Composite Materials (week 8-14) Flashcards
combinations of two or more materials that differ in composition or form but each composite material retain their individual identities
Composite Material
E-Glass is manufactured from?
borosilicate glass
S-Glass is manufactured from?
Magnesia-alumina silicate
Which fibres can undergo very high heat?
Ceramic
Boron has a figment of what element?
Tungsten
The bonding substance or adhesive is called?
Matrix
is the element within the composite that is designed to carry the loads.
Reinforcing Material
The third element of a composite structure is the _____ between the matrix and the reinforcing material.
Interface
5 common types of Reinforcing Material
FIBERGLASS CARBON / GRAPHITE BORON CERAMICS ARAMID
_________ is made of molten glass that has been drawns into a fine strand, the stands are then spun and sewn together to form a cloth
Fiberglass
________ is more commonly known as Kevlar, and is flexible
Aramid
_________ ________ is very high in compressive strength and stiffness, and will produce corrosion when bonded to metals
Carbon Fiber
_________ is mostly found in military applications, is also carcinogenic
Boron
_________ is used in high heat applications, like the hot sections of a turbine engine
Ceramic
_______ fibers are ones in which all of the major fibers run in one direction, and provide maximum strength in only that direction.
Unidirectional
Which Fabrics are made where the major fibres are woven so that they run in 2 directions?
Bi-directional
Fabrics are woven on a large machine called a?
Fabric Loom
are fabrics that consist of chopped fibers that are compressed together. There are many strands oriented in random directions
Mat Fabrics
The purpose of the Matrix
to hold the reinforcing fibers in the desired position.
________ ________ is used more in aircraft, has 2 parts: Resin, Catalyst used for bonding, and is moisture resistant
Epoxy Resin
For basic applications, the most common type of materials that will be used will come from the manufacturer in ___ FORM.
Raw
The inclusion of one thing within another so that the included thing is not apparent.
Encapsulation
are materials where the matrix material is already saturated into the material.
Pre-Impregnated Materials (Pre-Pregs)
Advantages of using pre impregnated materials:
1) Convenience.(The materials contain exactly the right amount of matrix material)
2) Complete encapsulation. (Using pre-impregnated materials assures the user that all of the reinforcing material fibers are totally enclosed by the matrix material.)
3) All of the matrix is evenly distributed within the fabric, so there is no need to disturb the fibers.
4) Big advantage is speed. Time is money, especially in aviation.
Disadvantages and limitations of using pre impregnated materials:
1) Storage. These types of materials have very strict limitations when it comes to storage.
2) Once the time limit is exceeded, the material is considered to be scrap and is not to be used for aircraft construction.
3) these products will have a finite shelf life
4) Cost. These materials by themselves are very expensive
also known as fillers are materials that are added to the matrix to control viscosity and weight, increase the pot life and cured strength and make application of the matrix easier.
Thixotropic agents
When there is a central material that is contained in between two face sheets we have what is called?
Sandwich Constructed Panel
The part that is in the middle is called?
Core Material
is the direction in which the honeycomb can be stretched without the honeycomb being pulled apart.
Ribbon Direction
When two or more layers of different materials are laminated together, you have what is known as a?
hybrid laminate
_____ will assist and accelerate the curing process of the matrix.
Heat
What does pressure do?
will assist with the saturation and encapsulation of the fibers with the matrix material and squeezes out excess resin and removes air pockets that are trapped in the lay-up.
Whatever method is used, it is essential that the _______ be carefully controlled so that there is an even distribution of heat.
Heating
___________ _______ is a process that uses a male and female mold to form the part. The impregnated fabrics, (bulk or pre-preg) are laid into the?
Compression Molding, Female Mold
the most common way that the technician will apply pressure on a composite repair. The use of this technique will provide a very uniform application of pressure over the entire surface of the part. It is very well suited for complex shapes and can accommodate large and small parts
Vacuum Bagging
Heating of vacuum bagged composites is usually accomplished through the use of _____ _____ _____ placed into the vacuum bagging setup.
Electric Heating Pad
another manufacturing process that will produce incredibly strong structures.This process uses a continuous thread of reinforcing fiber that is wound a mandrel in the desired shape of the part.
Filament winding
the most simple ways of manufacturing or repairing composite structures. This process involves the use of bulk materials where the matrix is simply applied to the reinforcing material and left to cure. It does not involve the use of heat or pressure and is a favourite of amateur built aircraft.
Wet Lay ups or Hand lay ups
To deal with the transmission of electricity, manufactures will often weave _________ into the reinforcing materials.
Conductors
Other methods include incorporating thin _____ ___ in the lay-up
Aluminum foil
is a defect on the outer surface skin that does not involve damage of the structural reinforcing fibers.
It may be caused by chipping or scratching during handling, does not affect the strength of the part and is usually repaired for aesthetic reasons.
Cosmetic Defects
may occur if the composite part is struck by a foreign object. The degree of damage may range from slight to quite severe
Impact Damage
The most common reason for impact damage
the careless handling during transportation or storage.
the separation of layers of material in a laminate.
Delamination
The presence of _____ within the fabric or a _______ _____ may also encourage delamination.
Moisture, Lightning Strike
Delamination is also the result of?
Poor Workmanship
can occur in advanced composite structures, just as in metallic ones. Sometimes they can be detected visually, other times they may require more advanced methods of Non-Destructive Inspection. (NDI)
Crack
may occur from impact damage, over-torquing fasteners or as the result of fastener pull through.
Hole Damage
The most widely used method to detect surface defects on aircraft. used to detect cracks, surface irregularities (from an internal flaw), and surface defects such as blistering and delamination.
Visual Inspection
Visual inspection can be made more effective through the use of a?
good light source and through the use of magnification, normally a hand held 10 Power magnifying glass.
Delaminations may be detected visually through the use of a?
Bright Light (may appear as a bubble or an indentation)
is a form of NDI used to detect internal flaws or areas where delamination has occurred. In this test a coin or other similar solid metallic object is used to gently tap on the surface being examined.
Coin Tap Test
This type of inspection is used to detect sub-surface flaws.uses a high frequency sound wave as a means of detecting flaws in the part.
Ultrasonic Inspection
This type of inspection locates flaws by temperature variations at the surface of a damaged part. Heat is applied to the part, then the temperature gradients are measured using an infrared camera or film
Thermography
makes use of high energy particles emitted from a radioactive source or from an X-Ray tube.
Radiography
If the repair is determined to be Specialized Work, then the repair must be carried out by an?
appropriately rated AMO.
Always refer to the _______ ________ instructions when carrying out the repair.
Aircraft Manufacturer
Damage will generally have to be removed from the component in order to carry out a repair. This is done either by?
hand sanding, tool assisted sanding or routing the damaged piece.
To apply pressure to the repair, there are some common methods. What are the different methods?
Shot Bags.
Clecos.
Spring Clamps.
Vacuum bagging
Sequence for Vacuum Bagging (first to last, in order)
- Release Ply or film
- Laminate & Dam
- Perforated Release Film
- Bleeder
- Release Film
- Breather
- Bagging Film