Maximum predicted environment (MPE) levels can be derived for acoustic, shock, and vibration levels where flight data is available. The enveloping for multiple sets of data can be performed using tolerance factors as described in the following papers.
Normal Tolerance Factors for Upper Tolerance Limits:
normal_tolerance_factors.pdf & Alternate Link
Uncertainty Margins in Aerospace Vibroacoustic Levels:
uncertainty.pdf & Alternate Link
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Example for P95/50 Normal Tolerance Limit:
50% chance of one data point exceeding the P95/50 level in 20 flights or ground tests
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A function for calculating tolerance factors is given in:
Matlab script: Vibrationdata Signal Analysis Package
>> vibrationdata > Miscellaneous > Statistical Distributions & Tolerance Factors > Tolerance Factors
– Tom Irvine
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