final for adhesive in 10.11.12

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ABSTARCT

Due to the extreme costs associated with delivering cargo into space, there is a strong

demand from the space industry to increase the load capacity of the carriers. To keep the total

weight of the system unchanged, an increase in load capacity must be accompanied by a decrease

in the structural weight of the carrier. Just as within the aerospace and to some extent the

automotive industry, the use of lightweight composite material to replace earlier all metal

constructions have accelerated. There are still inevitably components that have to be made of

metal and the interface between the different materials can then become an engineering

challenge.

Our project is to design the turbine exhaust duct (TED) of aerospace engine in a

composite material in order to reduce the weight. Naturally this TED operates under very

demanding conditions with cryogenic temperatures, high internal pressure, external structural

loads and a pure hydrogen environment and the present TED is a robustly designed in cast

Inconel 718, a nickel-based super alloy which is relatively heavy weight of about 7.7 kg when

compared to other aerospace engine components. The flanges that form the interface with

surrounding engine parts will still need to have a metal contact surface against the other

components in order to assure a tight high pressure seal. For this reason a metal composite

hybrid design is proposed where metal flanges are attached to a composite tubular body. The

component geometry and the demand for a smooth inner surface leave adhesives as the only

feasible option for the joints.

This project investigates about the behavior of adhesively bonded joints when it is

subjected to combined structural and thermal loadings between the turbine exhaust duct (TED)

and attached titanium flanges, which is foremost priority before going for composite hybrid

design. And also deals with the possibility of designing the Turbine Exhaust Duct (TED) of the

aeronautical engine in composite materials like carbon fiber reinforced plastics (CFRP), E-Glass/Epoxy, and Boron/Epoxy which leads to the reduction of weight of TED. The design

model of TED is to be generated by using Pro/E Wildfire 5.0 and analyzed report is to be

generated by using ANSYS 11.0 for the existing load condition during the engine run cycle.


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CHAPTER: 1

INTRODUCTION:

1.1 THE TURBINE EXHAUST DUCT :( TED)

A larger total thrust can be obtained from the engine if the gases are discharged from the

aircraft at a higher velocity than is permissible at the turbine outlet. An exhaust duct is therefore

added, both to collect and straighten the gas flow as it comes from the turbine and to increase the

velocity of the gases before they are discharged from the exhaust nozzle at the rear of the duct.

Increasing the velocity of the gases increases their momentum and increase the thrust produced.

For the aerospace engines, the turbine exhaust duct is used for the liquid oxygen (LOX)

and liquid hydrogen (LH2) fuel supply pump systems. In the Hydrogen Turbo-Pump (TPH), high

pressure gaseous hydrogen (GH2) provides the power through a turbine connected to the pump

drive shaft. After passing the turbine, the GH2 is passed through the Turbine Exhaust Duct

(TED) in which it is divided into a main flow to power the Oxygen Turbo-Pump (TPO) and a

secondary by-pass that can be passed on directly to the combustion chamber. The TED operates

under very demanding conditions with cryogenic temperatures, high internal pressure, external

structural loads and a pure hydrogen environment. Typically during an engine run cycle, the

temperature inside the TED varies between room temperature and -140C and the internalpressures reaches as high as 10 MPa. Naturally this is very stressing on the component material

and the present TED is a robustly designed in cast Inconel 718, a nickel-based super alloy.

Sample LH2 turbine data:

Number of stages 1 Nominal speed 91,000 rpm (max 102,000) Nominal power output 2500 kW (max 3700 kW) Mean gas diameter 120 mm Mass flow 4.9 kg/s Turbine inlet pressure 180 Bar (max 232 Bar) Turbine inlet temperature 245 K (Max 325 K) Pressure ratio 2:1


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Fig no: 1.1 turbine exhaust duct.

