Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Material Gooorrrrlllll! > Chapter 8: Failure > Flashcards

Chapter 8: Failure Flashcards

1
Q

Ductile metals exhibit———plastic deformation with———energy absorption before fracture.

A.) substantial, high
B.) little, low
C.) substantial, low

A

A.) substantial, high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

A stable crack will extend with———in the applied stress.

  • no change
  • a decrease
  • an increase
A

An increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Ductile fracture requires———strain energy compared to brittle fracture.

  • higher
  • lower
  • equivalent
A

Higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What type of fracture is this?

A mode of fracture attended by extensive gross plastic deformation

A

Ductile Fracture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What type of fracture is this?

Fracture that occurs by rapid crack propagation and without appreciable macroscopic deformation

A

Brittle Fracture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

———materials show virtually 100% reduction in area at fracture.

  • brittle
  • Moderately ductile
  • highly ductile
A

Highly ductile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Most ductile materials experience a ——— amount of necking before fracture.

  • significant
  • moderate
  • negligible
A

Moderate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The long axis of an elliptical crack during the process of ductile fracture is———to the direction of the applied stress.

  • parallel
  • perpendicular
  • unrelated
A

Perpendicular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Fractographic studies are performed using a(n)———microscope.

  • optical
  • scanning electron
  • transmission electron
A

Scanning electron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

A scanning electron fractograph showing spherical dimples is indicative of fracture from———stress.

  • tensile
  • compressive
  • shear
A

Tensile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

A scanning electron fractograph showing parabolic dimples is indicative of fracture from———stress.

  • tensile
  • compressive
  • shear
A

Shear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The fracture surface of a brittle fracture is———.

  • curved
  • smooth
  • flat
A

Flat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Cracks in a transgranular fracture propagate———grain boundaries.

  • until
  • through
  • along
A

Through

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Cracks in an intergranular fracture propagate———grain boundaries.

  • until
  • through
  • alone
A

Along

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What type of fracture is this?

Fracture of polycrystalline materials by crack propagation through the grains

A

Transgranular fracture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What type of fracture is this?

Fracture of polycrystalline materials by crack propagation along grain boundaries.

A

Intergranular fracture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The magnitude of localized stress is highest———the crack tip.

  • at
  • near
  • far from
A

At

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

A maximum stress much higher than the applied stress results from a———micro crack with a———tip radius of curvature.

  • short, small
  • long, large
  • long, small
A

Long, small

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The———is a measure of the degree to which an external stress is amplified at a crack tip.

  • stress concentration factor
  • modulus of elasticity
  • specific surface energy
A

Stress concentration factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

In the example above, if the applied stress is increased to stress= 80MPa, then the critical crack length, a, will be equal to———um.

  • 16.4
  • 2.05
  • 4.1
A

2.05

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is this equation?

Stress(m)= 2*stress(0)((a/pt)^1/2

A

Tensile loading, computation of maximum stress at a crack tip

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is this equation?

K(t)=stress(m)/stress(0)=2(a/pt)^1/2

A

Tensile loading, computation of maximum at a crack tip

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Stress(c)=((2Ey(s))/pi*a)^1/2

A

Critical stress for crack propagation in brittle material

24
Q

The magnitude of localized stress is highest———the crack tip.

  • at
  • near
  • far from
A

At

25
Q

A maximum stress much higher than the applied stress results from a———micro crack with a———tip radius of curvature.

  • short, small
  • long, large
  • long, small
A

Long, small

26
Q

The———is a measure of the degree to which an external stress is amplified at a crack tip.

  • stress concentration factor
  • modulus of elasticity
  • specific surface energy
A

Stress concentration factor

27
Q

In the example above, if the applied stress is increased to stress= 80MPa, then the critical crack length, a, will be equal to———um.

  • 16.4
  • 2.05
  • 4.1
A

2.05

28
Q

K(c)=Ystress(c)squrt(pi*a)

A

Fracture toughness-dependence on critical stress for crack propagation and crack length

29
Q

K(Ic)=Ystresssqurt(pi*a)

A

Plane strain fracture toughness for mode 1 crack surface displacement

30
Q

Fracture toughness is common in units of———.

  • MPa
  • MPa*m
  • MPa*squrt(m)
A

MPa*squrt(m)

31
Q

Plane strain fracture toughness is used when the specimen thickness is———the crack dimensions.

