Question

A 50 mm diameter shaft is welded to a flat plate by fillet weld. What is the size of the weld if the shaft is required to transmit a torque of 1300 N.m? The permissible working shear strength of the weld material is 60 $N/m{m}^2$.

• A. 6.5 mm
• B. 7 mm
• C. 6 mm
• D. 8 mm

Answer 1

The correct option is D 8 mm

Shaft diameter, d = 50 mm

$Torque,T=1300N.m=13\times {10}^{5}Nmm$

Allowable shear strength,

$\tau =60N/m{m}^2$

If the weld size t, the torque transmission capacity of the weld at the throat is given by

$T=\left(0.707t\right)\times \frac{\pi d^2}{2}\tau$

$t=\frac{2T}{0.707\pi d^2\tau }=\frac{2\times 1300\times {10}^3}{0.707\times \pi \times {50}^2\times 60}$

= 7.8 mm, say 8 mm