1.2 COMPOSITE DETAILS:

Composite materials are engineered materials made from two or more constituentmaterials that remain separate and distinct while forming a single component

Generally, one material forms a continuous matrix while the other provides thereinforcement

The two materials must be chemically inert with respect to each other so no interactionoccurs upon heating until one of the components melts, an exception to this condition is asmall degree of inter diffusion at the reinforcement-matrix interface to increase bonding

Composites can be found in:

The aerospace industry (structural components as well as engines and motors) Automotive parts (panels, frames, dashboards, body repairs) Sinks, bathtubs, hot tubs, swimming pools Cement buildings, bridges Surfboards, snowboards, skis Golf clubs, fishing poles, hockey sticks Trees are technically composite materials, plywood Electrical boxes, circuit boards, contacts everywhere.


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Why Composites are Important?

Composites can be very strong and stiff, yet very light in weight, so ratios of strength-to-weight and stiffness-to-weight are several times greater than steel or aluminum.

Fatigue properties are generally better than for common engineering metals. Toughness is often greater too. Composites can be designed that do not corrode like steel. Possible to achieve combinations of properties not attainable with metals, ceramics, or

polymers alone.

1.3 CLASSIFICATION OF COMPOSITE:

Composites can be classified by their matrix material which includes:

Metal matrix composites (MMCs) Ceramic matrix composites (CMCs) Polymer matrix composites (PMCs) or sometimes referred to as organic matrix

composites (OMCs)


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MMC - Metal Matrix Composites

The matrix is relatively soft and flexible. The reinforcement must have high strength and stiffness. Since the load must be transferred from the matrix to the reinforcement, the

reinforcement-matrix bond must be strong.

MMC use:

Two types of particulates (dispersion strengthened alloys and regular particulatecomposites) or long fiber reinforcements.

PMC - Polymer Matrix Composites:

The matrix is relatively soft and flexible The reinforcement must have high strength and stiffness Since the load must be transferred from matrix to reinforcement, the reinforcement-

matrix bond must be strong

CMCCeramic Matrix Composites:

The matrix is relatively hard and brittle. The reinforcement must have high tensile strength to arrest crack growth. The reinforcement must be free to pull out as a crack extends, so the reinforcement-

matrix bond must be relatively weak.


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Table: 1.1 types of composites:

1.4 COSTS OF COMPOSITE MANUFACTURE:

Material costs -- higher for composites

Constituent materials (e.g., fibers and resin) Processing costs -- embedding fibers in matrix Not required for metals Carbon fibers order of magnitude higher than aluminum Design costs -- lower for composites Can reduce the number of parts in a complex assembly by designing the material in

combination with the structure

Increased performance must justify higher material costs.


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1.5 Types of Composite Materials:

There are five basic types of composite materials:

1. Fiber.2. Particle.3. Flake.4. Laminar or layered.5. Filled composites.

Fig no: 1.2 types of composite materials

(1) Fiber Composites:

In fiber composites, the fibers reinforce along the line of their length. Reinforcement may

be mainly 1-D, 2-D or 3-D. Figure shows the three basic types of fiber orientation.

1-D gives maximum strength in one direction. 2-D gives strength in two directions. Isotropic gives strength equally in all directions.


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Fig no: 1.3 basic types of fiber orientation.

(2) Particle Composites:

Particles usually reinforce a composite equally in all directions (called isotropic).Plastics, cermets and metals are examples of particles.

Particles used to strengthen a matrix do not do so in the same way as fibers. For onething, particles are not directional like fibers. Spread at random throughout a matrix,

particles tend to reinforce in all directions equally.

Cermets:

(1) OxideBased cermets:

(E.g. Combination of Al2O3 with Cr)

(2) CarbideBased Cermets:

(E.g. Tungstencarbide, titaniumcarbide)

(3)Metalplastic particle composites:

(E.g. Aluminum, iron & steel, copper particles)

(4)Metalinmetal Particle Composites and Dispersion Hardened Alloys:

(E.g. Ceramicoxide particles)


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3. a.Flake Composites1

Flakes, because of their shape, usually reinforce in 2-D. Two common flake materials areglass and mica. (Also aluminum is used as metal flakes)

Fig no :1.4 Flake Composites.

