Why is it difficult to obtain modal parameters when measure extremely light damping structures and those results is inaccurate?

08 August 2017 1 4K Report

Hi everyone!

Now, i reading a book "modal testing: theory and practice" by Prof D.J.Ewin. And in this book, Prof D.J.Ewin wrote:" those with extremely light damping, for which measurements at resonance are inaccurate and difficult to obtain".

And, i understood that, when perform a modal testing for extremely light damping structures, results that obtained from measurements are inaccurate and of cause is difficult to obtain these results.

Yes, Of course, may be i understood wrong meaning of this sentence.

So Can you explain to me?

Thank you so much.

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