Alternative Materials For Aircraft Wings Engineering Essay

For this study I have chosen to research and happen an alternate stuff for aircraft wings, presently the stuff being on aircraft wings is aluminium metal series 2000, specifically 2024 as this metal consists of approximately 4.5 % Cu, 1.5 % Mg, 0.6 % manganese with hints of other specific elements permitted, and the balance aluminum.[ 1 ]The alternate stuff must be capable of accomplishing all the features of aluminum metal 2024, yet be light in weight and sooner within the cost part of stuffs presently used.

Purposes and aims

The purpose of this study is discuss how alternate stuffs can be produced to fabricate a new igniter aircraft wing. In order to make this the new stuff must be capable of defying high emphasis tonss, be light in weight and sooner low in cost. Besides, fabricating technique must be looked into with regard to machinability of stuff, cost of machines, and mending stuff.

Current stuffs in usage

Aluminium metal 2024

This is used in the air power industry as it has the right belongingss required to run into the demands. The rule debasing component used is Cu. This metal requires solution heat intervention to obtain its best belongingss when the metal has been through the solution heat intervention procedure the mechanical belongingss become similar to and sometimes exceed those of mild steel. To farther increase the mechanical belongingss of aluminum metal 2024, an unreal ripening procedure is used ; this method of intervention increases the output strength. Once the aluminum metal has been made, the belongingss obtained are high strength to burden ratio, every bit good as good weariness opposition. Though this is non wieldable and has mean machinability. Due to hapless corrosion opposition the metal is normally cladded with pure aluminum, nevertheless, this does normally cut down the weariness opposition of the metal.

Aluminium metal 2024 consists of approximately 4.5 % Cu, 1.5 % Mg, 0.6 % manganese with hints of other specific elements permitted and the balance is aluminium.

Mechanical belongingss of aluminum 2024

The mechanical belongingss of 2024 depend on the pique of the stuff.

2024-0

This signifier of metal has no heat intervention ( annealed ) . It has an ultimate tensile strength of 207-220 MPa more yield strength of 96 MPa. This signifier of metal besides has an elongation factor of 10-25 % .

2024-T3

This signifier of metal has been solution treated and strain hardened with the ultimate tensile strength is between 400-427 MPa and yield strength of 369-276 MPa with an elongation of 10-15 % .

New stuffs to see

Titanium

This metal has a high strength to burden ratio, a comparative denseness of 4.5 which is 60 % heavier than aluminum nevertheless, it is twice every bit strong.

Titanium has first-class corrosion opposition belongingss this is due to the oxide movie which signifiers. Titanium is non usually susceptible to emphasize, weariness, intergranular or voltaic corrosion, seting or localised onslaught. However, under certain fortunes it will fire in air, hence in order to forestall a reaction with O or N it may be treated with chloride gas in order to organize a protective coating of Ti dioxide.

Titanium normal alloying elements include aluminum, Cr, Fe, manganese, Mo and V.

Titanium and its metals are classed in 3 classs:

Alpha ( A ) – Wieldable, tough, strong both hot and cold and immune to oxidation.

Beta ( B ) – Excellent crook ductileness, strong both hot and cold nevertheless vulnerable to taint.

Combined ( C ) – Combination of alpha and beta with comprised public presentation, strong cold and warm but weak when hot, first-class forgability, good bendibility moderate taint opposition. The runing point of Ti is 1668 grades Celsius and has low thermic conductibility and a low carbon monoxide efficient of enlargement. Its high temperature belongingss are nevertheless dissatisfactory. ; the ultimate output strength falls quickly above 425 grades Celsius and atmospheric O and nitrogen absorbent above 540 grades Celsius makes the metal toffee and worthless after a long term exposure. Therefore it is merely utile for short continuances, high temperatures applications where strength is non of import such as air conditioned firewalls.

When working with Ti excess attention must be taken when doing due to its utmost work indurating belongingss. E.g. center boring should be used prior to boring as centre clout this stuff would indurate the metal, doing trouble when boring.

Composite

A composite stuff consists of 2 or more different stuffs whose mechanical belongingss compliment each other although maintain their separate individualities, unlike metal.

The ground the composite stuffs are used on an aircraft and their strength to burden ration and corrosion opposition. Reinforced plastics are much lighter than metals. If the metal portion can be every bit much as 25 times heavier than an tantamount composite portion, nevertheless that composite portion must be as strong and lasting as the original.

Therefore strengthened plastics must hold really good strength, stiffness and impact opposition.

Strength- this is the ability of a stuff to back up a burden without interrupting.

Stiffness- this is the ability of stuff to back up a burden without flexing excessively much.

Impact- this is the ability of a stuff to defy opposition impact without shattering.

The types of complexs to see for this undertaking would be,

Glass reinforced plastic

Aramid fibers

Carbon fibers

Glass Reinforced Fibres ( GRFs )

Glass Reinforced Fibers are presently used on aircraft for radar domes ( the fairings which cover radio detection and ranging aerials and must be crystalline to radio moving ridges ) . The fiberglass is used for support for thermosetting rosins in aircraft applications is available as a fabric in many different weights and weaves as a loose of fiberglass. When combined, the fiber and rosin GRF.

For applications which require the most strength it is necessary to utilize uni-directional glass tape. Whereas woven glass fabric has better determining belongingss and high strength.

There are many types of Glass Reinforced Fibres used, and the chief 1s used in the air powers industry are:

A – Glass- criterion sodium carbonate glass has a high alkaline content which absorbs wet which increases degrading of stuff and corrosion. This leaks to resins impairment. The chief usage for this is for Windowss.

C – Glass- high opposition to corrosive stuff. It is usually produced and used merely as a surface flatness to cut down cost.

D – Glass- with a low di-electric invariable this type of glass is used for radar domes.

E – Glass- with low base content and good rosin adhesion belongingss where used in air conditioning.

Manners of woven cloth

The most common manner used is the field weave where ; the deflection and wraft togss cross alternately. The strength of woven cloths in comprised due to the terrible ‘pre- buckling ‘ already present in the cloth. Fibers normally produce their greatest strength when they are absolutely consecutive. Due to the high frequence of over and under weaving of the togss the strength is reduced ; in field weave. This is where twill weave and satin weave come in as it is high fictile and stronger than the field weave manner.

2

In satin weave, 1 pennant narration floats over between 3 and 7 warp togss before go throughing under another deflection yarn.

3

Twill weaves offer a via media between satin and field weaves

4

Property

Plain

Twill

Satin

Good Stability

****

***

**

Good Curtain

**

***

*****

Low Porosity

***

****

*****

Smoothness

**

***

*****

Balance

****

****

**

Symmetrical

*****

***

*

Low Crimp

**

***

*****

This tabular array shows a comparing of the belongingss of common weaves used in aerospace:

Stability – ability of the weave to keep together when cut.

Drape – ability of the fabric to follow a complex form.

Porosity – an indicant of the sum of rosin required to thoroughly wet the fabric.

Smoothness – surface coating of the fabric.

Balance – a comparing between the deflection and weft way.

Symmetry – the weave form.

Crimp – an indicant of the sum or frequence of crook in the narrations.[ 5 ]

Aramid cloths

Aramid fibers besides known as ‘Kevlar ‘ is made from aromatic polymeric amide, a type plastic similar to nylon.

The belongingss include ;

High tensile strength and opposition to impact of any composite reinforcing fiber.

Stiffer than glass but merely half every bit stiff as C fiber.

40 % lighter than glass fiber

10x stronger than aluminum

Up to 400 % stronger than comparable glass reinforced laminates.

Up to 20 % stronger than comparable C enforced laminates

Aramid fibers have really high impact strength with the harm confined to little countries. Due to this, Aramid can be used in countries prone to lapidate and runaway debris harm, so this could be utile for usage on aircraft wings.

However, Aramid fibers have lower compaction strength than C, it absorbs wet more readily than glass or C, besides Aramid deteriorates in strong sunshine. Aramid is more hard to cut, bore, sand so either glass or C, it besides does non give clean borders.

Aramid fibers do non defy fire good and burn through more rapidly than other fibers. Resin adhesion is besides lower, delamination being one of the ways in which it absorbs impact energy.

Carbon fibers

Carbon fibers are made from C and are black in color C fibers were foremost used on air conditioning in the 1980 ‘s.

The fibers are industries by the controlled warming of POLYCRILONITRILE ( PAN ) , polyethylene or rayon fibers are pre-oxidised at 200-300 grades Celsius for 1 hr so carbonised at 1200 grades the graphitised at 2000 to 3000 grades Celsius. This removes the H, N and O go forthing long oriented C ironss.

The fibers are sometimes surface oxidized, this improves their edifice features and sized, this so reduces the physique up of inactive electricity and improves adhering.

Carbon fibers are available in signifiers basic groups and produced at different graphitisation temperature and defined by tensile faculties

Standard faculties ( high strength )

Intermediate faculties ( high stiffness )

High modulus

Ultra high modulus.

All signifiers of C fiber are stiffer than glass fibers, nevertheless merely standard modulus is stronger than glass fibers in tenseness. The higher modulus fibers are really brickle and are non suited for general aeronautical usage.

Aluminium- Li

This is portion of series 8000 of aluminum metals. Having low denseness, the Li reduces the weight of metal while offering strength which is comparable to series 7000 ( besides a higher strength aluminum metal made from Zn ) and competes with composite stuffs. Aluminium Li besides has high specific modulus and first-class weariness and cryogenic stamina belongingss.

