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