Midterm 2 Review

Question 1

What is strength?

Answer 1

The maximum amount of stress nessesary to reach noticeable strain (0.002ep)

Question 2

Ductility

Answer 2

The ability of a material to plastically deform before fracture

Question 3

Toughness

Answer 3

The ability of a substance to absorb energy by plastically deforming before fracture

Question 4

Resilience

Answer 4

The ability for a object to absorb energy elastically

Question 5

Hardness

Answer 5

The ability of a substance to resist surface deformation

Question 6

A factor of safety

Answer 6

A protection against manufacturing faults or general failures

Question 7

What is the modulus of elasticity in terms of interatomic force or potential energy

Answer 7

E is proportional to (dF/dr) ro

Question 8

What are the measurements of ductility?

Answer 8

%EL = (lf -li) / (li) x 100%
%RA (li - lf) / (li) x 100%

Question 9

Young’s Modulus values

Answer 9

Metals: 400-40
Cer: 1200 - 10
Poly: 4 - 0.2

Question 10

Poisson’s ratio

Answer 10

M: 0.33
C: 0.25
P: 0.4

Question 11

Yield Strength

Answer 11

M: 2000 - 10
c: N/A (fractures before noticeable stress
P 100-10

Question 12

Ultimate tensile strength

Answer 12

M: 2000 - 100
C: 1500 - 10
P 100 - 10