Answer to Question #171333 in Mechanical Engineering for MARK

Question

A 65 mm diameter solid shaft is to be welded to a flat plate and is required to carry a torque of 1750 N-m. If fillet joint is used for welding what will be the minimum size of the weld when working shear stress is 66 MPa.

Answer 1

If, h= Size of fillet weld

t= throat thickness

T= Torque applied

The maximum shear stress developed in the weld material is given by,

$\tau_s =\frac{2×T}{\pi ×t×d^2}$

Given as

$\tau_s=66 N/mm^2\\ T=1750 ×1000Nmm\\ d=65mm\\$

Solving for t, we get

$t=\frac{2T}{\pi×\tau_s×d^2}=\frac{2×1750×1000}{3.14×66×65^2}$ =3.995=4 mm

Size of weld(h)=$\frac{t}{0.707}= 5.66mm$