International Journal of Research ISSN NO:2236-6124ijrpublisher.com/gallery/6-january-2019.pdf · 2019-01-02 · FATIGUE ANALYSIS OF A HELICAL GEAR USED IN MARINE APPLICATIONS ABSTRACT

“FATIGUE ANALYSIS OF A HELICAL GEAR USED IN MARINE APPLICATIONS”

Author-1NELAGONDARASHI CHANDRA SHEKAR M.Tech

Assistant Professor

Dept:(Mechanical Engineering)

Email: [email protected]

Mobile: 9701916138

Sri Indu Institute of engineering & Technology,

Sheriguda, Hyderabad.

Author-2 MANDA SANDEEPM.Tech

Assistant Professor

Dept :(Mechanical Engineering)

Email:[email protected]

Mobile:9494924307



Author-3:Dr I. SATYANARAYANA

Professor, principal

M-Tech(IIT-KGP), Ph.D., MIE, MISHMT

Email Id: [email protected]

Mobile:9502997013



International Journal of Research

Volume VIII, Issue I, January/2019

ISSN NO:2236-6124

Page No:55

FATIGUE ANALYSIS OF A HELICAL GEAR USED IN MARINE

APPLICATIONS

ABSTRACT

Gear is a machine element used to transmit motion and power between rotating shafts by means of progressive engagement of

projections called teeth. Generally gear transmits motion or power between rotating shafts when the centre between two shafts is

comparatively low.

In helical gears, the leading edges of the teeth are not parallel to the axis of rotation, but are set at an angle. Since the gear is

curved, this angling causes the tooth shape to be a segment.. The bending and surface strength of the gear tooth are considered to

be one of the main contributors for the failure of the gear in a gear set

The aim of the project is to design a helical gear for marine applications .the design is done on 3d modeling CATIA V5

software.

Structural analysis and Fatigue analysis are done using three materials Nickel Chromium Alloy steel , Aluminum Alloy A360

and titanium . Structural analysis is done to validate the strength. Fatigue is the progressive and localized structural damage that

occurs when a material is subjected to cyclic loading. The nominal maximum stress values are less than the ultimate tensile

stress limit, and may be below the yield stress limit of the material.

The analysis is done on ANSYS software.

INTRODUCTION TO GEARS

Gears are one of the most critical components in

mechanical power transmission systems. The bending

and surface strength of the gear tooth are considered to

be one of the main contributors for the failure of the gear

in a gear set. Understanding of their behaviour becomes

essential to design and implement them effectively.

Thus, analysis of stresses has become popular as an area

of research on gears to minimize or to reduce the failures

and for optimal design of gears. This thesis investigates

the characteristics of involutes helical gear system

mainly focused on bending and contact stresses using

analytical and finite element analysis. A rigid multibody

model is required to be simulated. The model consists of

a helical gear pair where Gear contact is characterized by

an angle-varying mesh stiffness and a backlash which

can lead to loss of the contact. Angle-varying mesh

stiffness shall be calculated using a finite element model.

CLASSIFICATIONS OF GEARS

SPUR GEAR

Spur gears have their teeth parallel to the axis and are

used for transmitting power between two parallel shafts.

They are simple in construction, easy to manufacture

and less cost. They have highest efficiency and

excellent precision rating. They are used in high speed

and high load application in all types of trains and a

wide range of velocity ratios. Hence, they find wide

applications right from clocks, household gadgets,

motor cycles, automobiles, and railways to aircrafts

SPUR GEAR

HELICAL GEAR

Helical gears are used for parallel shaft drives. They have

teeth inclined to the axis as shown in Fig. 2 Hence for the

same width; their teeth are longer than spur gears and have

higher load carrying capacity. Their contact ratio is higher

than spur gears and they operate smoother and quieter than

spur gears. Their precision rating is good. They are

recommended for very high speeds and loads. Thus, these

gears find wide applications in automotive gearboxes.

Their efficiency is slightly lower than spur gears. The helix

angle also introduces axial thrust on the shaft.