b.Flake Composites -2

A flake composite consists of thin, flat flakes held together by a binder or placed in amatrix. Almost all flake composite matrixes are plastic resins. The most important flake

materials are:

1. Aluminum2. Mica3. Glassc.Flake Composites -3

Basically, flakes will provide:

Uniform mechanical properties in the plane of the flakes Higher strength Higher flexural modulus Higher dielectric strength and heat resistance Better resistance to penetration by liquids and vapor Lower cost


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4.a.Laminar Composites1:

Laminar composites involve two or more layers of the same or different materials. The

layers can be arranged in different directions to give strength where needed. Speedboat hulls are

among the very many products of this kind.

b.Laminar Composites2:

Like all composites laminar composites aim at combining constituents to produceproperties that neither constituent alone would have.

In laminar composites outer metal is not called a matrix but a face. The inner metal, evenif stronger, is not called reinforcement. It is called a base.

c.Laminar Composites3:

We can divide laminar composites into three basic types:

Unreinforcedlayer composites(1) AllMetal

(a) Plated and coated metals (electro galvanized steelsteel plated with zinc)

(b) Clad metals (aluminumclad, copperclad)

(c) Multilayer metal laminates (tungsten, beryllium)

(2) MetalNonmetal (metal with plastic, rubber, etc.)

(3) Nonmetal (glassplastic laminates, etc.)

a. Reinforcedlayer composites (lamina and laminates)

b. Combined composites (reinforcedplastic laminates well bonded with steel, aluminum,

copper, rubber, gold, etc.)


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d.Laminar Composites4:

A lamina (laminae) is any arrangement of unidirectional or woven fibers in a matrix.Usually this arrangement is flat, although it may be curved, as in a shell.

A laminate is a stack of lamina arranged with their main reinforcement in at least twodifferent directions.

Fig no :1.5 Laminar Composites.

5.Filled Composites:

There are two types of filled composites. In one, filler materials are added to a normalcomposite result in strengthening the composite and reducing weight. The second type of

filled composite consists of a skeletal 3-D matrix holding a second material. The most

widely used composites of this kind are sandwich structures and honeycombs.

Combined Composites:

It is possible to combine several different materials into a single composite. It is alsopossible to combine several different composites into a single product. A good example is

a modern ski. (combination of wood as natural fiber, and layers as laminar composites)

Fig no: 1.6 Combined Composites.


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1.6 Forms of Reinforcement Phase:

Fibers cross-section can be circular, square or hexagonal Diameters --> 0.0001 - 0.005 Lengths --> L/D ratio

100 -- for chopped fiber much longer for continuous fiber

Particulate small particles that impede dislocation movement (in metal composites) and

strengthens the matrix

For sizes > 1 mm, strength of particle is involves in load sharing with matrix Flakes

flat platelet formFiber Reinforcement:

The typical composite consists of a matrix holding reinforcing materials. The reinforcingmaterials, the most important is the fibers, supply the basic strength of the composite.

However, reinforcing materials can contribute much more than strength. They can

conduct heat or resist chemical corrosion. They can resist or conduct electricity. They

may be chosen for their stiffness (modulus of elasticity) or for many other properties.

1.7 Types of Fibers:

The fibers are divided into two main groups:

Glass fibers: There are many different kinds of glass, ranging from ordinary bottleglass to high purity quartz glass. All of these glasses can be made into fibers. Each

offers its own set of properties.

Advanced fibers: These materials offer high strength and high stiffness at lowweight. Boron, silicon, carbide and graphite fibers are in this category. So are the

aramids, a group of plastic fibers of the polyamide (nylon) family.


