A tie bar is welded to a plate as shown in the figure. Find the strength of the weld if the size of fillet is 6 mm and working stress of fillet weld is 100 MPa.

Concept:

The strength of the fillet weld is found with the help of the formula given below;

Strength of weld (P) = σ × Lw × tt

Where σ = working stress in weld, L_w = total length of weld, and t_t = throat thickness of weld.

Calculation:

Given

Size of fillet weld (s) = 6 mm

Working stress (σ) = 100 MPa

Length of weld (L_w) = 100 + 100 + 100 = 300 mm

Throat thickness of fillet weld (t_t) = 0.7s = 0.7 × 6 = 4.2 mm

Strength of weld (P) = σ × L_w × t_t

Strength of weld (P) = 100 × 300 × 4.2 = 126000 N

Strength of weld (P) = 126 kN

Hence option (4) is correct.