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Showing posts with label Fracture. Show all posts
Showing posts with label Fracture. Show all posts

Saturday, February 8, 2020

FRACTURES SET 07
February 08, 2020

FRACTURES SET 07

FRACTURES SET 07

1. What is the deformation per unit length?

a) Strain
b) Stress
c) Toughness
d) Resilience

Answer: a

2. Ductility is indicated by _________
a) Percentage elongation
b) Percentage reduction
c) Poisson’s ratio
d) Elasticity

Answer: a

3. If a bar is doubled in length, what will be the strain induced?
a) 0.5
b) 1.0
c) 1.5
d) 2.0

Answer: b

4. Ductility is the opposite concept of _________
a) Toughness
b) Plasticity
c) Brittleness
d) Resilience

Answer: c

5. What term is used for the ratio of lateral strain to linear strain?
a) Bulk modulus
b) Elastic modulus
c) Shear strain
d) Poisson’s ratio

Answer: d

6. Material, if show identical properties in all directions, is said to be _________
a) Isotropic
b) Elastic
c) Ideal
d) Homogeneous

Answer: a

7. Which material has higher elasticity?
a) Rubber
b) Glass
c) Steel
d) Copper

Answer: c

8. _________ does not show linear stress strain relationship.
a) Rubber
b) Ceramic
c) Steel
d) Copper

Answer: a

9. The maximum stress up to which stress is proportional to strain is known as ________
a) Tensile stress
b) Compressive stress
c) Modulus of elasticity
d) Proportional limit

Answer: d

10. Yield strength represents resistance against _________
a) Fracture
b) Elastic deformation
c) Bending
d) Plastic deformation

Answer: d

11. Strain hardening causes more deformation on less stress application.
a) True
b) False

Answer: b

12. Necking causes drop in load after an ultimate tensile point.
a) True
b) False

Answer: a

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FRACTURES SET 06
February 08, 2020

FRACTURES SET 06

FRACTURES SET 06

1. What doesn’t favor a brittle fracture?
a) Tri-axial state of stress
b) A low temperature
c) High strain rate
d) Slow rate of loading

Answer: d

2. In a Charpy test, high hammer velocity ensures ______
a) High strain rate
b) Local stresses
c) Ductility in fracture
d) Low stress concentration

Answer: a

3. A crack will propagate if the decrease in _____ is at least equal to the energy required to create the new crack surface.
a) Plastic energy
b) Elastic energy
c) Toughness
d) Resilience

Answer: b

4. Automobile crankshaft is likely to undergo _____ fracture.
a) Ductile
b) Brittle
c) Intergranular
d) Fatigue

Answer: d

5. Strain energy required in a ductile fracture is ____ and _____ in brittle.
a) Higher, higher
b) Higher, lower
c) Lower, higher
d) Lower, lower

Answer: b

6. How does fracture surface appear in brittle fracture?
a) Rough and dull
b) Smooth and bright
c) Cup and cone
d) Fibrous

Answer: b

7. Ductile fractured surface appears _____
a) Dull
b) Smooth
c) Bright
d) Flat

Answer: a

8. Stress during cracking _____ in ductile fracture and _____ in brittle.
a) Increases, increases
b) Increases, decreases
c) Increases, constant
d) Decreases, decreases

Answer: c

9. All metals fracture in a ductile manner.
a) True
b) False

Answer: b

10. Little deformation takes place in brittle fracture.
a) True
b) False

Answer: a
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FRACTURES SET 05
February 08, 2020

FRACTURES SET 05

FRACTURES SET 05

1. On tensile loading, the elastic energy stored per unit volume will ___ with an increase in load.
a) Increases
b) Decreases
c) Remains constant
d) Increases or decreases

Answer: a

2. Surface energy associated with crack is proportional to ______
a) a
b) a2
c) a1/2
d) a-1

Answer: a

3. Surface energy of crack is given by __________
a) 4ϒsa
b) 2ϒs(a) 1/2
c) 2ϒsE
d) 2ϒsa

Answer: a

4. As length of crack increases, surface energy of crack ___
a) Increases
b) Decreases
c) Remains constant
d) May increase or decrease

Answer: a

5. Elastic strain energy ___ with increase in crack length.
a) Increases
b) Decreases
c) Remains constant
d) May increase or decrease

Answer: b

6. What does plastic deformation do on crack propagation?
a) Lowers surface energy
b) Sharpens the tip
c) Reduces required work
d) Increases concentration of stress

Answer: a

7. Orowan and Irwin theory is given for cracking in brittle materials.
a) True
b) False

Answer: b

8. Compressive stresses don’t make a serious problem when applied on brittle materials.
a) True
b) False

Answer: a

9. Above equicohesive temperature, material fail in __________
a) Intergranular
b) Ductile fracture
c) Brittle fracture
d) Trans granular

Answer: a

10. What is more effective for brittle fracture?
a) Spheroids
b) Sharp crack tips
c) Blunted crack tips
d) Nodules

Answer: b
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FRACTURES SET 04
February 08, 2020

FRACTURES SET 04

FRACTURES SET 04

1. Fracture always occurs above yield stress.
a) True
b) False

Answer: b

2. In ____ fracture, crack is unstable and propagates rapidly.
a) Ductile
b) Brittle
c) Shear
d) Tensile

Answer: b

3. Brittle fracture is a break in a brittle piece of metal that failed because stress exceeds _____
a) Cohesion
b) Adhesion
c) Yield stress
d) Tensile stress

Answer: a

4. Which of the followings is not a type of fracture in brittle materials?
a) Bright granular
b) Flat type
c) Neck
d) Chevron patterns