The disadvantages of aluminum Li is reduces ductileness and break stamina in short transverse way besides the demand to cold work this metal to obtain peak belongingss and speed up fatigue cleft extension rates when clefts are micro structural little.

By utilizing aluminium Li in aircraft wings will enable low costs winging as it saves weight and fuel ingestion costs, besides this would take to a decrease in care costs.

Fatigue affects stuffs after long term exposure to cyclic lading utilizing aluminium Li is stronger than C fiber hence aluminium Li can defy fatigue longer. Aluminium Li is presently being used on the Airbus A380, and under probe with Boeing.

Analysis

Current stuff

The current stuff used for aircraft wings is aluminium. This stuff is presently used to build aircraft wings. This is because this stuff is light in weight, easy to machine, easy to determine besides this signifier of aluminum is easy to machine in order to run into needed criterions such as high output strength in ratio with the weight, and besides aluminum 2024 besides has really good weariness opposition. However, this signifier of aluminium metal has hapless corrosion opposition hence in order to protect against this the metal is cladded with pure aluminum, this nevertheless has a downside to it as it farther reduces the weariness opposition of the metal.

The advantages of aluminum are:

Light weight

Easily shaped/cast/forge

Good electrical music director

Good thermal music director

Easy to machine

The disadvantages of aluminum are:

Expensive to polish ( must be done by electrolysis of amalgamate salts )

Poor chemical opposition ( acids and base )

Loses strengths when heated

Cladded with 6.25mm of pure aluminum, if that is broken, the stuff begins to eat fast.

Alternate stuffs

The alternate stuffs that can be used are:

Titanium

This metal has a high strength to burden ratio, a comparative denseness of 4.5 which is 60 % heavier than aluminum nevertheless it is twice every bit strong.

Titanium has first-class corrosion opposition belongingss this is due to the oxide movie which signifiers. Titanium is non usually susceptible to emphasize, weariness, intergranular or voltaic corrosion, seting or localised onslaught. However, under certain fortunes it will fire in air, hence in order to forestall a reaction with O or N it may be treated with chloride gas in order to organize a protective coating of Ti dioxide.

Titanium and its metals are classed in 3 classs:

Alpha ( A ) – Wieldable, tough, strong both hot and cold and immune to oxidation.

Beta ( B ) – Excellent crook ductileness, strong both hot and cold nevertheless vulnerable to taint.

Combined ( C ) – Combination of alpha and beta with comprised public presentation, strong cold and warm but weak when hot, first-class forgability, good bendibility moderate taint opposition. The runing point of Ti is 1668 grades Celsius and has low thermic conductibility and a low carbon monoxide efficient of enlargement. Its high temperature belongingss are nevertheless dissatisfactory. ; the ultimate output strength falls quickly above 425 grades Celsius and atmospheric O and nitrogen absorbent above 540 grades Celsius makes the metal toffee and worthless after a long term exposure.

The ideal type of Ti to utilize on an aircraft wing would be the combined ( C ) category as it does run into to demands for an aircraft wings. However, the major drawback for this stuff is when working with Ti excess attention must be taken when doing due to its utmost work indurating belongingss.

The advantages of Ti are:

Lightweight

Strong

Able to defy high temperatures

Corrosion resistant

The disadvantages of Ti are:

Expensive

Procedure for organizing and fall ining Ti are complex and expensive

Glass Reinforced Fibres

The fiberglass is used for support for thermosetting rosins in aircraft applications is available as a fabric in many different weights and weaves as a loose of fiberglass. When combined, the fiber and rosin Glass Reinforced Fibre.

For applications which require the most strength it is necessary to se uni-directional glass tape. Whereas woven glass fabric has better determining belongingss and high strength.

There are many types of Glass Reinforced Fibres used, and the chief 1s used in the air powers industry are:

A – Glass- criterion sodium carbonate glass has a high alkaline content which absorbs wet which increases degrading of the stuff and corrosion. This leaks to resins impairment. The chief usage for this is for Windowss.

C – Glass- high opposition to caustic stuffs. It is usually produced and used merely as a surface flatness to cut down cost.

D – Glass- with a low di-electric invariable this type of glass is used for radar domes.

E – Glass- with low base content and good rosin adhesion belongingss.

Manners of woven cloth

The most common manner used is the field weave where ; the deflection and wraft togss cross alternately. The strength of woven cloths in comprised due to the terrible ‘pre- buckling ‘ already present in the cloth. Fibers normally produce their greatest and strength when they are absolutely consecutive. Due to the high frequence of over and under weaving of the togss the strength in reduced in field weave. This is where twill weave and satin weave come in as it is high fictile and stronger than the field weave manner.

