Question

A plate of width 120 mm has a central hole of 20 mm diameter. The plate is subjected to an axial tensile load of 30 kN. Yield stress is 550 MPa and the theoretical stress concentration factor is 3. If a factor of safety is 5, what will be the plate thickness?

• A. 3. 18 mm
• B. 4.18 mm
• C. 10.18 mm
• D. 8.18 mm

Answer 1

The correct option is D 8.18 mm


Given: P = 30 kN, w = 120 mm, d = 20 mm, K = 3, N = 5

$Stressconcentrationfactor,K=\frac{{\sigma }_{max}}{\sigma }$

${\sigma }_{max}=K\times \sigma =K\times \frac{P}{(w-d)t}$

$\frac{550}{5}=3\times \frac{30\times {10}^3}{(120-20)\times t}$

$=\frac{3\times 30{10}^3\times 5}{550\times 100}=8.18mm$