Question

What force is required to punch a 20 mm diameter hole in a plate that is 25 mm thick?

Given: shear strength is 350 mN/m²

1. 549.8 kN
2. 350.8 kN
3. 788.1 kN
4. 522.9 kN

Answer 1

Correct Answer - Option 1 : 549.8 kN

Concept:

Punching Force is given by 

F = L × t × τ 

Where L is the perimeter of the hole, t is the thickness of the plate, \(τ\) is the shear strength od the work material.

For circular hole

Punch force = π × d × t × τ

Calculation:

Given:

d = 20 mm, t = 25 mm , τ = 350 MPa 

F = π × 20 × 25 × 350

F = 549.8 kN