materials and their applications

MATERIALS DESIGN AND MATERIALS DESIGN AND ENGINEERINGENGINEERING

Semester II, 2008-09

Indian Institute of Information Technology, Design & Manufacturing Jabalpur

MATERIALS IN MATERIALS IN AIRCRAFT AIRCRAFT

APPLICATIONSAPPLICATIONS

Materials in Aircraft Applications


Basic Design of an Aircraft Gas Turbine Engine

Combustion Chamber

TurbineExhaust Gases

Inlet Air

Inlet Air

Compressor

Exhaust Nozzle

Key Components of a Turbojet Gas

Turbine Engine are • A Compressor• A Combustion Chamber• A Turbine

Other elements of the design are An Exhaust Nozzle, A Mixer (which is usually placed between

the turbines and the exhaust nozzleAn After-Burner


Rotating Compressor Blades

Stationary Compressor Blades

Basic Design Features of the Compressor Section

The ambient air is drawn into the compressor and gets pressurized as it is redirected between one set of stators and rotating blades. Thus the compressor pulls air into the engine, raises its temperature and pressure and delivers it to the combustion chamber.


STATIONARY TURBINE BLADES

ROTATING TURBINE BLADES MOUNTED ON THE

SHAFT

COMBUSTIONCHAMBER

Basic Design Features of the Combustion Chamber

and the Turbine

The compressed high-pressure air is thoroughly mixed with a fine spray of fuel in the combustion chamber and the mixture is ignited. The hot exhaust combustion gases expand rapidly and pass at high speed through the turbine section, which again is an array of rotating blades and stators, and are rejected to the atmosphere through the exhaust nozzle.

Materials in Aircraft Applications The Carnot Cycle

consists of two adiabatic (no gain or loss of heat) and two isothermal processes.

For a cyclic heat engine process, the PV diagram will be closed-loop, the area inside the loop representing the amount of work done during the cycle.

Not all the heat supplied in the heat enginecan be used to do work.

It is clear that the efficiency of the heat engine can be increased by increasing TH TH – Temperature of Isothermal Expansion,

TC – Temperature of Gas Compression


The relationship between altitude of cruising and the Mach number of aircraft speed


Ramjet EnginesRamjet Engines

Unlike conventional turbojet engines, a ramjet engine provides thrust for an aircraft using no moving part (compressor or turbine).

At supersonic speeds the air compresses itself by ramming into a barrier. Therefore, instead of using a compressor to increase the air pressure, a ramjet compresses the air using the speed of the aircraft itself.

Even though a ramjet compresses the air entering at supersonic speeds, the air moving through the engine itself must be slowed to subsonic speed to enable efficient combustion. The compressed air is therefore slowed down. It subsequently enters the combustion chamber and exits through the nozzle after burning.


Scramjet EnginesScramjet Engines

The term scramjet stands for supersonic combustion ramjet.

Scramjet engines work much the same way as ramjets but burn hydrogen instead of hydrocarbon fuel.

The hydrogen is stored in the craft as an extremely cold liquid. The liquid hydrogen cools the engine. In the process it is warmed enough to become a gas, which serves as the fuel. The difference between a ramjet and a scramjet is that the fuel in scramjet is combusted while the air is at supersonic speeds and therefore does not require to be slowed down.

Materials in Aircraft Applications THE FUSELAGETHE FUSELAGE

The fuselage, in essence, is the body of the airplane and holds all the pieces together.

The fuselage, along with the passengers and cargo, contribute a significant portion of the weight of an aircraft. The center of gravity of the aircraft is the average location of the weight and it is usually located inside the fuselage.

In flight, the aircraft rotates around the center of gravity because of torques generated by the elevator, rudder, and ailerons. The fuselage must be designed with enough strength to withstand these torques.