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DOUBLE HELICAL GEAR OR HERRINGBONE GEARDouble helical or Herringbone gears used for

transmitting power between two parallel shafts. They have

opposing helical teeth with or without a gap depending on

the manufacturing method adopted, Fig 3. Two axial

thrusts oppose each other and nullify. Hence the shaft is

free from any axial force. Though their load capacity is

very high, manufacturing difficulty makes them costlier

than single helical gear. Their applications are limited to

high capacity reduction drives like

that of cement mills and crusher

DOUBLE HELICAL GEARSTRAIGHT BEVEL

GEARS

Straight bevel gears are used for transmitting power between

intersecting shafts,. They can operate under high speeds and

high loads. Their precision

rating is fair to good. They

are suitable for 1:1 and higher velocity ratios and for right-

angle meshes to any other angles. Their good choice is for

right angle drive of particularly low ratios. However,

complicated both form and fabrication limits achievement of

precision. They should be located at one of the less critical

meshes of the train. Wide application of the straight bevel

drives is in automotive differentials, right angle drives of

blenders and conveyors.

SPIRAL GEARS Spiral gears are also known as crossed helical gears, They

have high helix angle and transmit power between two

nonintersecting non-parallel shafts. They have initially point

contact under the conditions of considerable sliding velocities

finally gears will have line contact. Hence, they are used for

light load and low speed application such as instruments,

sewing machine etc. The characteristics of these various gear

types are discussed in most mechanical design texts Like all

components, gears can and do fail in application. From the

above discussion meshing stiffness analysis of helical gear in

dynamic condition is very important.

SUMMARY AND EVALUATION OF GEAR TYPES

Type

Features and

Precision

Rating

Applications

Comments Regarding

Precision

Spur Parallel

Shafting.

High speeds

and loads

highest

efficiency

Precision

Rating is

excellent

Applicable to

all types of

trains and a

wide range of

velocity ratios .

Simplest tooth

elements offering

maximum precision.

First choice,

recommended for all

the gear meshes,

except where very

high speeds and loads

or special features of

other types, such as

right angle drive,

cannot be avoided.

Helical

Parallel

Shafting.

Very high

speeds and

loads.

Efficiency

slightly less

than spur

mesh.

Precision

Rating is

good

Most

applicable to

high speeds

and loads; also

used whenever

spurs are used.

Equivalent quality to

spurs, except for

complication of helix

angle. Recommended

for all high-speed and

high-load meshes.

Axial thrust

component must be

accommodated.

Bevel

Intersecting

shafts,

High speeds,

High loads.

Precision

Rating is fair

to good.

Suitable for

1:1 and higher

velocity ratios

and for right-

angle meshes

(and other

angles)

Good choice for right

angle drive,

particularly low ratios.

However complicated

both form and

fabrication limits

achievement of

precision. Should be

located at one of the

less critical meshes of

the train.

SUMMARY AND EVALUATION OF GEAR TYPES

In the evaluation of helical gear designs, certain basic gear

design performance metrics such as tooth bending Stress,

Permissible bending stress, contact stress, bending fatigue

strength, allowable surface fatigue stress, Surface strength of

gear and pinion etc. are to be carefully considered. The

effectiveness of the helical gear design Can be improved only

when all these metrics are controlled properly. Gear designers

are constantly looking for Ways to improve effectiveness

through various techniques. Despite such attempts, the control

of all these metrics and achieving the desired performance is a

very complicated task. Therefore, there is great need for

detailed study of the intricacies of helical gear design especially

for different types of gear profiles.



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CROSSED HELICAL GEAR

The teeth on helical gears are cut at an angle to the face of

the gear. When two teeth on a helical gear system engage,

the contact starts at one end of the tooth and gradually

spreads as the gears rotate, until the two teeth are in full

engagement.

This gradual engagement makes helical gears operate much

more smoothly and quietly than spur gears. For this reason,

helical gears are used in almost all car transmissions.

Because of the angle of the teeth on helical gears, they

create a thrust load on the gear when they mesh. Devices

that use helical gears have bearings that can support this

thrust load.

