Question

A shaft is subjected to the combined bending load 'M' and torsional load T. If the permissible shear stress is'ζ', the diameter 'd' of the shaft will be calculated by the relation

• A. $$d=16T/\pi \zeta$$
• B. $$d=32M/\pi d^3$$
• C. $$d = [\frac{16}{\pi \zeta} (M ^ 2 + T ^ 2) ^ {1/2}] ^ {1/3}$$
• D. $$d = [\frac{32}{\pi \zeta} (M ^ 2 + T ^ 2) ^ {1/2}] ^ {1/3}$$

Answer 1

Answer:

$$d = [\frac{16}{\pi \zeta} (M ^ 2 + T ^ 2) ^ {1/2}] ^ {1/3}$$

The diameter of a shaft subjected to combined bending load and torsional load is calculated using the maximum stress theory. The maximum stress is given by $\zeta_{max} =\frac{1}{2} \sqrt {\sigma_b ^ 2 +4 \zeta^ 2} =\frac{16}{\pi d^ 3} \sqrt {M^ 2 +T^ 2}$ The diameter of the shaft

$d = [\frac{16}{\pi \zeta} (M ^ 2 + T ^ 2) ^ {1/2}] ^ {1/3}$