Determination of Structural Damping Using the Impulse Response Function
Published May 1, 1991 by SAE International in United States
Annotation of this paper is available
This paper shows how the impulse response of each individual resonance in a frequency response function is calculated via a series of weighting functions and then used for damping calculations.
The technique is not new (1)* but previously it has been indicated (2, 3) that when using pseudo-random excitation, T > 2.5τ must be fulfilled in order to make accurate damping measurements, where T is the Fast Fourier Transform record length and τ is the decay constant of the damping.
It is shown that tolerable damping estimates can be made even if the record length T is as small as 0.05τ. This is because the short record length produces an aliasing phenomena on the amplitude of the impulse response function only - not on the slope of the decay.