// MechanicalAI Engineering — Vibration Analysis Tools
Miles Equation
G-Load Calculator
Random vibration Grms response for circuit card assemblies (PCB/CCA)
Grms = √( π/2 · fn · Q · PSD@fn )
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Gpeak = 3 × Grms
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Q = √fn or 1/(2ζ)
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Gtotal = Gpeak + Gmaneuver
Damping Ratio (ζ) — or select Q factor
ⓘ Using Q = √fn — Miles' conservative empirical rule for PCBs
Maneuver / Acceleration Loads (Quasi-Static)
Enter the applicable quasi-static maneuver load per axis. Gtotal = Gpeak(vibe) + Gmaneuver per axis (absolute sum — conservative).
Enter inputs above and click Calculate →
Quick Reference — Typical PCB/CCA Values
| Environment |
Typical PSD (G²/Hz) |
Typical fn (Hz) |
Typical Q |
Expected Grms |
| Ground Vehicle | 0.001 – 0.01 | 50–150 | 10–15 | 1–5 G |
| Shipboard | 0.001 – 0.04 | 50–200 | 10–20 | 2–8 G |
| Airborne (fixed-wing) | 0.01 – 0.1 | 100–400 | 10–20 | 5–20 G |
| Helicopter | 0.04 – 0.2 | 50–300 | 10–20 | 8–30 G |
| Rocket / Launch | 0.1 – 1.0 | 200–2000 | 10–50 | 20–100 G |
| MIL-STD-810 Cat 4 | 0.04 | — | 10 | per test |