Random Vibration Analysis — PSD Response
Power spectral density inputs, Miles equation, stress PSD output, and fatigue life estimation from broadband random loading.
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Quick Explainer
What is a PSD and why do we use it for random vibration?
A Power Spectral Density describes how signal energy distributes across frequency. Random vibration (road noise, turbulence) is characterized statistically. The PSD lets us compute RMS response efficiently via modal superposition without running millions of time steps.
How do I go from a stress PSD to a fatigue life estimate?
Compute the stress PSD at the critical location, then calculate statistical moments of the distribution. Apply a fatigue S-N curve weighted by the probability of each stress amplitude — methods like Dirlik give the expected damage rate per unit time.