Modal testing

Modal testing is the form of <a href="/facts/Vibration/sGgDqG71">vibration testing </a> of an object whereby the natural (modal) frequencies, modal masses, modal damping ratios and mode shapes of the object under test are determined.
A modal test consists of an acquisition phase and an analysis phase. The complete process is often referred to as a <a href="/facts/Modal_Analysis/BLxYhRcE">Modal Analysis</a> or Experimental Modal Analysis. 

There are several ways to do modal testing but impact hammer testing and shaker (vibration tester) testing are commonplace. In both cases <a href="/facts/Energy/wd8PrQM7">energy</a> is supplied to the system with a known frequency content. Where structural resonances occur there will be an <a href="/facts/Amplifier/pnRgxncC">amplification</a> of the response, clearly seen in the response spectra. Using the response spectra and force spectra, a <a href="/facts/Transfer_function/slDsh1lH">transfer function</a> can be obtained. The transfer function (or <a href="/facts/Frequency_response_function/zsHmnCJ4">frequency response function</a> (FRF)) is often <a href="/facts/Curve_fitting/zrLKw6Xj">curve fitted</a> to estimate the modal parameters; however, there are many methods of modal <a href="/facts/Estimation_theory/4nbgFDec">parameter estimation</a> and it is the topic of much research.

Modal testing open-in-new

Modal testing