One interesting thing about helical gears is that if the angles

of the gear teeth are correct, they can be mounted on

perpendicular shafts, adjusting the rotation angle by 90

degrees.

an attempt is made to study the performance of a

helical gear system for three different types of helical

gear systems namely single, herringbone and crossed

helical gear system. The objective of this work is to

conduct a comparative study on helical gear design

and its performance based on various performance

metrics through finite element as well as analytical

approaches. The theoretical analysis for a single

helical gear system Based on American Gear

Manufacturing Association (AGMA) a standard has

been assessed in Mat lab. The effect of Major

performance metrics of different helical gear tooth

systems such as single, The benefit of such a

comparison is quickly estimating the stress

distribution for a new design variant without carrying

out complex theoretical analysis as well as the FEA

analysis gives less scope for Manual errors while

calculating complex formulas related to theoretical

analysis of gears. It will significantly reduce

Processing time as well as enhanced flexibility in the

design performance.

The major cause of vibration and noise in a gear

system is the transmission error between the meshing

gears. By definition transmission error is the

difference between the theoretical and the actual

position between driving gear and the driven gear.

SPEED REDUCTION GEAR BOX

It can be defined also as the amount by which the ratio at

a given point in a revolution departs from the correct

ratio. For this reason, with prior knowledge of the

operating conditions of the gear set it is possible to

design the gears with minimum vibration and noise.

Mostly transmission error is due to two major causes.

The first cause is production incorrectness as well as

mounting mistake and the second one is caused by

elastic deflection at the time of loading.

Transmission error is considered as one of the

main contributor to noise and vibration in a gear system.

This suggests that the gear noise is closely related to

transmission error. If a pinion and a gear have ideal

involutes profiles running with no loading they should

theoretically run with zero transmission error. However,

when these same gears transmit torque, the joint torsion

mesh stiffness of each gear changes throughout the mesh

cycle as the teeth deflect causing variations in angular

rotation of the gear body.

Even though the transmission error is relatively

small these slight variations can cause noise at a

frequency which matches a resonance of the shafts or the

gear housing causes noise to be enhanced. This

phenomenon has been studied in order to minimize the

amount of transmission error in gears. Gearboxes of

construction vehicles and sites sustain a variety of faults

such as broken-shafts, eroded, broken, or missing teeth,

and even broken-cases because of heavy loads and harsh

working conditions. Early malfunction detection is

important to limit damage and avoid accidents. Generally,

casing mounted accelerometers are used to detect gear

faults based on vibration analysis techniques.

A gear is a rotating machine part having cut

teeth, or cogs, which mesh with another toothed part in

order to transmit torque. Two or more gears working in

tandem are called a transmission and can produce a

mechanical advantage through a gear ratio and thus may

be considered a simple machine. Geared devices can

change the speed, magnitude, and direction of a power

source. The most common situation is for a gear to mesh

with another gear, however a gear can also mesh a non-

rotating toothed part, called a rack, thereby producing

translation instead of rotation.

The gears in a transmission are analogous to the

wheels in a pulley. An advantage of gears is that the teeth of

a gear prevent slipping.

When two gears of unequal number of teeth

are combined a mechanical advantage is produced, with both



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the rotational speeds and the torques of the two gears

differing in a simple relationship.In transmissions which offer

multiple gear ratios, such as bicycles and cars, the term gear,

as in first gear, refers to a gear ratio rather than an actual

physical gear. The term is used to describe similar devices

even when gear ratio is continuous rather than discrete, or

when the device does not actually contain any gears, as in a

continuously variable transmission.

The earliest known reference to gears was

circa 50 A.D. by Hero of Alexandria, but they can be

traced back to the Greek mechanics of the Alexandrian

school in the 3rd century BC and were greatly developed

by the Greek polymath Archimedes (287-212 BC).

The motion from one shaft to another

shaft may be transmitted with belts, ropes and

chains. These methods are mostly used when the two shafts

are having long center distance. But if the distance

between the two shafts is very small, then gears are used to

transmit motion from one shaft to another. In case of belts

and ropes, the drive is not positive. There is slip and creep

that reduces velocity ratio. But gear drive is a positive and

smooth drive, which transmit velocity ratio. Gears are used

in many fields and under a wide range of conditions such

as in smaller watches and instruments to the heaviest and

most powerful machineries like lifting cranes. Gears are

most commonly used for power transmission in all the

modern devices. These toothed wheels are used to change

the speed or power between two stages (input and

output). They have gained wide range of acceptance in all

kinds of applications and have been used extensively in

the high speed marine engines. In the present era of

sophisticated technology, gear design has evolved to a high

degree of perfection.

