A study on the determination of optimal reference spectrum for random vibration control in environmental vibration test

For random vibration control in environmental vibration test it is desired that the spectra at the specimen attachment points coincide with the specified reference spectrum. However, this goal is seldom achieved because of the dynamic characteristics of shaker, fixture, and specimen and of the interactions between them in the test frequency ranges. This gaper proposes a method for the determination of the optimal reference spectrum which minimizes the spectral deviations between the specified reference spectrum and spectra at the specimen attachment points. The least square method is used for this purpose. This method requires only the measured FRFs at the control point and specimen attachment points in pre-vibration test and is shown through theoretical and experimental results to be effective.