Materials - Week 2

Question 1

Attributes of metals?

Answer 1

Ductile, heat-conducting, strong

Question 2

Attributes of polymers?

Answer 2

Lightweight, cheap to form, corrosion resistant

Question 3

Attributes of elastomers?

Answer 3

Very flexible

Question 4

Attributes of ceramics?

Answer 4

Hard, brittle, corrosion and abrasion resistant

Question 5

Attributes of glasses?

Answer 5

Hard, brittle, transparent

Question 6

Attributes of composites?

Answer 6

tough, high strength/weight ratio

Question 7

Attributes of wood?

Answer 7

lightweight, cheap to form

Question 8

Attributes of foams?

Answer 8

lightweight

Question 9

What is strain?

Answer 9

deformation of a solid due to stress
ε= d /L
d = change of length (mm)
L = original(initial) length (mm) ε = strain (No units or %)

Question 10

What is tensile stress?

Answer 10

The external force per unit area of the material resulting in the stretch of the material

Question 11

What is the young modulus formula?

Answer 11

Young’s Modulus (E) = stress / strain E = σ /ε
E = (F / A) / (d / L)

Question 12

What are Ferrous metals?

Answer 12

Consists of iron and steel, so can rust and is magnetic

Question 13

What are Non-ferrous metals?

Answer 13

Metals and alloys without iron e.g aluminium

Question 14

Thermoset polymers

Answer 14

Contains irreversible biological bonds

Question 15

What is Mass?

Answer 15

scalar quantity of matter

Question 16

What is Stress (N/mm^2 or MPa)?

Answer 16

force divided by cross-sectional area

Question 17

What is Density (kg/m^3)?

Answer 17

mass per unit volume [ρ]

Question 18

What is Elastic modulus (GPa or GN/m^2)?

Answer 18

• the slope of the linear elastic part of the stress- strain curve
• Young’s modulus [E] describes tension or compression
• Shear modulus [G] describes shear loading

Question 19

What is Poisson’s ratio?

Answer 19

ratio of lateral axis strain in axial loading

Question 20

What is axial loading?

Answer 20

applying a force on a structure directly along an axis of the structure

Question 21

What does strength(MaP or MN/m^2) mean?

Answer 21

-Indicated by sigma f
-depends on material class (materials, polymers, etc)
-depends on mode of loading (tension, compression, shear, etc)

Question 22

What is force?

Answer 22

vector quantity causing a change in the position of a body

Question 23

What is weight?

Answer 23

force with which the Earth attracts a body

Question 24

What is toughness(kJ/m^2)?

Answer 24

resistance of material to the propagation of a crack

Question 25

Define propagation?

Answer 25

wave movement

Question 26

Name some engineering alloys

Answer 26

Aluminium alloys Copper alloys Lead alloys Magnesium alloys Molybdenum alloys Nickel alloys Steels Tin alloys Titanium alloys Tungsten alloys Zinc alloys

Question 27

Name some Engineering Polymers (the thermoplastics and thermosets of engineering)

Answer 27

Epoxies Melamines Polycarbonate Polyesters Polyethylene, high density Polyethylene, low density Polyformaldehyde Polymethylmethacrylate Polypropylene Polytetrafluorethylene Polyvinylchloride

Question 28

Name some Engineering Ceramics (fine ceramics capable of load-bearing application)

Answer 28

Alumina Diamond Sialons Silicon carbide Silicon nitride Zirconia

Question 29

Name some Engineering Composites (the composites of engineering practice)

Answer 29

Carbon fibre reinforced polymer Glass fibre reinforced polymer Aramid fibre reinforced polymer

Question 30

Name some Porous Ceramics (traditional ceramics, cements, rocks and minerals

Answer 30

Brick Cement Common rocks Concrete Porcelain Pottery

Question 31

Name some Glasses (ordinary silicate glass)

Answer 31

Borosilicate glass Soda glass Silica

Question 32

Name some Woods

Answer 32

Ash Balsa Fir Oak Pine Wood products (ply, etc.)

Question 33

Elastomers (natural and artificial rubbers)

Answer 33

Natural rubber Hard butyl rubber Polyurethanes Silicone rubber Soft butyl rubber

Question 34

Name some Polymer foams (foam polymers of engineering)

Answer 34

Cork Polyester Polyestyrene Polyurethane