

Therma!

Spe'ifi' "eat >:8. 2*gHC

Ta!e $ Stea&?)State Therma! J Loa&s

OKe't Name Convection Convection 2

""


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S'ope

S'oping 3etho& Geometr? Se!e'tion

Geometr? + Fa'es % Fa'e

#efinition

T?pe Con


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Fig D$-Eui


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Fig %$ Temperature #istriution for Con


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50 100 150 200 250 300 3500

50

100

150

200

250

300

Maximum

temperature

Minimum temperature

Graph 8 $ Graph Of Con


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Fig /$-Eui


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The above analysis results of the piston with different crown shapes were tabulated

bellow.Ta!e %D$ Fina! Resu!ts Of #ifferent Cro(ns for a!uminum a!!o?

Shape of 'ro(n Con


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Temperature C

3aimum

3inimum

+9D.D>

%D.+%

+9.DD

%.:

+9+.:D

%+.8

Tota! "eat F!u(mm+;

3aimum

3inimum

D.D%9>%+

%.>99e)8

D.D%/88:

%.+/>e)8

D.D%:%9

%.D9:/e)8

:.+ Ana!?sis for 'ast iron piston hea&s

STRUCTURAL ANAYLSIS

MATERIAL DATE:

Ta!e %% $ 'ast iron J Constants

:*


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tructural Analysis

5oungs 3o&u!us 1.1e+005 MPa

Poissons Ratio 0.28

#ensit? 7.2e-006 kg/mm³

Ta!e %+$ Stati' Stru'tura! J Loa&s

OKe't Name Pressure Fixed upport

S'ope

S'oping

3etho&Geometr? Se!e'tion

Geometr? + Fa'es / Fa'es

#efinition

#efine B? Norma! To

T?pe Pressure Fie& Support

3agnitu&e +D 3Pa

Fig 8$ Figure Sho(s the Boun&ar? Con&itions App!ie& For Piston

:8


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Fig 9$ Figure Sho(s Stru'tura! Loa& A'ting On The Piston "ea&.

Fig :$ Tota! #eformation for Con'a


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Fig >$-Eui


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Fig $-Eui


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Fig /%$-Eui


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0 5 10 15 20 25

0

50

100

150

200

250

300

350

400

450

total deformation

strain

stress

Graph >$ Graph Of Con


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Fig //$-Eui


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0 5 10 15 20 25

0

50

100

150

200

250

300

350

400

450

total deformation

strain

stress

Graph $ Graph Of f!at Shape& Piston Cro(n "a


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#efinition

T?pe Con


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Fig /:$ Tota! heat f!u for 'on'a


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Fig />$ Temperature #istriution for 'on


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Fig /$ Tota! heat f!u for 'on


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Fig 8D$ Temperature #istriution for f!at Shape& Cro(n Piston.

Fig 8%$ Tota! heat f!u for F!at Shape& Cro(n Piston.

50 100 150 200 250 300 350

0

50

100

150

200

250

300

maximum

minimum

Graph %+$ Graph Of F!at Shape& Piston Cro(n "a


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The above analysis results of the piston with different crown shapes were tabulated bellow.

Ta!e %8$ Fina! Resu!ts Of #ifferent Cro(ns for 'ast iron

Shape of 'ro(n Con .

Temperature C

3aimum

3inimum

+>D

%+9

+>+

%+>

+>D

%+>

Tota! "eat F!u(mm+;

3aimum

3inimum

D.D%D8

%.+8e)9

D.D%DD>

%.9:e)9

D.%D8

%.+8e)9

#ISCUSSION

The alloy from which a piston is made not only determines its strength and

wears characteristics, but also its thermal expansion characteristics. otter engines

re!uire more stable alloys to maintain close tolerances without scuffing.

The main factors influencing on piston areC

3trength and rigidity of head thickness

eat distribution of piston material

If the calculated stresses are too great, it is necessary to change piston design. 3uch

changes may beC

Increasing the piston head thickness

&hanging the piston crown shape

9:


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&hanging the material

?ength of piston

0iston rings

CO3PARISION OF RESULTS$

Shape of 'ro(n Con .Temperature C

3aimum

3inimum

+>D

%+9

+>+

%+>

+>D

%+>

Tota! "eat F!u(mm+;

3aimum

3inimum

D.D%D8

%.+8e)9

D.D%DD>

%.9:e)9

D.%D8

%.+8e)9

Ta!e $ Fina! Resu!ts Of #ifferent Cro(ns for 'ast iron

Shape of 'ro(n Con

%D.+%

+9.DD

%.:

+9+.:D

%+.8

99


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Tota! "eat F!u(mm+;

3aimum

3inimum

D.D%9>%+

%.>99e)8

D.D%/88:

%.+/>e)8

D.D%:%9

%.D9:/e)8

Ta!e $ Fina! Resu!ts Of #ifferent Cro(ns for A!uminium a!!o?

CONCLUSION

In our proect we have designed a piston used in two wheeler and modeled in

*; modeling software 0


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• 6y comparing results of both the materials aluminum alloy and cast iron , the

obtained results such as von miss stresses, total deformation, and thermal heat

transfer are within the safe Fone of standard for three shapes of crown.• 3o, far the taken bore siFes the obtained results are within the standard and

design is safe. inally the convex shape crown piston is having better design

because of the stresses are low compared to aluminium alloy and heat flux

generated is also low.• 6y changing piston materials with different compositions we can design the

piston according to their strength and heat fluxes are can also be done by using

1>.• =e &onclude analyFe the thermal stress distribution of piston at the real

engine condition during combustion process.

REFERENCES

Introduction to physical metallurgy - 3idney Avener

>achine design - 3.>d. Zalaluddin

>achine design - ;r. 3adhu 3ingh

($


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0roduction ;rawing - +.?.2arayana, 0.+annaiah,

+.7enkata achines - Abdulla 3hariff

Theory of >achines - 3.3. ierbach, D0roceedings of the A3>1 Internal

&ombustion 1ngine ;ivision )$$( 3pring Technical &onferenceE, I&13)$$(

>ay *-", )$$(, >ilwaukee, =isconsin, K3A.

(5


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0.ustof, A.ornik, DInternational Zournal of Achievements in >aterials and

>anufacturing 1ngineeringE, 7ol. *# Issue ) August )$$(.

Tulus, Ariffin, A. +., Abdullah, 3. and >uhammad. 2. D0roceedings of the )nd

I>T-T athematics, 3tatistics And Applications

Kniversity 3ains >alaysiaE, Zune 5*-5#, )$$".

3anay 3hrivastva, +amal 3hrivastava, echanical

1ngineering, ashemite Kniversity, Par!a 5*55#, ZordanE, Institution of

>echanical 1ngineers, ?ondon, pp. 5**B58#.

Ashwinkumar 3. ;hoble,

()


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0. &arvalheira5, and 0. onalves, 1A of Two 1ngine 0istons >ade of

Aluminium

&ast Alloy A*($ and ;uctile Iron "#-8#-5) Knder 3ervice &onditions, #th

International &onference on >echanics and >aterials in ;esign 0orto-0ortugal,

)8- )", pp .5-)5, )$$".

udimetal 0. opinath &.7. inite 1lement Analysis of ongkutLs Kniversity of Technology

2orth 6angkok 0ress, 6angkok, Thailand AIZ3T0>1, 7ol. )'8, pp 9#-(),

)$$(.

Design and Prototyping of Piston

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