250+ TOP MCQs on Bending Stresses and Vibrations and Answers

Steam and Gas Turbines Multiple Choice Questions on “Bending Stresses and Vibration”.

1. Vibration in rotor blades causes ________________
a) resonance
b) shut down of turbine
c) resonance & shut down of turbine
d) none of the mentioned
Answer: a
Clarification: When any particles vibrates with the same frequency as of natural frequency then it resonates.

2. Stresses are divided into ____________
a) Steady stress
b) Unsteady stress
c) Steady & Unsteady stress
d) None of the mentioned
Answer: c
Clarification: Stresses are divided into two types. They are
Steady stresses
Unsteady stresses.

3. Stress caused due to thermal loading is classified under ______
a) Steady stress
b) Unsteady stress
c) Breakage
d) None of the mentioned
Answer: a
Clarification: Stresses caused due to centrifugal forces, loading, thermal causing are classified into steady state stresses.

4. Stresses caused due to centrifugal forces are classified into unsteady state stresses.
a) True
b) False
Answer: b
Clarification: Stresses caused due to centrifugal forces are classified into steady stresses.

5. Unsteady stresses are caused due to interaction of rotating blades with ___________
a) Stationary feature
b) Viscous force
c) Friction
d) None of the mentioned
Answer: a
Clarification: Unsteady stresses are caused due to interaction of rotating blade with stationary features.

6. When working temperature is increased its rupture stress is ___________
a) Increased
b) Decreased
c) Working temperature is not related with rupture stress
d) None of the mentioned
Answer: b
Clarification: Increase in working temperature is associated with decrease in rupture stress.

7. In general, there are ______ types of stresses.
a) 2
b) 4
c) 3
d) None of the mentioned
Answer: c
Clarification: Stresses are classified into three types. They are
centrifugal stress
gas bending stress
centrifugal bending stress.

8. Centrifugal stress is a ________
a) shear stress
b) tensile stress
c) lateral stress
d) none of the mentioned
Answer: b
Clarification: Centrifugal stress is a tensile stress.

9. Centrifugal stress depends upon __________
a) Hub to tip ratio
b) Blade rotating speed
c) Hub to tip ratio & Blade rotating speed
d) None of the mentioned
Answer: c
Clarification: Centrifugal stress depends upon
blade density
hub to tip ratio
blade tip speed.

10. Centrifugal stress depends upon blade density.
a) True
b) False
Answer: a
Clarification: Centrifugal stresses depends upon
blade density
hub to tip ration
blade tip speed.