History of Materials Usage in

AircraftsImportant Landmarks

1903 Wright Brothers

1912 Hans Reissner

1940s

1950s

1960s

1970s

1980s

1990s

Wood, Metallic wires, Fabric (Glider Materials)

First all-metal monoplane, wings made from Al

Al alloy airframe, Turbine Blades from Fe-35Ni-15Cr-2Ti Steel/ Nimonic 80 (Ni-20Cr-2.5Ti)

Increased use of Superalloys for engine components, beginning of Ti alloys for frame

Development of advanced superalloys, beginning of (+ ) Ti alloys for engine parts

FRP Composites for Airframe Applications

Single Crystals and DS superalloys for blades

Intermetallics, Ceramics, Advanced Composites

Wood Monocoque

Steel or AlFraming

A Stresses Skin, Al-Li Alloys, Superplastic Forming/DB

Mg Sheet Casting

High Strength Steel Forgings

SS & Superalloys, PM-HIP, SPF/DB

Titanium Skins & Forgings, SPF/DB

B-EP

Gr-EP, Gr-PI, Gr-TP

MMC, Whisker REG

C/CC, CMC

1920 1940 1960 1980 2000 2020


Wood, Wire, Fabric


Elastic Modulus (Yong’s, Shear and Bulk)

Strength (Yield, Tensile and Fracture)

Hardness

Toughness

Fracture Toughness

Damping Capacity

Fatigue Endurance Limit

Creep Resistance

Stress Rupture Strength

Design-Limiting Properties of

Materials

MECHANICAL PROPERTIES


Thermal Conductivity

Thermal Diffusivity

Specific Heat

Melting Point

Thermal Expansion Coefficient

Thermal Shock Resistance

Glass Transition Temperature


Materials

THERMAL PROPERTIES



Materials

WEAR Archard’s Wear Constant

CORROSION Corrosion Rate

OXIDATION Oxidation Rate

DENSITY

COST

Manufacturing in Si Age

Microchips are made of large number of small transistors (circuit elements).

Historically circuits are measured in microns

1 micron – 1/1000 of 1 mm

Approximately 70 times smaller than the width of a human hair

Today’s advanced technologies are measured in terms of nanometers

1 nanometer = 1/1000 of a micrometer

That is thousands of times smaller than the width of a human hair

Chip Design and Scale of its magnitudeChip Design and Scale of its magnitude

Inside the ChipInside the Chip

The inside of the chip consists of various kinds of thin films and layers which need to be deposited/ created on the silicon wafer substrate.

Manufacturing of a micro/nano chip goes in sequential steps.

Part of the Process Flow chart is shown here

Manufacturing Steps for Manufacturing Steps for Mico/Nano Chip MakingMico/Nano Chip Making

Manufacturing Steps Manufacturing Steps for Mico/Nano Chip for Mico/Nano Chip

MakingMaking

BONE IMPLANTSBONE IMPLANTS

How Materials Engineers Affect How Materials Engineers Affect Technological Developments in the Technological Developments in the

Field of Bio-MaterialsField of Bio-Materials

ES 103: II Semester, 2007-08ES 103: II Semester, 2007-08 Instructor Incharge: Dr S BhargavaInstructor Incharge: Dr S Bhargava

The bones of the skeleton perform several The bones of the skeleton perform several functions:functions:

• Provide supportProvide support

• Provide protection of internal Provide protection of internal organs from mechanical damage (e.g., organs from mechanical damage (e.g., skull, ribs)skull, ribs)

• Serve as reservoir of calcium and Serve as reservoir of calcium and phosphatephosphate

• Since all types of blood cells Since all types of blood cells are are produced in the bone marrow (some 10produced in the bone marrow (some 101111 of them each day in an adult human), of them each day in an adult human), bones also serve as the source of blood bones also serve as the source of blood cells. cells.

Functions of Bones in Functions of Bones in Human BodyHuman Body

The hip is aThe hip is a ball and socketball and socket joint.joint. It It comprises of two main parts:comprises of two main parts:

The FemurThe Femur andand The PelvisThe Pelvis

The femur is the thighbone and forms a ball The femur is the thighbone and forms a ball at its tip.at its tip.

The socket, a part of the pelvis, is called the The socket, a part of the pelvis, is called the acetabulum.acetabulum.

The joint operates with the femoral ball The joint operates with the femoral ball fitting into the acetabulum. fitting into the acetabulum.