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FibersGlass:

Fiberglass properties vary somewhat according to the type of glass used. However, glass

in general has several wellknown properties that contribute to its great usefulness as a

reinforcing agent:

Tensile strength Chemical resistance Moisture resistance Thermal properties Electrical properties

There are four main types of glass used in fiberglass:

Aglass Cglass Eglass Sglass

Most widely used fiber

Uses: Piping, tanks, boats, sporting goods

Advantages:

Corrosion resistance Low cost relative to other composites, Low cost

Disadvantages:

Relatively low strength High elongation Moderate strength and weight

Types:

E-Glass - electrical, cheaper S-Glass - high strength


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Fibers - Aramid (Kevlar, Twaron):

Uses:

High performance replacement for glass fiberExamples:

Armor, protective clothing, industrial, sporting goodsAdvantages:

Higher strength and lighter than glass More ductile than carbon

FibersCarbon:

2nd most widely used fiberExamples:

aerospace, sporting goodsAdvantages:

high stiffness and strength Low density Intermediate cost

Properties:

Standard modulus: 207-240 Gpa Intermediate modulus: 240-340 GPa High modulus: 340-960 GPa Diameter: 5-8 microns, smaller than human hair Fibers grouped into tows or yarns of 2-12k fibers


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Fibers -- Carbon (2):

Types of carbon fiber:

vary in strength with processing Trade-off between strength and modulus

Intermediate modulus:

PAN (Polyacrylonitrile)Fiber precursor heated and stretched to align structure and remove non-carbon material

High modulus:

made from petroleum pitch precursor at lower cost much lower strength

FibersOthers:

Boron High stiffness, very high cost Large diameter - 200 microns Good compressive strength

Polyethylene - trade name: Spectra fiber Textile industry High strength Extremely light weight Low range of temperature usage

Fibers -- Others (2)

Ceramic Fibers (and matrices)

Very high temperature applications (e.g. engine components) Silicon carbide fiber - in whisker form. Ceramic matrix so temperature resistance is not compromised Infrequent use


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Fiber Material Properties

Fig no: 1.2 material properties of typical fibers.


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CHAPTER-2

2.1 ADHESIVE INTRODUCTION:

There is an apparent growth of joining metals to composites, especially in the

aeronautics. The reasons are the attractive mechanical properties (high strength, high stiffness,

resistance to the propagation of structural damage) of both materials and also the reduction of

costs. Because composites are almost always used for their superior mechanical properties, the

need for joints that can sustain high loads and stresses is extremely important.

Organic/polymeric, metallic, inter metallic, ceramic, and carbon types of composites all pose

different problems. One must always keep in mind the compatibility of chemical, physical and

mechanical properties of all materials involved in joints.

There are generally three options for joining metals to composites:

(1) Mechanical Fastening,

(2) Adhesive bonding and

(3) rivet-bonding.

2.2 General description of Adhesive Bonding:

Adhesive bonding is the process of joining materials with the aid of a substance, acting asa chemical agent, capable of holding those materials together by surface attachment forces. The

materials being joined are called the adherend, while the bonding agent is called the adhesive.

The forces that enable the surface attachment arise from one or more of several fundamental

sources, most of which are chemical in origin, but some of which can be mechanical or even

electrostatic. The adhesive bonding is fundamentally a chemical bonding process. Adhesives

transmit stresses from one element of a joint (or one adherend) to another in such a way that the

stresses are distributed more uniformly than in most mechanical method and welds.


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2.3 Theories for Adhesive Bonding:

Four theories explain the process of adhesive bonding by explaining the underlying Phenomena

leading to adhesion:

1) The electrostatic theory of adhesion (based on electrostatic forces between adherend and

adhesive)

2) The diffusion theory of adhesion (based on partial solubility of adherend and Adhesive)

3) The mechanical theory of adhesion (based on adhesives penetration into the Microscopic

asperities of adherend, resulting in mechanical interlocking.)

4) The adsorption theory of adhesion.

Fig no: 2.1 structure of adhesive bonding.