Answer: c

5. The crack may be __________ and ____________ depending on strength of grain boundaries.
a) Brittle, ductile
b) Trans granular, intergranular
c) Shear, cleavage
d) Fibrous, granular

Answer: b

6. In intergranular fracture, crack travels along grain boundaries.
a) True
b) False

Answer: a

7. In which type of brittle fracture, crack travels through grain boundaries?
a) Trans granular
b) Intra granular
c) Intergranular
d) Fibrous

Answer: c

8. Which theory explains brittle fracture?
a) Griffith
b) Cottrell
c) Taylor
d) Dislocation

Answer: a

9. What is the expression for maximum stress at the tip of crack?
a) σmax = 2 σ (ar)1/2
b) σmax = 2 σ (a/r) 1/2
c) σmax = 2 σar
d) σmax = 2 (σar)1/2

Answer: b

10. Elastic strain energy is proportional to ____________
a) (a)1/2
b) a
c) a2
d) a3

Answer: c
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FRACTURES SET 03
February 08, 2020

FRACTURES SET 03

FRACTURES SET 03

1. What region is first encountered by the material on a tensile test?
a) Elastic
b) Yielding
c) Strain hardening
d) Necking
 
Answer: a

2. What region is encountered after elastic deformation on a tensile test?
a) Strain hardening
b) Yielding
c) Necking
d) Fracture
 
Answer: b

3. Necking takes place after strain hardening.
a) True
b) False
 
Answer: a

4. Necking is a result of tri-axial tension.
a) True
b) False
 
Answer: b

5. What is cleavage plane for FCC materials?
a) {1 1 1}
b) {1 1 0}
c) {1 2 3}
d) {1 0 1}
 
Answer: a

6. What is the cleavage plane for HCP materials?
a) {1 2 3 0}
b) {1 0 0 0}
c) {0 0 0 1}
d) {1 0 0}
 
Answer: c

7. Which material fails by brittle fracture?
a) White cast iron
b) Steel
c) Aluminum
d) Copper
 
Answer: a

8. Which of the following materials don’t give brittle fracture?
a) White cast iron
b) Grey cast iron
c) Aluminum
d) Ceramics
 
Answer: c
9. When does brittle fracture is noticed?
a) On overloading
b) On sudden loading
c) Uniaxial loading
d) Compressing
 
Answer: b

10. What is characteristic of brittle fracture?
a) Prior warning
b) High speed
c) Necking
d) Ductile rupture
 
Answer: b
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FRACTURES SET 02
February 08, 2020

FRACTURES SET 02

FRACTURES SET 02

1. Ceramics generally undergo ductile fracture.
a) True
b) False
 
Answer: b
 
2. Necking means local deformation of a ductile material subjected to tensile loading.
a) True
b) False
 
Answer: a

3. Which of the following is not a stage of ductile fracture?
a) Nucleation of crack
b) Growth of crack
c) Coalescence of cracks
d) Development of tensile stresses
 
Answer: d

4. Cracks can’t nucleate at ____________
a) Grain boundaries
b) Crystal
c) Interfaces
d) Inclusion brittle particles
 
Answer: b

5. In aluminum copper system, which causes crack initiation?
a) Fe3C
b) CuAl2
c) Ti3Al
d) NiAl
 
Answer: b

6. What causes nucleation of crack in steel?
a) CuAl2
b) Ti3Al
c) Oxides
d) Fe3C
 
Answer: d

7. What is nucleation sites in copper?
a) CuAl2
b) Fe3C
c) Oxide inclusions
d) NiAl
 
Answer: c

8. Titanium aluminum alloys generate cracks due to ___________ particles.
a) Ti3Al
b) Fe3N
c) CuAl2
d) Oxide inclusions
 
Answer: a
9. On stressing a material, necking starts at a point of _______________
a) Plastic instability
b) Higher elastic modules
c) Higher regular arrangement
d) Higher stress
 
Answer: a

10. _____________ occurs during tensile deformation.
a) Compressive stress
b) Strain hardening
c) Forging
d) Shear stress
 
Answer: b
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FRACTURES SET 01
February 08, 2020

FRACTURES SET 01

FRACTURES SET 01

1. In _____________ fracture, the crack grows at a slow pace and a lot of plastic deformation occurs.
a) Ductile
b) Brittle
c) Fatigue
d) De-cohesive
 
Answer: a

2. ___________ amount of energy strain is required for ductile fracture.
a) Higher
b) Lower
c) Intermediate
d) Can’t say
 
Answer: a

3. What term is referred to the failure of highly ductile materials?
a) Ductile rupture
b) Orange peel
c) Patenting
d) Buckling
 
Answer: a

4. What appearance does ductile fracture under microscope give?
a) Irregular and rough
b) Smooth
c) Plate like
d) Shiny
 
Answer: a

5. Ductile fracture generally occurs in ____________
a) Metals
b) Ceramics
c) Plastics
d) Composites
 
Answer: a

6. In what matter ductile fracture occurs?
a) Trans granular
b) Intra granular
c) Catastrophically
d) Shear fracture
 
Answer: a

7. The planes along with which fracture takes place in metals are known as ____________
a) Slip plane
b) Cleavage plane
c) Twin plane
d) Basal plane
 
Answer: b

8. What is cleavage plane for BCC structure?
a) {1 0 0}
b) {1 1 1}
c) {0 0 0 1}
d) {1 1 0}
 
Answer: a
9. ___ metals and their alloys may fail by shear or cleavage.
a) FCC
b) HCP
c) BCC
d) SC
 
Answer: c

10. Cup and cone type fracture is a ____________ fracture.
a) Brittle
b) Ductile
c) Fatigue
d) De-cohesive
 
Answer: b
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