A smooth layer of A smooth layer of cartilagecartilage and a thin layer of and a thin layer of synovial fluidsynovial fluid (lubricant) form (lubricant) form between the ball and socket and ensure that bones are able to move in a nearly between the ball and socket and ensure that bones are able to move in a nearly frictionless environment.frictionless environment.

HOW DOES A HIP JOINT HOW DOES A HIP JOINT FUNCTION?FUNCTION?

• The most common cause of the hip joint The most common cause of the hip joint failure isfailure is osteoarthritisosteoarthritis..

• Osteoarthritis occurs in middle-aged or Osteoarthritis occurs in middle-aged or elderly individuals when the cartilage and elderly individuals when the cartilage and synovial fluid in the hip joint gradually synovial fluid in the hip joint gradually dissipate due to wear and tear over an dissipate due to wear and tear over an extensive period of time. extensive period of time.

• This causes the underlying bone to become This causes the underlying bone to become exposed. exposed.

Pain results as the femoral ball and the acetabulum rub directly against each Pain results as the femoral ball and the acetabulum rub directly against each other.other.

FAILURE OF THE HIP JOINTFAILURE OF THE HIP JOINT

A common cause of hip pain is A common cause of hip pain is inflammationinflammation of the joints. of the joints.

Inflammation increases pressure within the joint, damaging the cartilage Inflammation increases pressure within the joint, damaging the cartilage lining of the hip. This can be caused by a variety of conditions:lining of the hip. This can be caused by a variety of conditions:

Rheumatoid arthritisRheumatoid arthritis is the general inflammation of joints. is the general inflammation of joints.

Avascular necrosis is often the result of alcohol abuse. It decreases the Avascular necrosis is often the result of alcohol abuse. It decreases the blood supply to the hip, which causes the bone around the joint to die from blood supply to the hip, which causes the bone around the joint to die from lack of nourishment. lack of nourishment.

Other causes of hip malfunction are trauma to the joint and dislocation of Other causes of hip malfunction are trauma to the joint and dislocation of the femoral ball from the acetabulum cup.the femoral ball from the acetabulum cup.

OTHER REASONS OF HIP OTHER REASONS OF HIP JOINT FAILUREJOINT FAILURE

• Surgery begins with the removal of the Surgery begins with the removal of the deteriorated femoral head. deteriorated femoral head.

HIP ANTHROPLASTY: HIP HIP ANTHROPLASTY: HIP REPLACEMENT SURGERYREPLACEMENT SURGERY

In an injured hip, the In an injured hip, the primary damage primary damage exists on the upper exists on the upper femoral ball, femoral ball,

The ball is The ball is dislocated from dislocated from the acetabulum the acetabulum and then and then removed by removed by cutting through cutting through the femoral the femoral neck, neck,

The femoral canal is The femoral canal is then prepared so that a then prepared so that a prosthetic femoral prosthetic femoral stem can replace the stem can replace the removed portion of the removed portion of the femurfemur

The core of the The core of the mostly hollow mostly hollow femur is cleaned femur is cleaned and enlarged in the and enlarged in the shape of the shape of the implant stemimplant stem

Acetabulum Acetabulum is also is also prepared by prepared by cleaning and cleaning and enlarging enlarging with circular with circular reamers of reamers of gradually gradually increasing increasing sizesize

HIP ANTHROPLASTYHIP ANTHROPLASTY

The plastic inner The plastic inner portion of the portion of the implant is placed implant is placed within the metal within the metal shell and fixed into shell and fixed into place.place.

The new femoral The new femoral stem is then insertedstem is then inserted

The new acetabular shell The new acetabular shell is implanted securely is implanted securely within the prepared within the prepared hemispherical socket.hemispherical socket.

THE HIP THE HIP ANTHROPLASTY ANTHROPLASTY IS DONEIS DONE

HIP ANTHROPLASTYHIP ANTHROPLASTY

HOW DOES IMPLANT LOOK AFTER HOW DOES IMPLANT LOOK AFTER THE SURGERY IS DONE?THE SURGERY IS DONE?