2.4 Types of Adhesives

Lists the various forms of adhesive bonding

1. Natural Adhesives:

Animal-based adhesives (e.g. casein, collagen, gelatin, lac) Plant-based adhesives (e.g. pitch, natural rubbers, asphalt) Mineral-based adhesives (e.g. sodium silicate, water glass, mineral-based sol-gels,

calcium carbonate)

2. Synthetic Adhesives:

Synthetic Organic Adhesives Chemically-activated adhesives (e.g. anaerobic, cyanoacrylates, epoxies)


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In many applications adhesively bonded joints are more suitable than traditional joining

techniques such as mechanical fastening, especially for components made from composite or

polymeric materials, because they can provide uniform distribution of load, resulting in better

damage tolerance and excellent fatigue life. Whereas adhesively bonded joints and bonded

repairs made to cracked metallic Structures have been continuously receiving attention in the

aerospace industry for the purpose of enhancing fatigue resistance and restoring the stiffness and

strength of damaged/cracked structures, the effective use of adhesive bonding technology in

primary structural members is still in its infancy. Because of the involvements of many

geometric, material and fabrication variables, and complex failure modes And mechanics

presented in the joints, a deep understanding of the failure behavior of adhesively bonded joints,

particularly under combined loading conditions, is needed in order to fully achieve the benefits

of adhesive bonding. There are several Typical failure modes associated with adherends and

adhesive in adhesively bonded composite repairs including substrate yielding; patch fiber

breaking in tension, fiber failing in compression, adhesive shearing, substrate-adhesive peeling,

patch-adhesive peeling, patch inter laminar peeling, and patch inter laminar shearing. Since

substrate yield is not a catastrophic failure mode, an optimal design will focus on other failure

modes associated with the patch and adhesive.

The failures in adhesively bonded joints are mainly of two types, adhesive and cohesive;

occurring mainly due to interfacial (adhesive) cracking, also called deboning, at geometric

boundaries due to stress concentrations, or resulting from faulty joining in fabrication. Well-

bonded joints should fail within the adhesive (cohesive) or within the adherends (inter laminar

failure) when broken apart. Failure at the adherend-adhesive interface (interfacial failure)

generally indicates that the bond was not performed properly. Stress based concepts provide a

realistic description of the stresses and strains and information on the physical cause for material

rupture.

In order to explain the mechanical behaviors of adhesively bonded joints and develop a

failure prediction method it is useful to be able to predict the stresses acting in the joint. Nominal

adhesive peel and shear stresses are related to mode-I and mode-II deformation of the adhesive

layer, respectively. Stress-based approaches, which focus on indicating both shear and normal

(peel) stresses through standard lap shear tests, have been the subject of a vast amount of


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researches. Adhesive bonding usually requires curing of adhesive at temperature higher than

applied condition. When two adherend have dissimilar material properties and subsequently

having mismatch coefficients of thermal expansions, the curing process create residual stress in

jointed materials, such situations generally are produced when one adherend is made of

composite material and another is metallic material. Composite patch commonly used in

aerospace industry particularly in cracked metallic structures, are subjected to thermal loading

due to difference in the operating temperature of the aircraft in flight time or bonding process

due to curing of the adhesive. Accurate computational thermal stress analysis is particularly

important for estimation of the service life of bonded joints and repairs. In this study, a finite

element thermal stress analysis was conducted in order to investigate the behavior of adhesively

bonded joints using double-lap joints.

1. Major classes of adhesive:

Adhesives can be classified by several methods, none of them perfect, such as the way

they set (that is, transform from a wetting liquid to a load-bearing solid), the way they are used in

assembly, or by chemical type. The strongest adhesives set by chemical reaction. Less strong

types harden by physical change, cooling from a melt or evaporation of a solvent. The major

classes are described below.

2. Anaerobic:

Anaerobic adhesives cure when in contact with metal, and the air is excluded For

Example, when a bolt is home in a thread. They are often known as 'locking compounds', being

used to secure, seal and retain turned, threaded, or similarly close fitting parts. They are based on

synthetic acrylic resins.

3. Cyanoacrylates:

Cyanoacrylate adhesives cure through reaction with moisture held on the surface to be

bonded. They need close fitting joints and usually solidify in seconds. Cyanoacrylates are suited

to small plastic parts and to rubber. They are a special type of acrylic resin.


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4. Toughened Acrylics:Toughened acrylics are fast curing and offer high strength and toughness. Both one-part

and two-part systems are available. In some two-part systems, no mixing is required because the

adhesive is applied to one substrate, the activator to the second substrate, and the substrates

joined. They tolerate minimal surface preparation and bond well to a wide range of materials.

