Spectral Density Matrix Transformations
Reference criteria for a multiple degree-of-freedom (MDOF) random vibration test is generally provided in terms of an acceleration-based spectral density matrix (SDM). This SDM may be developed in terms of the auto-spectral densities (ASDs) and cross-spectral densities (CSDs) computed from the time histories acquired from an appropriately placed and oriented set of linear accelerometers. Such a direct measurement linear accelerometer based reference criteria will be denoted as SDMmeas. A second technique for defining a reference SDM is in terms of the accelerations associated with the six classical motion degrees-of-freedom as defined at an arbitrary point of origin. Such a reference will be denoted as SDMmotion. The objective at hand is to demonstrate the method of transforming between these two reference criteria spaces.Abstract
Contributor Notes
ABOUT THE AUTHOR
1 Conducted under contract to the US Army Redstone Test Center
Michael Hale earned a BSEE from Auburn University in 1983 and his MSE and PhD from The University of Alabama in Huntsville (UAH) Electrical and Computer Engineering Department in 1992 and 1998. Hale is currently employed as a principal research engineer with Trideum Corporation. Prior to retirement from 32 years of Federal service, he was employed as a senior electronics engineer and experimental developer in the Environmental & Component Test Directorate of the Army's Redstone Test Center (RTC), US Army Test and Evaluation Command (ATEC).
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