The advantages of GRF are:

Strength and opposition can be adjusted during the fabrication

Impact opposition

Lightweight

Heat resistant

Will non eat

Able to defy all but the strongest signifiers of acid and base

The disadvantages of GRF are

Easy to damage

Expensive machines required to bring forth

Requires particular storage

Although glass reinforced fibers are really good with regard to the advantages and disadvantages, it may non be the ideal pick to utilize as a stuff for an aircraft wing as it would be expensive to bring forth and hive away, and besides there are many types of glass reinforced fibers but non a peculiar type could be chosen because there is non a stuff which is specifically ideal and has all the features required for an aircraft wing.

Aramid

Aramid fibers have really high impact strength with the harm confined to little countries. Due to this, Aramid can be used in countries prone to lapidate and runaway debris harm, so this could be utile for usage on aircraft wings.

However, Aramid fibers have lower compaction strength than C, it absorbs wet more readily than glass or C, besides Aramid deteriorates in strong sunshine. Aramid is more hard to cut, bore or sand so either glass or C ; it besides does non give clean borders.

The advantages of Aramid are:

High tensile strength

Impact resistant

Ten times every bit strong as aluminum

400 % stronger than GRF

20 % stronger than C fiber

The disadvantages of Aramid are:

Low compressive strength so C

Absorbs wet more than glass or C fiber

Deteriorates in sunshine

Difficult To Cut, Drill or Sand

Does non give clean cut borders

Aramid is a really good stuff to utilize, nevertheless it is of import that when doing aircraft skin the wings must be smooth and easy to machine, due to Aramid non being able to supply these cardinal characteristics, it should be used for this portion of the tegument, nevertheless, Aramid should be considered for the taking border of the aircraft wings, because it has the features required to defy rock and runaway debris harm.

Aluminium- Lithium

Having low denseness, the Li reduces the weight of metal while offering strength which is comparable to series 7000 ( besides a higher strength aluminum metal made from Zn ) and competes with composite stuffs. Aluminium Li besides has high specific modulus and first-class weariness and cryogenic stamina belongingss.

The disadvantages of aluminum Li is reduces ductileness and break stamina in short transverse way besides the demand to cold work this s metal to obtain peak belongingss and speed up fatigue cleft extension rates when clefts are micro structural little.

Fatigue affects stuffs after long term exposure to cyclic lading utilizing aluminium Li is stronger than C fiber hence aluminium Li can defy fatigue longer.

The advantages of aluminium-lithium are:

10 % denser than aluminum 2024

Lightweight

10 – 15 % higher modulus than aluminum 2024

Excellent weariness and cryogenic stamina belongingss

Higher stiffness

Superior weariness cleft growing opposition

The disadvantages of aluminium-lithium are:

Reduced ductileness

Low break stamina

Aluminium- Li is a new construct within the air power industry which allows the industry to come on in a new way, this allows an aircraft to be light, efficient yet have the same sum of or more power to transport both riders and cargo. Besides, with aircraft being so light it may let even bigger aircrafts so the presently produced Airbus A380, and Boeing 787 to be produced. Aluminium- Li the features required for usage on aircraft wings and therefore should be considered for this undertaking.

Decision

In decision aluminium- Li should be used as it has the belongingss such as light weight and first-class weariness and cryogenic stamina belongingss required for an aircraft wing and carry the weight loaded on to the plane hence enabling aircrafts to be designed on a bigger graduated table in order to transport more lading and riders as is proven by the production of the Airbus A380 which is one the largest planes in production giving a higher power to burden ratio.

The A380 ‘s wing is sized for a maximal take-off weight ( MTOW ) over 560A metric tons in order to suit these future versions, albeit with some strengthening required. The stronger wing ( and construction ) will be used on the A380-800F bottom. This common design attack sacrifices some fuel efficiency on the A380-800 rider theoretical account, but Airbus estimates that the size of the aircraft, coupled with the progresss in engineering will supply lower operating costs per rider than the 747-400 and older 747 discrepancies.[ 6 ]

Mention

Books Used ;

British Airways Engineering Training Part 66 Module 6- Materials and Hardware. Published: 14/02/2005. Issue: 1.

Introduction to aircraft design. John P. Fielding. ISBN: 0521657229

Aircraft Design Projects: For Engineering Students. Lloyd R. Jenkinson. Dr. Jim Marchman. ISBN: 0750657723

Web sites used:

hypertext transfer protocol: //www.sciencedaily.com/releases/2007/09/070926094727.htm

hypertext transfer protocol: //en.wikipedia.org/wiki/Al-Li

www.soton.ac.uk/~jps7/ … /manufacturing/aluminum-lithium.doc

www.keytometals.com/Article58.ht

hypertext transfer protocol: //en.wikipedia.org/wiki/Airbus_A380 # cite_note-norris_wagner_book-12

Appendix 1