5. Epoxies:

Epoxy adhesives consist of an epoxy resin plus a hardener. They allow great versatility in

formulation since there are many resins and many different hardeners. Epoxy adhesives can be

used to join most materials. Epoxies have good strength, do not produce volatiles during curing

and have low shrinkage. However, they can have low peel strength and flexibility and are brittle.

Epoxies adhesives are available in one-part, two-part and film form and produce extremely

strong durable bonds with most materials.

6. Polyurethanes:

Polyurethane adhesives are chemically reactive formulations which may be one-part or

two-part systems and are usually fast curing. They provide strong impact-resistant joints and

have better low-temperature strength than any other adhesive. Polyurethanes are useful for

bonding glass fiber reinforced plastics (GRP). The fast cure usually necessitates applying the

adhesives by machine. They are often used with primers.

7. Silicones:

Silicones are not very strong adhesives but are known for their flexibility and high

Temperature resistance. They are available in single or two-part forms. The latter Function like

the two-part epoxies, the former like the single-part polyurethanes. When the single-part

adhesives cure they liberate either alcohol or acetic acid (the familiar smell of vinegar).They is

often used as bath and shower sealants. Their adhesion to surfaces is only fair but, like their

flexibility, their durability is excellent. The two-part versions need a hardening agent to be mixed

into the resin. Two forms are available - those which liberate acid on curing and those that do

not. As might be anticipated, the two-part adhesive systems give a better cure in thick sections

than do the single-part types.


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8. Phenolics:

Phenolics were the first adhesives for metals and have a long history of successful use for

joining metal to metal and metal to wood. They require heat and pressure for the curing process.

9. Polyamides:

Polyamides are mainly used in applications which exploit their ability to withstand

Temperature up to 350C. They are available as liquids or films and although they have good

strength retention at high temperature, they have the disadvantage of being expensive and

difficult to handle. The following adhesives undergo a physical change and are less effective at

forming an adhesive bond.

10. Hot-melts:

Hot-melts are based on modern thermoplastics and are used for fast assembly of

Structures designed to be only lightly loaded.

11. Plastisols:

Plastisols are modified PVC dispersions which require heat to harden. The resultant joints

are often resilient and tough.

12. Rubber Adhesives:

Rubber adhesives are based on solutions of latexes and solidify through loss of the

Solvent medium. They are not suitable for sustained loadings.

13. Polyvinyl acetate (PVAs):

Vinyl acetate is the principal constituent of the PVA emulsion adhesive. They are suited

to bonding porous materials, such as paper or wood, and to general packaging work.

14. Pressure-sensitive adhesives:

Pressure-sensitive adhesives are suitable for use as tapes and labels and, although they do

not solidify, are often able to withstand adverse environments. This type of adhesive is not

suitable for sustained loadings.


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15. Adhesive selection principles:

Selection of an adhesive for a particular application may at first appear daunting.

However, there are many sources of assistance, such as adhesive suppliers, expert Consultants

and computer-based selection systems. Since none of these sources can be comprehensive, there

are some guiding principles which will help in any decision-making process. The joint type, joint

function, in-service conditions and manufacturing issues must all be considered. But by defining

a few key performances or manufacturing requirements, this will quickly deselect most potential

adhesive types.


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CHAPTER-3

3.1 PROBLEM DEFNITION:

The TED operates under very demanding conditions with cryogenic temperatures, high

internal pressure, external structural loads and a pure hydrogen environment. Typically during an

engine run cycle, the temperature inside the TED varies between room temperature and -140C

and the internal pressures reaches as high as 10 MPa. Naturally this is very stressing on the

component material which causes deformation of adhesive joint between TED and Titanium

Flange. And the present TED is a robustly designed in cast Inconel 718, a nickel-based super

alloy which is relatively heavy weight of about 7.7 kg when compared to other aerospace

engine components.