DESIGN OF HIP IMPLANTSDESIGN OF HIP IMPLANTS

THE IMPLANT COMPRISES OF THREE PARTSTHE IMPLANT COMPRISES OF THREE PARTS

Femoral BallFemoral Ball Femoral StemFemoral Stem

Acetabular Acetabular SocketSocket

HIP IMPLANT DESIGNSHIP IMPLANT DESIGNS

Both, STEM as well as BALL, Both, STEM as well as BALL, can be parts of a single piece can be parts of a single piece

implantimplant

STEM and BALL can be STEM and BALL can be manufactured from two different manufactured from two different materials and can then be joined materials and can then be joined togethertogether

In addition, the design of the HIP implant may In addition, the design of the HIP implant may be based on the three different following be based on the three different following approaches for joining:approaches for joining:

CEMENTED IMPLANTSCEMENTED IMPLANTS

CEMENTLESS IMPLANTSCEMENTLESS IMPLANTS

HYBRID IMPLANTSHYBRID IMPLANTS

HIP IMPLANT DESIGNSHIP IMPLANT DESIGNS

CEMENTED HIP CEMENTED HIP IMPLANTSIMPLANTS

When a bonding material is used When a bonding material is used to coat the implant stem before to coat the implant stem before placing into the hollow femoral placing into the hollow femoral canal, thecanal, the implant is known as the implant is known as the CEMENTED IMPLANT.CEMENTED IMPLANT.

Cemented fixing relies on a stable Cemented fixing relies on a stable interface between the prosthesis interface between the prosthesis and the cement, on one hand, and and the cement, on one hand, and a solid mechanical bond between a solid mechanical bond between the cement and the bone on the the cement and the bone on the other.other.

Unless the material for cementing Unless the material for cementing is chosen carefully, the cement is chosen carefully, the cement may loosen and fail with time.may loosen and fail with time.

LOOSENING OF CEMENTED HIP LOOSENING OF CEMENTED HIP IMPLANTSIMPLANTS

•In patients In patients who are very active or very heavy,who are very active or very heavy, ccracks (fatigue fractures) can result in the racks (fatigue fractures) can result in the cement over extended period of usage.These cement over extended period of usage.These cracks can loosen the prosthetic stem which, cracks can loosen the prosthetic stem which, in turn, becomes unstable. in turn, becomes unstable.

The friction of the ball against the acetabular socket The friction of the ball against the acetabular socket creates wear debris. The generated wear debris creates wear debris. The generated wear debris particles can then trigger a biological response that particles can then trigger a biological response that further contributes to loosening of the implant and further contributes to loosening of the implant and sometime to loss of bone around the implant. sometime to loss of bone around the implant.

CONTRIBUTION OF MECHANICAL PROCESSES:CONTRIBUTION OF MECHANICAL PROCESSES:

•The microscopic debris particles are absorbed by cells around the joint and initiate an inflammatory response from the body, which tries to remove them.

•This inflammatory response can also cause cells to remove bits of bone around the implant, a condition called OSTEOLYSIS.

•As the bone weakens, the instability increases. Progressing from the edges of the implant, bone loss can occur around both the acetabulum and the femur.

LOOSENING OF CEMENTED LOOSENING OF CEMENTED HIP IMPLANTSHIP IMPLANTS

CONTRIBUTION OF BIOLOGICAL PROCESSES:CONTRIBUTION OF BIOLOGICAL PROCESSES:

CEMENTLESS HIP CEMENTLESS HIP IMPLANTSIMPLANTS

Research has shown that bone will attach to a metal implant if the surface of the metal has a surface topography that is conducive to attracting new bone growth.

Human Cancellous Bone structure containing

interconnected pores (100X)

Porous structure produced on the Stem/Acetabular

surface (100X)

The coarse and gritty exterior of the stem allows the bone to essentially grow into the surface of the implant.

The porous coating, when combined with the surface topography of the stem implant, is conducive to bone growth, allowing it to achieve fixation within the bone.