The design and manufacture of precision cut

gears, made from materials of high strength, have made

it possible to produce gears which are capable

of transmitting extremely large loads at extremely high

circumferential speeds with very little noise, vibration and

other undesirable aspects of gear drives. Helical gears

are the modified form of spur gears, in which all the teeth

are cut at a constant angle, known as helix angle, to the

axis of the gear, where as in spur gear, teeth are cut

parallel to the axis. Helical gears are also employed to

transmit power between two shafts parallel to the axis.

The following are the requirements that must be met in the

design of gear drive. The gear teeth should have

sufficient strength, so that they will not fail under static and

dynamic loading during normal running conditions.

The gear teeth should have clear characteristics sothat their

life is satisfactory, the use of space and material should

be economical. The alignment of the gears and

deflections of the Shafts must be considered, because they

affect the Performance of the gears. The lubrications of

the gears must be satisfactory.

Currently the popular standards are ISO and

AGMA. These standards vary in selected approaches as

well as models and methods resulting in different design

solutions obtained for the same gear under the same set of

working conditions. Gear transmissions affect energy

consumption during usage, vibration, noise and warranty

costs among others factors. These factors are critical in

modern competitive, manufacturing, especially in

the aviation industry which demands exceptional

operations requirements concerning high reliability and

strength, low weight and energy consumption,

low vibrations and noise. Considering their reliability and

efficiency are some of the most important factors,

problems of distributions of loads and consequently,

distribution of stresses in the whole gear transmission,

particularly in teeth of mating gears,

need to be thoroughly analyzed. Gear transmissions

are widely used in various industries and their efficiency

and reliability are critical in the final product

performance evaluation.

The motion from one shaft to another

shaft may be transmitted with belts, ropes and chains.

These methods are mostly used when the two shafts are

having long center distance. But if the distance between the

two shafts is very small, then gears are used to transmit

motion from one shaft to another. In case of belts and

ropes, the drive is not positive. There is slip and creep that

reduces velocity ratio. But gear drive is a positive and

smooth drive, which transmit velocity ratio. Gears are used

in many fields and under a wide range of conditions such

as in smaller watches and instruments to the heaviest and

most powerful machineries like lifting cranes. Gears are

most commonly used for power transmission in all the

modern devices. They have been used extensively in the

high-speed marine engines. There is a great deal of

researches on gear analysis. Generally their major concerns

are on the analysis of gear stresses, transmission errors,

dynamic loads, noise, and failure of gear tooth, which are

very useful for optimal design of gear set. They have used

various approaches and means to attain their main

objectives.

APPLICATION OF HELICAL GEARS Helical gear applied in the industries comes in diverse

weight and sizes. There are many different types of helical

gears which can be used in different places. Therefore, the

application of helical gears is diverse, and we cannot give a

specific list. We can see that mechanical industry has a

quick development. It is no doubt that the market demands

for helical gears that are used in industrial applications are

increasing.

Obviously, the application of helical gears is quite large.

For example, they can be used in fertilizer industry,

railway industry, printing industry, and earth moving

industry, etc. Except for these industries, there are also

many others where helical gears can play a rather

important role. Then, let us see a few of the applications of

helical gears.

First, the earth moving industry: in our society especially

in cities, there are always a lot of constructions. In order to

fulfil these tasks, equipment and machinery are necessary.

These equipment’s require the need of helical gears. For

instance, helical gears like spur, helical, and planetary form

an integral part of the machinery and vehicles used in the

earth moving industry.

Second, the railway industry: railways are indispensable in

our society. In railways, there is a wide range of helical

gears and helical gear equipment’s used in different



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railway applications. For the special requirements of the

railways, the specialized helical gears are brought into use.

They are applied to achieve the certain purposes.

