week 8

Question 1

what is a composite material

Answer 1

structural material consisting of 2 or more constituent material (however the constituent remain separate)

Question 2

what do composite material provide

Answer 2

they provide properties significantly superior to individual components

Question 3

advantages of using composite materials (5 points)

Answer 3

high strength and stiffness 
fatigue resistant 
corrosion-resistant 
energy absorbant 
fewer parts needed to create a product

Question 4

disadvantages of using composite materials (5 points)

Answer 4

lack of ability to design
difficult to test
expensive
properties depend on manufacturing

Question 5

what 2 things do composites consist of

Answer 5

continuous median and discontinuous median

Question 6

what is a continuous median

Answer 6

this is the matrix

Question 7

what is the discontinuous median

Answer 7

this is known is the reinforcement

Question 8

what is a matrix

Answer 8

this is the composite material like a metal

Question 9

what is a reinforcement

Answer 9

this is the second part of the component like a fibre (carbon and ‘fibre’)

Question 10

what are the 4 main types of material composite

Answer 10

fibre (main one)
particle
laminar
sandwich

Question 11

what does a fibre reinforced composite material contain

Answer 11

made of a matrix with reinforced fibres

Question 12

what is a fibre

Answer 12

a thread, that is significantly longer than its width, categorized by aspect ratio

Question 13

what is the aspect ratio for a short and long fibre

Answer 13

short fibre - 20 to 60 AR

long fibre - 200 to 500 AR

Question 14

What is a composite in carbon fibre

Answer 14

this is the fibre embedded in the matrix

Question 15

what is an anisotropic material

Answer 15

this is when they have different properties in different directions

Question 16

why are fibres used as a discontinuous

Answer 16

because fibres compared to thick material have the same or more strength

Question 17

what is the job of a matrix (2 things)

Answer 17

it partly binds the reinforcement together and keeps the reinforcements correctly positioned

Question 18

what does these stand for:
MMC
CMC
PMC

Answer 18

MMC - metal metal composit
CMC - ceramic matal cimposit
PMC - polymer metal composit

Question 19

what 2 groups do polymeric matrices fall into

Answer 19

thermosets and thermoplastics

Question 20

what is a thermoset

Answer 20

polymer with cross-links and has an irreversible chemical process

Question 21

what is a thermoplastic

Answer 21

fully polymerised solid that melts and solidifies

Question 22

how are polymer molecules joined

Answer 22

they are joined with strong covalent bonds

Question 23

what is a polymerization reaction

Answer 23

this is when chemicals are combined in a liquid form and allowed to cure in this reaction

Question 24

advantages of a polymerization reaction (4 points)

Answer 24

allows variable viscosity
can tailor properties
good adhesion to fibres
good mechanical properties

Question 25

describe thermoplastic molecules structure

Answer 25

molecules are in a linear structure, with no cross-linking between them. weak bonds hold them together

Question 26

benefits of having weak bonds and little cross-link in a thermoplastic material

Answer 26

it enables the material to melt and reshape when heated. little cross-link allows the material to be ductile