CEMENTLESS HIP CEMENTLESS HIP IMPLANTSIMPLANTS

An acetabular socket having surface topography that resembles the porous

structure of bone

MMATERIALSATERIALS AND THEIRAND THEIR

SELECTION SELECTION FORFOR PRODUCINGPRODUCING HIP HIP

IMPLANTSIMPLANTS

PROPERTY REQUIREMENTS FROM PROPERTY REQUIREMENTS FROM HIP IMPLANT MATERILASHIP IMPLANT MATERILAS

• They must have They must have mechanical mechanical properties that duplicate the properties that duplicate the structures they are intended to replace; Thus they must be structures they are intended to replace; Thus they must be strong enough to take weight bearing loads, flexible enough to strong enough to take weight bearing loads, flexible enough to bear stress without breaking and able to move smoothly against bear stress without breaking and able to move smoothly against each other as required,each other as required,

• They resist to They resist to corrosioncorrosion, , degradationdegradation and and wear wear whereby they whereby they retain their strength and shape for a long time. Proper joint retain their strength and shape for a long time. Proper joint functioning would otherwise be affected,functioning would otherwise be affected,

• They must be They must be biocompatiblebiocompatible, i.e., they function in the body , i.e., they function in the body without creating either a local or a systemic rejection response,without creating either a local or a systemic rejection response,

• They meet the highest standards of They meet the highest standards of fabricationfabrication and quality and quality control at a control at a reasonable costreasonable cost. .

Rail wheels serve several functions:

(a) They support the bogey weight,

(b) They steer the vehicle through curves,

(c) They also serve as heat sinks during on-tread braking.

The service loading conditions of wheels include those due to wheel-on-rail contact as well as thermal loads from frictional heating during on-tread braking.

RAIL WHEELS

The Loading Pattern

Rail

Wheel Flange

Wheel Rim

Wheel Plate

The loading of the rail as well the wheel is cyclic in nature.

Frictional heating at the point of contact between the rails and the wheel increases the temperature.

Estimates of the surface temperature vary. It is usually suggested that the surface temperature increases to about 400 – 500oC. Detailed microstructural studies of grain sizes and deformation, however, suggest that the temperature goes as high as 1000oC.

Starting cylindrical Steel Block

Wheel Manufacturing by ForgingWheel Manufacturing by Forging

Wheel Blank

Intermediate Wheel Shape

Final Wheel Shape

Post Forging Heat Treatment

Schematic Representation of Three Schematic Representation of Three Rail Wheel DesignsRail Wheel Designs

Plate

Rim

Flange

Hub

Straight Plate S-Plate Freight Wheel

Nuclear EnergyNuclear Energy

Principle of Nuclear Power GenerationPrinciple of Nuclear Power Generation

Heat

Steam produced

Steam

Turbine

Generator

Electricity

Principle of Nuclear Power GenerationPrinciple of Nuclear Power Generation

Boiling Water Reactor (BWR)Boiling Water Reactor (BWR)

Containment Vessel1.5-inch thick steel

Shield Building Wall3 foot thick reinforced concrete

Dry Well Wall5 foot thick reinforced concrete

Bio Shield4 foot thick leaded concrete with1.5-inch thick steel lining inside and out

Reactor Vessel4 to 8 inches thick steel

Reactor Fuel

Weir Wall1.5 foot thick concrete

Reactor DesignReactor Design

Core of the Core of the ReactorReactor

One of the Bundles of the One of the Bundles of the Reactor CoreReactor Core

Nuclear FuelNuclear Fuel

UO2 Pellets

World Uranium ProductionWorld Uranium Production

Market ResearchMarket Research

Market ForecastMarket Forecast

Product ConceptProduct Concept

Process PlanningProcess Planning

Process Selection, Process Design, Process Parameters, Tools & Dies, Quality Control

Process R&DProcess R&D

Process Modeling & Optimization

ProcessingProcessing

Parts Manufacturing, Sensing and Corrective Action Taking; Storing, Moving and Handling

Assembly

Production Production ControlControl

Routing, Scheduling, Production Tracking,

Inventory Control, Purchasing,

Receiving, Quality Assurance

DispatchingDispatching

Customer ServiceCustomer Service

Disposal/RecyclingDisposal/Recycling

COMMON COMMON DATABASE DATABASE FOR CAD FOR CAD AND CAMAND CAMProduct DesignProduct Design

Industrial Design Mechanical Elelctrical Materials Product R&D

Design & Analysis

Production PreparationProduction Preparation Assembly Drawings

Part DrawingsMake/Buy Decisions

materials and their applications

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