3.2 EXISTING MATERIAL PROPERTIES:

FOR DUCT:

INCONEL alloy 718 (UNS N07718/W.Nr. 2.4668) is a high-strength, corrosion-resistant

nickel chromium material used at -423 to 1300F. Typical composition limits are shown in

Table 1. The age-harden able alloy can be readily fabricated, even into complex parts. Its

welding characteristics, especially its resistance to post weld cracking, are outstanding. The ease

and economy with which INCONEL alloy 718 can be fabricated, combined with good tensile,

fatigue, creep, and rupture strength, have resulted in its use in a wide range of applications.

Examples of these are components for liquid fueled rockets, rings, casings and various formed

sheet metal parts for aircraft and land-based gas turbine engines, and cryogenic tankage. It is also

used for fasteners and instrumentation parts.

3.3 Inconel 718Nickel-Chromium Alloy in (TED):

Inconel 718 is a Nickel-Chromium alloy being precipitation hardenable and having high

creep-rupture strength at high temperatures to about 700C (1290F). It has higher strength than

Inconel X-750 and better mechanical properties at lower temperatures than Nimonic 90 and

Inconel X-750
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Chemical Composition of Inconel 718: The compositional range forInconel 718 is provided in

the table1.2 below.

Table:3.1Chemical Composition of Inconel 718:

Element Content

Ni+Co 50 - 55 %

Cr 17 - 21 %

Fe BAL

Nb+Ta 4.75 - 5.5 %

Mo 2.8 - 3.3 %

Ti 0.65 - 1.15 %

Al 0.2 - 0.8 %

Typical Properties of Inconel 718:

Table:3.2 Typical properties ofInconel 718 are covered as follows:

Property Metric Imperial

Density 8.19 g/cm 0.296 lb/in

Melting point 1336 C 2437 F

Co-Efficient of thermal

Expansion13.0m/m.(20-100C)

7.2x10 in/in.F

(70-212 F)Modulus of rigidity 77.2 KN/mm 11197 ksi

Modulus of elasticity 204.9 KN/mm 29719 ksi

Relevant Standards:

Inconel 718 is covered by the following standards:

AMS 5663

AMS 5832

AMS 5962

AMS 5662

ASTM B637
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Applications of Inconel 718:

Inconel 718 typically finds application in:

Gas turbines

Rocket motors

Space craft

Nuclear reactors and pumps.

3.4 ABOUT TITANIUM FLANGE:

ATI Ti-6Al-4V, Grade 5 Titanium Alloy (UNS R56400)

INTRODUCTION:

ATI Ti-6Al-4V, Grade 5 alloy (UNS R56400) is the most widely used titanium grade. It is a

two phase + titanium alloy, with aluminum as the alpha stabilizer and vanadium as the beta

stabilizer. This high-strength alloy can be used at cryogenic temperatures to about 800F

(427C). ATI Ti-6Al-4V, Grade 5 alloy is used in the annealed condition and in the solution

treated and aged condition. Some applications include: compressor blades, discs, and rings for jet

engines; airframe and space capsule components; pressure vessels; rocket engine cases;helicopter rotor hubs; fasteners; critical forgings requiring high strength-to-weight ratios.

Grade 5, also known as Ti6Al4V, Ti-6Al-4V orTi 6-4, is the most commonly used alloy. It

has a chemical composition of 6% aluminum, 4% vanadium, 0.25% (maximum) iron, 0.2%

(maximum) oxygen, and the remainder titanium.[5]

It is significantly stronger than

commercially pure titanium while having the same stiffness and thermal properties

(excluding thermal conductivity, which is about 60% lower in Grade 5 Ti than in CP Ti) .[6]

Among its many advantages, it is heat treatable. This grade is an excellent combination of

strength, corrosion resistance, and weld and fabric ability
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Technical information - mechanical properties of titanium:

Table: 3.3: mechanical properties of titanium:

ALLOY

Yield

Strength

(0.2%)

(Ksi)

TensileStrength

(Ksi)

Elongation

(%)

Reduction inArea

(%)

