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A Review of Methodologies for Deriving Vibration and Shock Test Severities.

This paper was generated by the CEEES Technical Advisory Board for Mechanical Environments in the period 2006 to 2008. It contains 11 pages of text and 31 figures.

The paper arose because it was apparent to the Technical Advisory Board for Mechanical Environments that no single method, for assessing road transportation vibration data, has general acceptability. The disparity between the various methods used for deriving test severities from measured environmental data appears to arise as a result of differing opinions as to the most appropriate approach for addressing both time variant and transitory aspects of the dynamic responses. In addition variations appear to exist in how different methodologies include unquantified variables in the actual life cycle conditions. This paper specifically considers the methodologies for deriving test severities for the road transportation dynamic environment.

A number of the approaches are in current use to derive vibration test seventies from measured data and described in this paper. The advantages and disadvantages of each are presented. The actual methods addressed are those which appear in a number of current or proposed national standard test requirements. An example of the use of each method is presented. That example is based upon measurements in a transport aircraft.


The Problem
The Differing Test Generation Approaches
     Conventional Power Spectral Density (PSD) Enveloping Approach
     The Peak Hold Spectra Approach
     The Foley or SANDIA Approach
     The Aberdeen Proving Ground Approach
     The Amplitude Probability Density Approach
     The Maximum Response Spectra (MRS) / Fatigue Damage Spectra (FDS) Approach

CEEES is a confederation of the environmental engineering societies of

the United Kingdom (SEE),
France (ASTE),
Germany (GUS),
Sweden (SEES),
Switzerland (SSEE),
Finland (KOTEL),
Belgium (BSMEE),
the Netherlands (PLOT),
Italy (AITPA),
Czech Republic (NACEI)
Austria (ÖGUS)
Portugal (SOPSAR)