Question

Two solid shafts ‘A’ and ‘B’ are made of the same material. The shaft ‘A’ is of 50 mm diameter and shaft ‘B’ is of 100 mm diameter. The strength of shaft ‘B’ is ______ of that of shaft ‘A’.

1. one-half
2. double
3. four times
4. eight times

Answer 1

Correct Answer - Option 4 : eight times

Concept:

Solid Shaft:

• It is defined as the solid shaft are used to derive the pumps with Relative short shafts, is less than 30 to 50 foot long.
• They are used to drive almost all process pumps and Circulators.
• They provide more positive shaft & alignment which is especially important when the pumps have Mechanical seals rather than packing. the solid shaft used the axial adjustment of the pump.

Calculation:

Given,

Dia of shaft A = 50 mm 

Dia of shaft B = 100 mm 

According to the torsion Equation,

\(T = \;\tau \; \times \;{Z_P}\)

\(T\alpha \;{Z_P}\)

\({Z_P} = \;\frac{\pi }{{16\;}}{d^3}\)

\({T_B}/{T_A} = ({Z_P})_B/({Z_P})_A = {d_B}^3/{{d_A}^3}\)

\(\frac{{{T_B}}}{{{T_A}}} = \left( {{2^3}} \right) = 8\;\)