Hardness

Grade5

(6AL-4V)120 130 10 20 28-34Rc

3.5 ADHESIVE JOINT:

Traditionally in engineering, structural joining has been synonymous to riveting, bolting

and other purely mechanical fastening together with welding or soldering in the case of metallic

construction materials. Up until the introduction of the polymeric adhesives around the time of

the Second World War these were the only means of joining available but with the increased use

of plastics, and more importantly fiber reinforced composite materials, the use of adhesive

joining has increased rapidly and is today found in numerous applications with different material

configurations. The reason for the increased use of adhesive joining is that it can provide a

number of structural and economical advantages over more traditional methods of joining, of

course assuming that the joint is properly designed. One of the most important features to keep inmind during the initial joint design is that adhesive joints are very strong in shear, but

unfortunately are very vulnerable to normal stresses (in the context of adhesives commonly

referred to as peel stresses). Provided that the joint is loaded in its favorable direction, some of

the advantages are

High strength to weight ratio Stresses distributed evenly over the joint width No drilled holes needed Weight and material cost savings Improved aerodynamic surface design Superior fatigue resistance Outstanding electrical and thermal insulation


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As with any other technology, there are also limitations to consider when using adhesives in

engineering. Elevated temperatures and high humidity can result in negative effects on the

strength of some types of adhesives, especially when under continuous stress, and as with other

polymeric materials, creep effects must be considered. Even though manufacturing procedures

such as drilling, machining and riveting can be avoided when using adhesive fastening, this is

replaced with a need for careful surface preparation prior to bonding, especially when using

metal adherends. When designing an adhesively bonded structure, one of the first questions that

arise is the cross-sectional geometry of the joint. Figure shows a comprehensive overview of the

most commonly used engineering adhesive joints and the terminology of the various adherend

shapes.

Fig no: 3.1 Overview of a loaded SLJ with and without an adhesive spew fillet. Areas sensitive

to crack initiation are marked in red.

3.6 ADHESIVE PROPERTIES:

Table: 3.4:EA9394 properties units& values:

S.NO properties units Value

1. Youngs modules n/mm2

4.071e3

2. Poisson ratio - 0.37

3. Thermal conductivity w/m.k 0.331

4.Co-efficient of thermal

expansionm/c 55.6


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3.7 PROPOSED ALTERNATIVE MATERIAL FOR TED:

DUCT MATERIAL:

Here the proposed material is changed for only the duct design alone and the material is

listed as follows:

Three composites used are:

Boron / Epoxy E Glass Polyester Resin Carbon/epoxy

Table: 3.5: turbine exhausts duct material (TED) properties & values:

S. no Property units Boron /EpoxyE-glass

Polyester

resin

Carbon

epoxy

1

Young's

Modulus X

directionpa 281.86e9 3.4e10

1.34e11

2

Young's

Modulus Y

directionpa 10.88e9 6.53e9

3

Youngs

Modulus Zdirection

pa 10.88e9 6.3e9

4

Major

Poisson's

Ratio XY

- 0.2451 0.217 0.3

5Shear

Modulus XYpa 67.49 2.433e9 -

6 Density Kg/m3 2249 2100 1600


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3.8 OBJECTIVE OF THE PROJECT:

The objective of the project is to analyze the adhesive joint itself to identify the critical

stress in parts for the existing load cases and also to reduce the weight by using composite

material. Here the duct is to be designed and analyzed by applying various material properties

such as cast INCONEL 718 and composites materials like carbon fiber reinforced plastics, Glass

Epoxy, Boron epoxy, and also adhesive bond structure between TED and Flange is to be

designed as a thin layer and it is analyses by applying various adhesive properties.

3.9 METHODOLOGY:

The duct and flange is to be designed as the 3d modeling by using Pro/E Wildfire 5.0.withrespect to their existing design specimen.

The adhesive joint is created as thin layer in 3d modeling. Than the duct, flange and titanium is to be assembled. The assembled TED is converted into as a single part model through IGES format

conversion.

The FEA is done to be for imported IGES modeling by using ANSYS. The material properties value is applied for the meshed model after the report is generated.

final for adhesive in 10.11.12

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