Third, the power industry:. In every process

of power generation and power transmission, helical gear

power transmission equipments have been used for a long

period of time. helical gear equipments support all

different aspects of the power generation process. helical

gear peripherals are used in different processes of power

generation, like in the gas turbine electric power

generation, coal-power electrical plants and so on.

MODES OF GEAR FAILURE

Solid Modeling It is the most perfect type of geometric model which is used

in CAD systems. It contains all the work frame and surface

geometry necessary to fully describe the edge and faces of

the model. In addition to the information related to the

geometry, it has information called topology that relates all

the geometry together. This intelligence makes operations

such a filleting and selecting an edge and also specifying a

radius.

Fully Associative A CATIA model is one which associates the drawings and

assembles it. When we Change Catia models geometry then

the models are automatically reflected in the associative

drawings and assemblies.

Constraints By which you can guarantee that design concepts such as

through holes and/or equal radii etc are captured and

maintained is called constraints. Parallel, perpendicular,

horizontal, vertical, etc know as geometrical constraint and

length, height, width, etc know as dimensional constaint.

Associativity: Associativity ensures that if any modification

is made in the model in any one of the workbenches of

CATIA V5, it is automatically reflected in the other

workbenches immediately.



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4.1 MODULES IN CATIA

Figure 1 MODEL OF HELICAL GEAR

• Sketcher

• Part Design

• Assembly Design

• Drafting

• Sheetmetal

Helical gear

Figure 2 MODEL OF HELICAL GEAR

DIFFERENT VIEWS AND DIMENSIONS OF

HELICAL GEAR

5. INTRODUCTION TO FEA

A wide range of objective functions (variables within the

system) are available for minimization or maximization:

• Mass, volume, temperature

• Strain energy, stress strain

• Force, displacement, velocity, acceleration

• Synthetic (User defined)

There are multiple loading conditions which may be

applied to a system. Some examples are shown:

• Point, pressure, thermal, gravity, and centrifugal

static loads

• Thermal loads from solution of heat transfer

analysis

• Enforced displacements

• Heat flux and convection

• Point, pressure and gravity dynamic loads

Each FEA program may come with an element

library, or one is constructed over time. Some sample

elements are:

• Rod elements

• Beam elements

• Plate/Shell/Composite elements

• Shear panel

• Solid elements

TYPES OF ENGINEERING ANALYSIS

Structural analysis consists of linear and non-linear

models. Linear models use simple parameters and assume

that the material is not plastically deformed. Non-linear

models consist of stressing the material past its elastic

capabilities. The stresses in the material then vary with the

amount of deformation as in.



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Vibration analysis is used to test a material against random

vibrations, shock, and impact. Each of these incidences may

act on the natural vibration frequency of the material which, in

turn, may cause resonance and subsequent failure.

Fatigueanalysis helps designers to predict the life of a

material or structure by showing the effects of cyclic loading

on the specimen. Such analysis can show the areas where crack

propagation is most likely to occur. Failure due to fatigue may

also show the damage tolerance of the material.

Heat Transfer analysis models the conductivity or thermal

fluid dynamics of the material or structure. This may consist of

a steady-state or transient transfer. Steady-state transfer refers

to constant thermo properties in the material that yield linear

heat diffusion.

5.2 RESULTS OF FINITE ELEMENT ANALYSIS

FEA has become a solution to the task of predicting

failure due to unknown stresses by showing problem areas in

a material and allowing designers to see all of the theoretical

stresses within. This method of product design and testing is

far superior to the manufacturing costs which would accrue if

each sample was actually built and tested.

In practice, a finite element analysis usually consists of three

principal steps:

1. Preprocessing: The user constructs a model of

the part to be analyzed in which the geometry is divided into a

number of discrete sub regions, or elements," connected at

discrete points called nodes." Certain of these nodes will have

fixed displacements, and others will have prescribed loads.

These models can be extremely time consuming to prepare,

and commercial codes vie with one another to have the most

user-friendly graphical “preprocessor" to assist in this rather

tedious chore. Some of these preprocessors can overlay a

mesh on a preexisting CAD file, so that finite element

analysis can be done conveniently as part of the computerized

drafting-and-design process.

