How It Works - Stress Concentration Theory
+Stress Concentration Calculator
Calculate Kt for common geometries and Kf for fatigue analysis using Peterson's data.
MPa - for calculating actual max stress
Fatigue Notch Sensitivity (Kf)
MPa
✓
Low Stress Concentration
Kt less than 2.0 - acceptable for most applications
Stress Concentration Results
Theoretical Kt
--
Fatigue Factor Kf
--
Notch Sensitivity (q)
--
Maximum Stress
--
Geometry Ratio
--
Enter dimensions to calculate stress concentration factors.
Common Kt Values
| Feature | Kt Range |
|---|---|
| Hole in infinite plate | 3.0 |
| Sharp fillet (r/d = 0.02) | 2.5 - 3.5 |
| Generous fillet (r/d = 0.1) | 1.5 - 2.0 |
| U-groove, sharp | 2.5 - 4.0 |
| Keyway, sled runner | 1.6 - 2.0 |
| Keyway, profile | 2.0 - 2.5 |
| Thread root | 2.5 - 4.0 |
Notch Sensitivity Constants
| Material | sqrt(a) mm |
|---|---|
| Steel Q&T (700 MPa) | 0.25 - 0.35 |
| Steel Normalized | 0.40 - 0.50 |
| Steel Annealed | 0.50 - 0.65 |
| Aluminum | 0.50 - 0.65 |
| Cast Iron | q ~ 0 (use Kt=1) |