Question

$10$ mm diameter holes are to be punched in a steel sheet of $3$ mm thickness. Shear strength of the material is $400$ $N/m{m}^2$ and penetration is $40$%. Shear provided on the punch is $2$ mm. The blanking force during the operation will be

• A. $22.6$ kN
• B. $37.7$ kN
• C. $61.6$ kN
• D. $94.3$ kN

Answer 1

The correct option is A $22.6$ kN

Shear strength: $\tau =400N/m{m}^2$
Sheet thickness: $t=3m$
Diameter of hole: $d=10mm$
Shear on punch: $t_1=2mm$
Penetration of punch in fraction,
$p=0.4$
Blanking force when shear is applied on the punch
$=\pi dt\left(\frac{tp}{t_1}\right)\tau =\pi \times 10\times 3\times \left(\frac{3\times 0.4}{2}\right)\times 400=22.6kN$