  • much greater than
  • equal to
  • much less than
A

Much greater than

32
Q

The plane strain fracture toughness, K(Ic) decreases with———strain rate the———temperature.

  • increasing, increasing
  • decreasing, decreasing
  • increasing, decreasing
A

Increasing, decreasing

33
Q

Stress(c)=(K(Ic))/(Ysqrt(pia))

A

Computation of design

34
Q

a(c)= 1/pi((K(Ic))/(stressY))^2

A

Computation of maximum allowable flaw length

35
Q

If K(Ic) and stress(c) are determined by design constraints, then a(c) is———.

  • variable
  • fixed
  • irrelevant
A

Fixed

36
Q

A———can be used to find internal or surface flaws in in-service components and during quality control in manufacturing.

  • destructive test
  • non-destructive test
  • tensile test
A

Non-destructive test

37
Q

A———is used to design to account for flaws which result in lower strength and toughness.

  • safety factor
  • critical crack length
  • critical stress
A

Safety factor

38
Q

A technique of fracture Analysis used to determine the stress level at which preexisting cracks of known size will propagate, leading to fracture.

A

Fracture mechanics

39
Q

A small flaw (internal or surface) or a structural discontinuity at which an applied tensile stress will be amplified and from which cracks may propagate.

A

Stress raiser

40
Q

The measure of a material’s resistance to fracture when a crack is present

A

Fracture toughness (K(c))

41
Q

The condition, important in fracture mechanical analyses, in which, for tensile loading, there is zero strain in a direction perpendicular to both the stress axis and the direction of crack propagation; this condition is found in thick plates, and the zero-strain direction is perpendicular to the plate surface.

A

Plane strain

42
Q

For the condition of plane strain, the measure of a material’s resistance to fracture when a crack is present.

A

Plane strain fracture toughness (K(Ic))

43
Q

Impact testing is used to determine fracture characteristics at———temperature and———loading rates.

  • high, high
  • low, low
  • low, high
A

Low, high

44
Q

In the———impact test, the specimen is supported on both sides with impact on the side opposite the v-notch.

  • charpy
  • izod
  • v-notch
A

Charpy

45
Q

The———is calculated from the difference between the initial height, h, and the maximum height, h’, of the impact hammer.

  • plane strain fracture toughness
  • yield strength
  • energy absorption
A

Energy absorption

46
Q

The ductile-to-brittle transition is related to the———dependence of the measured impact energy absorption.

  • initial hammer height
  • temperature
  • applied force
A

Temperature

47
Q

The ductile-to-brittle transition occurs at approximately———degrees C for A283 steel.

  • 0
  • 50
  • 100
A

50

48
Q

Increase the carbon content of a steel alloy will———the ductile-to-brittle transition temperature.

  • increase
  • decrease
  • not change
A

Increase

49
Q

One of two tests that may be used to measure the impact energy or notch toughness of a standard notched specimen. An impact blow is imparted to the specimen by means of a weighted pendulum.

A

Charpy test

50
Q

One of two tests that may be used to measure the impact energy of a standard notched specimen. An impact blow is imparted to the specimen by a weighted pendulum.

A

Izod test

51
Q

A measure of the energy absorbed during the fracture of a specimen of standard dimensions and geometry when subjected to very rapid (impact) loading Charpy and Izod impact tests are used to measure this parameter, which is important in assessing the ductile-to-brittle transition behavior of a material.

A

Impact energy (notch toughness)

52
Q

The transition from ductile to brittle behavior with a decrease in temperature exhibited by some low-strength steel (BCC) alloys; the temperature range over which the transition occurs is determined by Charpy and Izod impact tests.

A

Ductile-to-brittle transition

53
Q

Stress(m)= (stress(max)-stres(min))/2

A

Mean stress for cyclic loading-dependence on maximum and minimum stress levels

54
Q

Stress(r)= stress(max)-stress(min)

A

Computation of range of stress for cyclic loading

55
Q

Stress(a)= stress(r)/2= stress(max)-stress(min)/2

A

Computation of stress amplitude for cyclic loading

56
Q

R=stress(min)/stress(max)

A

Computation of stress ratio

57
Q

Failure, at relatively low stress levels, of structures that are subjected to fluctuating and cyclic stresses

A

Fatigue

Material Gooorrrrlllll! (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions