Topic: Manufacturing
In a metal sheet of 3 mm thickness, a hole of 7mm diameter needs to be punched. The yield strength in tension of the sheet material is 120 MPa and its ultimate shear strength is 100 MPa. The force required to punch the hole is
- A. 7.92 kN
- B. 11.6 kN
- C. 6.6 kN
- D. 13.9 kN
Answer: C. 6.6 kN
Explanation: Punching force F = pi * D * t * tau_s = 3.14 * 7 * 3 * 100 = 6594 N = 6.594 kN (approximately 6.6 kN).