AMCR COMPOSITES Flashcards
is a material composed of solid materials of carry-load that
are contained in a material much weaker.
Composite Material
is often referred to as the stronger material and the weaker
material is usually referred to as the matrix.
Reinforcement
The reinforcement provides the requisite ____________ that helps to
sustain the structural load.
Strength and Stiffness
5 Types of Fiber
Fiber Glass, Kevlar, Carbon / Graphite, Boron, Ceramic
Types of Fiberglass
Electrical glass or E-glass, S-glass, S2-glass
is identified as such for electrical applications. It has
high resistance to current flow and is made from borosilicate glass.
Electrical glass or E-glass
identify structural fiberglass that have a higher strength
than E-glass and is produced from magnesia-alumina-silicate.
S-glass and S2-glass
Advantages of fiberglass
○ lower cost than other
composite materials,
○ chemical or galvanic
corrosion resistance, and
○ electrical properties
(fiberglass does not conduct
electricity).
has a white color and is available as a dry fiber
fabric or prepreg material.
Fiberglass
are light weight, strong,
and tough.
Aramid fibers
DuPont’s name for aramid fibers.
Kevlar®
Two types of Aramid fiber are used in the aviation industry.
Kevlar® 49, Kevlar® 29
A Kevlar that has a high stiffness
Kevlar 49
A Kevlar that has a low stiffness
Kevlar 29
An advantage of aramid fibers is their
high resistance to impact damage
The main disadvantage of aramid
fibers is their general
weakness in compression and hygroscopy
are very stiff and strong, 3 to 10 times stiffer than
glass fibers. It is used for structural aircraft applications, such as floor beams,
stabilizers, flight controls, and primary fuselage and wing structure.
Carbon and Graphite Fibers
Advantages of Carbon and Graphite Fibers
high strength and corrosion resistance.
Disadvantages of Carbon and Graphite Fibers
lower conductivity than aluminum
are very stiff and have a high tensile and compressive strength. The fibers
have a relatively large diameter and do not flex well. Also. these are used to repair
cracked aluminum aircraft skins, because the thermal expansion of this is close
to aluminum and there is no galvanic corrosion potential.
Boron
are used for high-temperature applications, such as turbine
blades in a gas turbine engine.
Ceramic Fibers
The ceramic fibers can be used to temperatures up
to?
2,200 °F
Types of Matrix
Metal Matrix Composites, Ceramic Matrix Composites, Polymer Matrix Composites
are composed of a metallic matrix
(aluminum, magnesium, iron, cobalt, copper) and a dispersed ceramic (oxides,
carbides) or metallic (lead, tungsten, molybdenum) phase.
Metal Matrix Composites (MMC)
are composed of a ceramic matrix and
embedded fibers of other ceramic material (dispersed phase).
Ceramic Matrix Composites (CMC)
are composed of a matrix from thermoset
(Unsaturated Polyester (UP), Epoxy (EP)) or thermoplastic (Polycarbonate
(PC),Polyvinylchloride, Nylon, Polysterene) and embedded glass, carbon, steel
or Kevlar fibers (dispersed phase).
Polymer Matrix Composites (PMC)
a generic term used to designate the polymer.
Resin
Types of Resin
Thermoset, Thermoplastic
are the most diverse and widely used of all man-made
materials. They are easily poured or formed into any shape, are compatible with
most other materials, and cure readily (by heat or catalyst) into an insoluble solid.
These resins are also excellent adhesives and bonding agents.
Thermosetting Resin
can be softened repeatedly by an increase of temperature
and hardened by a decrease in temperature. Processing speed is the primary
advantage of thermoplastic materials. Chemical curing of the material does not
take place during processing, and the material can be shaped by molding or
extrusion when it is soft.
Thermoplastic Resins
Types of Thermosetting Resins
Polyester, Vinyl Ester, Phenolic, Epoxy, Polyimides, Polybenzimidazoles, Bismaleimides
are relatively inexpensive, fast processing resins used
generally for low cost applications. Low smoke producing ___________ are
used for interior parts of the aircraft.
Polyester Resin
is the same as those of conventional polyester resins in
terms of appearance, handling properties, and curing characteristics of _______. However, the corrosion resistance and mechanical properties of
_________ composites are much improved over standard polyester resin
composites.
Vinyl Ester Resin
are used for interior components because of their low smoke
and flammability characteristics.
Phenolic Resin
are polymerizable thermosetting resins and are available in a variety of
viscosities from liquid to solid. These are used widely in resins for prepreg
materials and structural adhesives.
Epoxy
excel in high-temperature environments where their thermal
resistance, oxidative stability, low coefficient of thermal expansion, and solvent
resistance benefit the design. Their primary uses are circuit boards and hot
engine and airframe structures.
Polyimides
is extremely high temperature resistant and is used
for high temperature materials.
Polybenzimidazoles
have a higher temperature capability and higher
toughness than epoxy resins, and they provide excellent performance at
ambient and elevated temperatures. Also, these are suitable for standard
autoclave processing, injection molding, resin transfer molding, and sheet
molded compound (SMC) among others.
Bismaleimides
Types of Thermoplastic Resins
Semicrystalline, Amorphous, Polyether Ether Ketone
possess properties of inherent flame
resistance, superior toughness, good mechanical properties at elevated
temperatures and after impact, and low moisture absorption. They are used in
secondary and primary aircraft structures.
Semicrystalline Thermoplastics
are available in several physical forms, including
films, filaments, and powders. Combined with reinforcing fibers, they are also
available in injection molding compounds, compressive moldable random
sheets, unidirectional tapes, woven prepregs, etc.
