Question

A 1.5 m long cantilever made of circular hollow section (CHS) has a diameter of 150 mm and thickness of 6 mm. It is connected to a 12 mm thick end plate by shop welding. The cantilever supports a vertical factored load of 4 kN at its free end at a horizontal eccentricity of 400 mm. Assume Fe 410 grade steel and 3 mm fillet weld stress in weld due to torsion.

• A. 16.42 MPa
• B. 18.42 MPa
• C. 21.56 MPa
• D. 34.32 MPa

Answer 1

The correct option is C 21.56 MPa

Size of weld = 3 mm

Throat thickness $t_e=3\times 0.7=2.1mm$

$I_{pw}=2\pi R^3{t}_e=2\pi \times {75}^3\times 2.1=5563687.5m{m}^4$

Factored shear force = 4 kN

$\text{Factored torsion =}4\times 0.4=1.6kN-m$

$\text{Stress due to torsion}=\frac{T_{u}R}{I_{pw}}$

$=\frac{1.6\times {10}^6\times 75}{5563687.5}$

= 21.56 MPa