m6. composite materials m

Question 1

what is the term composite used to describe?

Answer 1

two or more materials combined to form a much stronger structure than the material by itself

Question 2

wat are composite composed of?

Answer 2

a matrix and re reinforcing fibers

Question 3

what state is the matrix and the reinforcing fibbers?

Answer 3

matrix is a liquid
reinforcing fibbers are a solid

Question 4

what is the third component added to the composite?

Answer 4

a core material

Question 5

what are the advantages of composite?

Answer 5

high strength to weight ratio
longer service life
higher corrosion resistance
design flexibility
easily repairable

Question 6

what are the disadvantages of composites?

Answer 6

difficult for inspections
lack of long term design data base
expensive
toxic and hazardous
lack of methodology

Question 7

what are the reinforcing fibers?

Answer 7

fiberglass
aramid
black graphite / carbon fibre
boron
ceramic

Question 8

what is the most widely used composite?

Answer 8

fibereglass

Question 9

how is fibre glass made?

Answer 9

glass heated up until molten then feed it through small holes to create glass filaments

Question 10

what is the advantage of fibreglass?

Answer 10

less expensive
does not conduct electricity

Question 11

what are the 2 most common types of fibreglass?

Answer 11

E glass and S glass

Question 12

what is another name for aramid?

Answer 12

Kevlar

Question 13

what types of aramid are the most communally used?

Answer 13

49 and 29

Question 14

what are the advantages of aramid?

Answer 14

low density
flexible
high tensile strength
non flammable and non fusible
heat resistant
good chemical resistance
high toughness

Question 15

what prevents aramid turning brown?

Answer 15

protection from the environment

Question 16

carbon fibre is very what?

Answer 16

strong and used for its rigid property’s

Question 17

carbon fibre has stronger compressive strength than what?

Answer 17

Kevlar

Question 18

what are the advantages of carbon fibre?

Answer 18

high strength
low density
low fracture resistance
resistance to high temps
good electrical conductivity property’s

Question 19

what are two different materials we use as sandpaper and which one will last longer?

Answer 19

aluminum oxide and silicon carbide
silicon carbide lasts longer

Question 20

how is boron made?

Answer 20

apply small amount of vaporized boron onto tin tungsten or carbon wire

Question 21

what is boron used for?

Answer 21

cracked aluminum parts and panels

Question 22

wat are the advantages of boron?

Answer 22

excellent compressive strength
high tensile strength
high stiffness
very hard wearing

Question 23

when are cermic fibers used?

Answer 23

when high temp application is needed

Question 24

cermic reattains most of its strength and flexibility up to what temperature?

Answer 24

1200 degrease Celsius

Question 25

what is the warp?

Answer 25

along the length of the fabric

Question 26

what is the weft / fill?

Answer 26

perpendicular to the warp fibers

Question 27

what is the salvage edge

Answer 27

tightly woven edge parallel to warp threads prevents unraveling

Question 28

what is the bias?

Answer 28

45 degree angle to warp threads

Question 29

what are the different styles of fabric?

Answer 29

unidirectional bidirectional quai isotropic mats

Question 30

what are unidirectional fibers?

Answer 30

major fiber runs in warp direction

Question 31

what are bidirectional fibres?

Answer 31

fibres run in two or more directions

Question 32

what is quasi isotropic lay up?

Answer 32

carbon fiber piles stacked in 0, -45, 45, 90 or 0, -60, 60

Question 33

what are mats?

Answer 33

chopped fibers that are compressed

Question 33

the orientation of the lay up results in what?

Answer 33

constant strength and stiffness

Question 34

wat are mats used with?

Answer 34

woven or unidirectional layers of fabric

Question 35

where are mats used?

Answer 35

marine industry

Question 36

wat are fibric waves resistant to?

Answer 36

fibre break out delamination damage

Question 37

what are the most common types of plain weaves?

Answer 37

plain twill satin

Question 38

what are the characteristics of a plain weave?

Answer 38

simplest form of weave stable difficult to cover complex shapes high degree of crimp

Question 39

what is the characteristics a twill weave?

Answer 39

provide superior wet out to plain weaves flatter more mechanical properties bc of reduced crimp

Question 40

what are the characteristics of a satin weave?

Answer 40

modified twill weaves with fewer inter sections flat facilitates wetting out good mechanical properties difficult to handle used for repairs

Question 41

wat is the matrix?

Answer 41

bonding material that surrounds the fibers

Question 41

what is an example of an early matrix?

Answer 41

polyester

Question 42

what does a resin matrix consist of?

Answer 42

resin and a hardener

Question 43

what are the two general categories of plastics?

Answer 43

thermosetting thermoplastic

Question 44

what are thermosetting plastics?

Answer 44

use heat or a catalyst to set low melting points can not change from new position

Question 44

what are thermoplastics?

Answer 44

heat up to form desired shape can be reheated to change shape

Question 44

what uses epoxy resins?

Answer 44

most advanced composite materials

Question 45

what are epoxy resins well know for?

Answer 45

good strength and resistance to moisture and chemicals

Question 46

is every type of epoxy suitable for every repair?

Answer 46

no

Question 47

where is information about epoxy resins?

Answer 47

product safety data sheet

Question 48

what are pre pregs?

Answer 48

fabrics that already have the correct amount of resin already saturated into the fabric