In the flow curve equation given below, if the value of strain hardening exponent is increased, what will be the effect on the ductility of material? σ=Kεn; Where n is strain hardening exponent.

From an alloy, two specimens are machined and tested separately under tension and compression. The engineering stress-strain curves as well as the true stress-true strain curves for tension and compression are plotted in the same diagram. Identify the correct statements:
P. The engineering stress-strain curves in tension and compression are identical.
Q. The true stress-true strain curve in compression is lower than the true stresstrue strain curve in tension due to Bauschinger effect.
R. The true stress-true strain curve in tension is above the corresponding engineering stress-strain, curve.
S. The true stress-true strain curve in tension and compression are identical.

A

P, Q

B

Q, R

C

Q, S

D

R, S

Consider the following statements regarding ductility of bitumen: 1. Ductility is the property which does not permit bitumen to undergo large deformation without breaking. 2. Bitumen with high ductility are generally adhesive but do not have good cementing properties 3. Ductility must be ascertained at two different temperatures in order to pronounce on the suitability of the material Which of the above statements are correct?

A

3 only

B

2 only

C

1 only

D

1, 2 and 3

The Coffin-Manson relation is described as ________________ where Δεp = the plastic strain amplitude ε’f = fatigue ductility coefficient 2N = number of strain reversal to failure c = fatigue ductility exponent

A

Δεp/2=ε’f (2N)c

B

Δεp=ε’f (2N)c

C

Δεp/2=ε’f (N)c

D

Δεp=ε’f (N)c

The following flow curve shows the deformation behavior of the material in the plastic region. The material is deformed till ε1 and released; the material immediately reached to strain ε2. And the time strain reached to ε3. So, there is a delayed recovery of strain. This is behavior of material is called _________

A

recoverable elastic strain

B

delayed elastic strain

C

anelastic behavior

D

plastic strain

The most common form to express the flow curve is: σ=Kεn Here σ=stress, ε=strain, n=strain hardening exponent, and K is defined as stress when ε = _______

A

1

B

0.5

C

0

D

0.33

The rate of strain hardening and strain hardening exponents in the flow curve is always the same.

A

True

B

False

Output of a bulldozer is (i) Increased if drawbar HP of the tractor is increased for a given hauling distance (ii) Decreased if drawbar HP of the tractor is increased for a given hauling distance (iii) Increased if the hauling distance is increased for a given drawbar HP of the tractor (iv) Decreased if the hauling distance is increased for a given drawbar HP of the tractor

A

(i) and (iii) are correct

B

(i) and (iv) are correct

C

(ii) and (iii) are correct

D

(ii) and (iv) are correct

Output of a bulldozer is
(i) Increased if drawbar HP of the tractor is increased for a given hauling distance
(ii) Decreased if drawbar HP of the tractor is increased for a given hauling distance
(iii) Increased if the hauling distance is increased for a given drawbar HP of the tractor
(iv) Decreased if the hauling distance is increased for a given drawbar HP of the tractor

A

(i) and (iii) are correct

B

(i) and (iv) are correct

C

(ii) and (iii) are correct

D

(ii) and (iv) are correct

The MC curve reaches its minimum point before the AVC curve and the AC curve. In addition the MC curve intersects the AVC curve and the AC curve at their lowest point. The above statements are both true

A

Always

B

Often

C

Never

D

Sometimes

The following flow curve shows the deformation behavior of the material in the plastic region. The material is deformed till ε1 and released; the material immediately reached to strain ε2. So, there is an instantaneous recovery of strain. This is called _________

A

recoverable elastic strain

B

delayed elastic strain

C

snelastic behavior

D

plastic strain

In the flow curve equation given below, if the value of strain hardening exponent is increased, what will be the effect on the ductility of material? σ=Kεn; Where n is strain hardening exponent.

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