This set of Mechanical Metallurgy Multiple Choice Questions & Answers (MCQs) focuses on “Creep Curve – 1”.
1. The thermo-elastic behavior is the only cause of anelastic effect and the elastic hysteresis loop on stress-strain curve.
Explanation: The thermoelastic result is one of the primary cause, but there are some other reasons also, such as the stress-induced ordering of substitutional and interstitial atoms, grain-boundary sliding, motion of dislocation, etc.
2. In the polymers, the energy dissipation and the anelastic behavior is caused by _________
a) elastic effect
b) grain boundary sliding
c) motion of dislocation
d) bond rotation
Explanation: In the polymers, the energy is dissipated by the bond rotation, moisture absorption, and a variety of other effects. The various energy-consuming effects are grouped together as the generic heading of the internal friction.
3. With anelastic behavior of the material, the stress and strain are out of phase during cyclic loading and unloading.
Explanation: The response of strain on applying stress is delayed in the anelastic material, so the stress and strain are out of phase in such cases.
4. The measure of the internal friction is the fractional decrease in ____________ per cycle.
a) stress amplitude
b) strain amplitude
c) vibrational energy
d) hysteresis loss
Explanation: The measure of the internal friction is the fractional decrease in vibrational energy per cycle because this gives the idea of energy absorbed in each cycle by anelastic behavior.
5. The internal energy dissipation at larger stresses and strains are generally called ____________
c) stored energy
d) extra energy
Explanation: At the larger amplitude and stress values, the energy loses are higher. This is called the damping; this occurs at the higher values compared to vibration.
6. The internal friction studies are generally conducted at ______ stress and ______ strains.
a) low, small
b) high, small
c) low, large
d) high, large
Explanation: The internal friction studies are generally conducted at low stress around 50 to 500 kPa. The strain is also kept very small.
7. The damping capacity of the material depends on the frequency of the vibration. It is not a material property.
Explanation: The damping capacity is a tangible property and solely depends on the metal/material and not on the condition of testing or the vibration frequency.
8. Which of the following material has the highest damping capacity?
c) Cast iron
d) Stainless steel
Explanation: The cast iron has the highest damping capacity because of the presence of graphite flakes in the structure. The graphite flakes absorb the elastic shock waves and do not transmit it to the surrounding.
9. The progressive deformation of the material at constant stress is called __________
Explanation: The slow progressive deformation of the material with time at constant stress is called creep. It is time and temperature-dependent phenomena.
10. To determine the creep rate, the curve is plotted between the _________
d) strain- temperature
Explanation: To determine the creep rate, the material at constant temperature is stress at continuous load. The elongation (strain) of the material with time is measured to determine the rate.
Sanfoundry Global Education & Learning Series – Mechanical Metallurgy.
To practice all areas of Mechanical Metallurgy, here is complete set of 1000+ Multiple Choice Questions and Answers.