Mechanical Metallurgy Mock Test 1

1. A cubic shape body is subjected to stresses as shown in the figure below. If both are stresses are equal in magnitude, calculate the shear stresses on black and green planes.

2. In the following Potential energy vs. interatomic distance chart, interatomic force between the atoms will be zero at point __________

3. Consider a unit cube subjected to normal stress σx, σy, σz. Assume normal stress does not produce any shear stress on planes x, y, z. What will be the net strain along x direction?

4. A wedge shape body is under stress with principal stresses being σx=25MPa and σy=20MPa. At a certain angle β, the components of stresses are resolved into σ1 & σ2, where both σ1 & σ2 are normal to each other. If the value of σ1=18MPa, find the value of σ2?

5. Hooke’s law is obeyed till _____________ in stress-strain curve.

6. 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 _________

7. A strain gauge measurement made on the free aluminum surface indicates the principle strains 0.003 and 0.002. What are the principal stresses? (Given that poison's ratio for aluminum=0.33, young modulus = 70 GPa)

8. What is the relationship between engineering stress and true stress?
Given that; s = engineering stress, σ = true stress, e = engineering strain, ε = true strain.

9. A tensile specimen of 6 mm diameter and gauge length 25 mm reached a maximum load of 45 kN and fractured at 35 kN. The maximum diameter at fracture is 5mm. Determine the true stress at the fracture point.

10. Calculate the dilation of body, given that the initial volume is 250 mm² and final volume is 235.5 mm².