Tools › Structures › Stress Concentrations › Rounded Square Hole › Example
Rounded square turned 45° (diamond) under tension along a diagonal: 7.8, against Inglis 1 + 2√(d/ρ)
| Tool | Rounded Square Hole |
| Source | Savin, G. N. (1961). Stress Concentration Around Holes, translated by E. Gros. Pergamon Press, Oxford. Chapter III; Inglis, C. E. (1913). "Stresses in a Plate Due to the Presence of Cracks and Sharp Corners." Transactions of the Institution of Naval Architects, Vol. 55, pp. 219–241 (1 + 2√(d/ρ)). |
| Level | Graduate |
Problem
The 0.25 in square hole with 0.015 in corner radii is rotated 45° so that its diagonals lie on the plate axes, and the plate carries 10,000 lb/in in y (tension along a diagonal) with t = 0.1 in. Find the peak stress concentration factor at the corners on the axis across the load and compare it with Inglis's estimate for a slender ellipse of the same corner distance and tip radius.
Inputs to Enter
- N_xx = 0, N_yy = 10000 lb/in, N_xy = 0, t = 0.1 in
- W = 0.25 in, ρ = 0.015 in, β = 45°
- r = 0.175 in (corner distance), θ = 90°
Answers
- K_t = 7.8 at the side corners (σ_edge,max = 780 ksi)
- Corner distance d = 0.175 in, d/ρ = 0.175/0.015 = 11.67
- Inglis estimate 1 + 2√(d/ρ) = 7.8, matching the tool
Notes
Set β = 45°, N_yy only and ρ = 0.015 in. The explanation page gives this comparison; it is the only published check of the Savin map's corner values on the page.