20/05/2026
A truck traveling at highway speed generates over 1 million vibration cycles in a single 8-hour journey. Most packaging engineers design for the drop. Almost none design for what happens before the truck arrives.
That's the problem Power Spectral Density (PSD) was built to solve.
PSD describes how vibrational energy is distributed across frequencies — how much acceleration energy exists at each band, expressed in g²/Hz. It tells you not just that your load is vibrating, but exactly which frequencies are doing the damage.
In road transport, energy concentrates in predictable zones:
📍 2–8 Hz → truck suspension. The dominant fatigue zone for most packaging.
📍 15–20 Hz → wheel and tire energy, varying with load and tire pressure.
📍 50–100 Hz → trailer deck resonance, depending on fill level.
If any of these match your packaging or product's natural frequency, you get resonance. And resonance is where failures happen — not in single dramatic events, but silently, over thousands of cycles, until something gives.
PSD analysis lets you design vibration tests that reflect this reality: not a generic shake table session, but a profile calibrated to the actual energy your load will face on the road.
A vibration test built on accurate PSD data protects your product.
A vibration test built on assumptions protects your assumptions.
👉 Full technical breakdown on our blog →
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The power spectral density is a complex mathematical calculation related to vibrational forces. In the packaging industry, vibrations are one of the key factors that might negatively affect the goods during the distribution cycle, and it is essential to keep them in mind. To this end, power spectral...