Amorphous Thermoplastics
a high temperature thermoplastic. This
aromatic ketone material offers outstanding thermal and combustion
characteristics and resistance to a wide range of solvents and proprietary fluids.
Polyether Ether Ketone (PEEK)
Curing Stages of Resin
A, B, C
The components of the resin (base material and hardener) have been mixed
but the chemical reaction has not started. The resin is in the ____ during a wet layup
procedure.
A Stage
The components of the resin have been mixed and the chemical reaction
has started. The material has thickened and is tacky. The resins of prepreg materials
are in the ______.
B Stage
The resin is fully cured. Some resins cure at room temperature and others
need an elevated temperature cure cycle to fully cure.
C Stage
3 Types of Adhesives
Film, Paste, Foaming
are available using high temperature aromatic amine or catalytic curing agents with a wide range of flexibilizing and toughening agents.
Film Adhesives
are used as an alternative to film adhesive. These are often used
to secondary bond repair patches to damaged parts and also used in places where
film adhesive is difficult to apply.
Paste Adhesives
are about 0.025-inch to 0.10-inch thick sheets of B staged
epoxy.
Foaming Adhesives
12 Core Materials
Honeycomb
Kraft Paper
Thermoplastics
Aluminum
Steel
Specialty Metals
Aramid Paper
Fiberglass
Carbon
Ceramics
Foam
Balsa Wood
The most common core material used for aircraft ________
structures is aramid paper (Nomex® or Korex®). Fiberglass is used for higher
strength applications.
Honeycomb
Relatively low strength, good insulating properties, is available in
large quantities, and has a low cost.
Kraft Paper
Good insulating properties, good energy absorption and/or
redirection, smooth cell walls, moisture and chemical resistance, are
environmentally compatible, aesthetically pleasing, and have a relatively low cost.
Thermoplastic
best strength-to-weight ratio and energy absorption, has good heat
transfer properties, electromagnetic shielding properties, has smooth, thin cell
walls, is machinable, and has a relatively low cost.
Aluminum
Good heat transfer properties, electromagnetic shielding properties, and
heat resistant.
Steel
Relatively high strength-to- weight ratio, good heat
transfer properties, chemical resistance, and heat resistant to very high
temperatures.
Specialty Metals (Titanium)
Flame resistant, fire retardant, good insulating properties, low
dielectric properties, and good formability.
Aramid Paper
Tailorable shear properties by layup, low dielectric properties, good
insulating properties, and good formability.
Fiberglass
Good dimensional stability and retention, high-temperature property
retention, high stiffness, very low coefficient of thermal expansion, tailorable
thermal conductivity, relatively high shear modulus, and very expensive.
Carbon
Heat resistant to very high temperatures, good insulating properties, is
available in very small cell sizes, and very expensive.
Ceramics
used on homebuilts and lighter aircraft to give strength and
shape to wing tips, flight controls, fuselage sections, wings, and wing ribs. These are not commonly used on commercial type aircraft. These are typically
heavier than honeycomb and not as strong.
Foam Core
a natural wood product with elongated closed cells; it is
available in a variety of grades that correlate to the structural, cosmetic, and
physical characteristics.
Balsa Wood
Properties of a Core Material
High Strength to Weight Ratio
Lightweight
Fire Resistant
Chemical & Weathering Resistant
Color
Translucency
Design Flexibility
Low Thermal Conductivity
Manufacturing Economy
Fiber composites are extremely
strong for their weight. By refining
the laminate many characteristics
can be enhanced.
High Strength-to-Weight Ratio
A standard Fiberglass laminate has a
specific gravity in the region of 1.5,
compared to Alloy of 2.7 or steel of
7.8.
Lightweight
The ability for composites to
withstand fire has been steadily
improving over the years.
Fire Resistant
resist the attack of a wide range of
chemicals. Because of this, they are
used in the manufacture of chemical
storage tanks, pipes, chimneys and
ducts, boat hulls and vehicle bodies.
Chemical & Weathering Resistant
Most are naturally pigmented. Costs
are therefore reduced by no further
finishing or painting. Dark colors are
not recommended which absorbs
excessive heat.
Color
Polyester resins are widely used to
manufacture translucent mouldings
and sheets. Light transmission of up
to 85% can be achieved.
Translucency
Because of the versatility of
composites, product design is only
limited by your imagination.
Design Flexibility
seems to be most competitive or superior to a composite based design in
an aircraft.
Aluminum Lithium alloy material
Aerospace Aluminum Alloys
2014 - Medium strength
2024 - Damage tolerant
2090 - High Strength aluminum lithium alloy
2195 - wieldable, Al-Li Alloy; low temp
2219 - Weld able; low & elevated temp
2618 - elevated temp
6013 - Corrosion Resistant
7010,7050,7055 - High Strength
7075 - High Strength, tough
8009, 8019 - Elevated Temp
8090 - Damage tolerant of Al-Li alloy
Comparison of Al-Li Alloy with Composites
● Al-Li alloys are more cost-effective, have higher damage tolerance,
and easier manufacturing processes than composites.
● Al-Li alloys are fully recyclable, while composites are practically
non-recyclable.
Nano-Technology Applications
● Nanotechnology enhances
structures, modifies
surfaces, and provides new
sensor and manufacturing
technologies.
● Advanced aircraft materials
find applications in the
automotive industry for
enhanced durability and
cost-effectiveness.
Isotropic vs Anastropic
Isotropic material - uniform strength in all directions
Anastropic material – strength in limited number of
directions
