## Wednesday, January 12, 2011

### Answers to ME Review Questions in Strength of Materials

Answers to the questions on Strength of Materials.
1. In the cross section of a shaft subjected to torsion, the stress is maximum at what location?
C. At the surface of the shaft
- The shear stress increases from the center (zero stress) to the outer(maximum stress).
- Application: Hollow shaft is a good replacement for solid shaft since only the less stressed portion (the center) is removed.

2. The stress experienced by a body under torsion is…
A. Shear stress

3. The stress experienced by a pressurized vessel is…
C. Tensile stress
-pressure tends to pull (tension) the shell of the vessel

4. The “Maximum Shear Theory”, one of the known theories of failure is also known as…
B. Guest’s theory

5. In the stress-strain curve, it is the point at which there is an appreciable elongation without corresponding increase in load.

D. Yield point

6. What will happen to the stress in a shaft under torsion if the diameter was decreased to half the original?
C. The stress will be increased eightfold
-stress, s=16T/pi(D^3), when you decrease the diameter to half the stress will be multiplied by eight (2^3=8)

7. What will happen to the stress of a body under compression if the force applied to it was doubled?
A. The stress will increase to twice the original
-stress, s = F/A, when, force F is doubled, the stress is also doubled.

8. Bending is actually a combination of two types of stresses…
C. Compression and tension

9. The Mises yield theory of failure is best applied to what type of materials?
B. Ductile materials

10. The slope of the line before the proportional limit in a stress-strain curve is also known as…
C. Modulus of elasticity

## Sunday, January 9, 2011

### ME Review: Strength of Materials

1. In the cross section of a shaft subjected to torsion, the stress is maximum at what location?
a. Near the center of the shaft
b. Between the surface and the center of the shaft
c. At the surface of the shaft
d. The stress is uniform from center to surface of the shaft

2. The stress experienced by a body under torsion is…
a. Shear stress
b. Compressive stress
c. Tensile stress
d. Bending stress

3. The stress experienced by a pressurized vessel is…
a. Shear stress
b. Compressive stress
c. Tensile stress
d. Bending stress

4. The “Maximum Shear Theory”, one of the known theories of failure is also known as…
a. Mises Yield theory
b. Guest’s theory
c. Venant theory
d. Rankine Theory

5. In the stress-strain curve, it is the point at which there is an appreciable elongation without corresponding increase in load.
a. Elastic limit
b. Rupture strength
c. Proportional limit
d. Yield point

6. What will happen to the stress in a shaft under torsion if the diameter was decreased to half the original?
a. The stress will be twice as much
b. The stress will be halved
c. The stress will be increased eightfold
d. The stress will remain the same

7. What will happen to the stress of a body under compression if the force applied to it was doubled?
a. The stress will increase to twice the original
b. The stress will increased to four times the original
c. The stress will remain the same
d. The stress will increase eightfold

8. Bending is actually a combination of two types of stresses…
a. Compression and torsion
b. Torsion and bearing
c. Compression and tension
d. Thermal stress and shear stress

9. The Mises yield theory of failure is best applied to what type of materials?
a. Brittle materials
b. Ductile materials
c. Elastomers
d. Metals only

10. The slope of the line before the proportional limit in a stress-strain curve is also known as…
a. Modulus of rigidity
b. Modulus of resilience
c. Modulus of elasticity
d. Modulus of toughness