35. A shaft has a circular cross section with a diameter of . The allowable shear stress of  the shaft is . If  and  are independent, estimate the mean and standard deviation of the power that can be transmitted at  using the First Order Second Moment Method.

Solution

The maximum shear stress is given by

The maximum shear stress should be below the allowable shear stress,

Thus the allowable torque is

And the transmitted power is

Let

where .

Using FOSM, we have

Ans.