2. Analysis: The dataset prepared by the preprocessor is

used as input to the finite elementcode itself, which constructs

and solves a system of linear or nonlinear algebraic equations

Kijuj = fi

Where u and f are the displacements and externally applied

forces at the nodal points. The formation of the K matrix is

dependent on the type of problem being attacked, and this

module will outline the approach for truss and linear elastic

stress analyses. Commercial codes may have very large

element libraries, with elements appropriate to a wide range

of problem types. One of FEA's principal advantages is that

many problem types can be addressed with the same code,

merely by specifying the appropriate element types from the

library.

3. Post processing: In the earlier days of finite

element analysis, the user would pore through reams of

numbers generated by the code, listing displacements and

stresses at discrete positions within the model. It is easy

to miss important trends and hot spots this way, and

modern codes use graphical displays to assist in

visualizing the results. A typical postprocessor display

overlays colored contours representing stress levels on

the model, showing a full field picture similar to that of

photo elastic or moiré experimental results.

6.1 GENERIC STEPS TO SOLVING ANY

PROBLEM IN ANSYS

Like solving any problem analytically, you need to

define (1) your solution domain, (2) the physical model, (3)

boundary conditions and (4) the physical properties. You

then solve the problem and present the results. In numerical

methods, the main difference is an extra step called mesh

generation. This is the step that divides the complex model

into small elements that become solvable in an otherwise

too complex situation. Below describes the processes in

terminology slightly more attune to the software.

Build Geometry Construct a two or three dimensional representation of

the object to be modeled and tested using the work plane

coordinate system within ANSYS.

Define Material Properties Now that the part exists, define a library of the necessary

materials that compose the object (or project) being

modeled. This includes thermal and mechanical properties.

Generate Mesh At this point ANSYS understands the makeup of the part.

Now define how the modeled system should be broken

down into finite pieces.

Apply Loads Once the system is fully designed, the last task is to burden

the system with constraints, such as physical loadings or

boundary conditions.

Obtain Solution This is actually a step, because ANSYS needs to understand

within what state (steady state, transient… etc.) the problem

must be solved.

Present the Results After the solution has been obtained, there are many ways

to present ANSYS’ results, choose from many options such

as tables, graphs, and contour plots.

6.2 SPECIFIC CAPABILITIES OF ANSYS

6.2.1STRUCTURAL Structural analysis is probably the most common

application of the finite element method as it implies

bridges and buildings, naval, aeronautical, and mechanical

structures such as ship hulls, aircraft bodies, and machine

housings, as well as mechanical components such as

pistons, machine parts, and tools.

· Static Analysis - Used to determine displacements,

stresses, etc. under static loading conditions. ANSYS can



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compute both linear and nonlinear static analyses.

Nonlinearities can include plasticity, stress stiffening, large

deflection, large strain, hyper elasticity, contact surfaces,

and creep.

· Transient DynamicAnalysis - Used to determine

the response of a structure to arbitrarily time-varying loads.

All nonlinearities mentioned under Static Analysis above

are allowed.

· Buckling Analysis - Used to calculate the buckling

loads and determine the buckling mode shape. Both linear

(eigenvalue) buckling and nonlinear buckling analyses are

possible.

MODAL ANALYSIS A modal analysis is typically used to determine the

vibration characteristics (natural frequencies and mode

shapes) of a structure or a machine component while it is

being designed. It can also serve as a starting point for

another, more detailed, dynamic analysis, such as a

harmonic response or full transient dynamic analysis.

Modal analyses, while being one of the most basic

dynamic analysis types available in ANSYS, can also be

more computationally time consuming than a typical static

analysis. A reduced solver, utilizing automatically or

manually selected master degrees of freedom is used to

drastically reduce the problem size and solution time.

