In random vibration analysis, the load is given as a PSD (power spectral density). The values are often $G^2/Hz$, but I have an example where the PSD is a pressure $Pa^2/Hz$. The value is written as $(100 N/m^2)^2/Hz$ which brings me to these questions:

  1. Is that value $(100 \;N/m^2)^2/Hz$ equal to $10000 \;(N/m^2)^2/Hz$? (The results of the analysis imply that the answer is Yes, but I want to confirm my understanding.)
  2. Are both styles of writing the value acceptable? Is one style more common or acceptable than the other? For example, I have never seen an acceleration PSD written as $(5 \;G)^2/Hz$ to represent a value of $25 \;G^2/Hz$.
  • $\begingroup$ I would guess they are using $\text{hPa}^2/\text{Hz}$ in their application because $100\text{N}/\text{m}^2 = 1 \text{hPa} = 1 \text{mbar}$. $\endgroup$
    – alephzero
    Apr 26 '19 at 15:04
  • $\begingroup$ just a question, in the first case, G2/Hz, how do you insert it in a simulation software to replicate? $\endgroup$ Aug 28 '19 at 11:27

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