Question

Due to the centrifugal force acting on the rim, the flywheel arms will be subjected to

(a) tensile stress

(b) compressive stress

(c) shear stress

(d) none of the mentioned

I had been asked this question in a national level competition.

The question is from Fluctuation of Energy topic in chapter Turning Moment Diagrams and Flywheel of Machine Dynamics

Answer 1

The correct answer is (a) tensile stress

Explanation: The following types of stresses are induced in the rim of a flywheel:

1. Tensile stress due to centrifugal force,

2. Tensile bending stress caused by the restraint of the arms, and

3. The shrinkage stresses due to unequal rate of cooling of casting. These stresses may be very high but there is no easy method of determining. This stress is taken care of by a factor of safety.