7. STRUCTURAL ANAYLSIS OF HELICAL GEAR

7.1ANAYLSIS OF HELICAL GEAR BY

ALUMINUM ALLOY A360

Material properties:-

Density:- 8.88g/cc

Modulus of elasticity:- 207 GPA

Poisson’s ratio:- 0.31

IMPORTED MODEL FOR ALLUMINIUM ALLOY A360

MESHED MODEL FOR ALLUMINIUM ALLOY

A360

LOADS APPLIED FOR ALLUMINIUM ALLOY

A360

DEFORMATION FOR ALLUMINIUM ALLOY

A360

STRESS MODEL FOR ALLUMINIUM ALLOY

A360

7.2 STRUCTURAL ANALYSIS OF NICKEL

CHROMIUM ALLOY

Material properties

Density :- 8.88 g/cc

Modulus of elasticity :-270 Gpa

Poisons ratio :- 0.31



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Figure 3 IMPORTED MODEL FOR NICKEL

CHROMIUM ALLOY

Figure 4 MESHED MODEL FOR NICKEL

CHROMIUM ALLOY

FOR NICKEL CHROMIUM ALLOY

7.3 STRUCTURAL ANSTRUCTURAL ANALYSIS OF

TITANIUM

Material properties:-

Density:-

Modulus of elasticity:-

Poisonratio:-

DEFORMAION

IMPORTED MODEL FOR TITANIUM ALLOY

STRAIN AND STRESS FOR TITANIUM ALLOY

FATIGUE ANAYLSIS OF HELICAL GEAR

8.1FATIGUE ANALYSIS OF ALUMINUM ALLOY

360

Figure 5 MESHED MODEL FOR FATIGUE

ANALYSIS OF ALUMINIUM ALLOY 360



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LOADS APPLIED FOR FATIGUE ANALYSIS OF

ALUMINIUM ALLOY 360

LIFE SPAN OF FATIGUE ANALYSIS FOR

ALUMINIUM ALLOY 360

SAFETY FAACTOR OF FATIGUE ANALYSIS

FOR ALUMINIUM ALLOY 360

8.2 FATIGUE ANALYSIS OF NICKEL

CHROMIUM ALLOY STEEL

IMPORTED MODEL FOR FATIGUE ANALYSIS

OF NICKEL CHROMIUM ALLOY STEEL

MESHED MODEL FOR FATIGUE ANALYSIS OF

NICKEL CHROMIUM ALLOY STEEL

LIFE FOR FATIGUE ANALYSIS OF NICKEL

CHROMIUM ALLOY STEEL

Safety factor

SAFETY FACTOR FOR FATIGUE ANALYSIS OF

NICKEL CHROMIUM ALLOY STEEL

8.3 FATIGUE ANALYSIS OF TITANIUM

IMPORTED MODEL FOR FATIGUE

ANALYSIS OF TITANIUM

LOADS FOR FATIGUE ANALYSIS OF NICKEL

TITANIUM



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LIFE SPAN FOR FATIGUE ANALYSIS OF

TITANIUM

Figure 6 SAFETY FACTOR FOR FATIGUE

ANALYSIS OF TITANIUM

9. CONCLUSION

Gears almost always produce a change in

torque, creating a mechanical advantage, through

their gear ratio, and thus may be considered a simple

machine. The angled teeth engage more gradually than

do spur gear teeth, causing them to run more smoothly

and quietly With parallel helical gears, each pair of teeth

first make contact at a single point at one side of the gear

wheel; a moving curve of contact then grows gradually

across the tooth face to a maximum then recedes until the

teeth break contact at a single point on the opposite side.

In this project we designed component on catia

v5software . we done here analysis for the gear by

choosing three materials aluminum alloy 360,nickel

chromium alloy and titanium .to find the maximum

stresses we done structural analysis .By taking structural

values we have done fatigue analysis to find life of the

component .

In observing the three material stress value is

occur in nickel chromium alloy is we can use but in

aluminum alloy 360 we observed value and the stress

value is minimum on it. So we can say aluminum is

preferable. In fatigue analysis the three materials values

as near to it, so we can use any of the material to

maintain minimum life and safety factor of the

component

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International Journal of Research ISSN NO:2236-6124ijrpublisher.com/gallery/6-january-2019.pdf · 2019-01-02 · FATIGUE ANALYSIS OF A HELICAL GEAR USED IN MARINE APPLICATIONS ABSTRACT