multi-variate mode indicator function MMIF


measure of the phase purity of the measured mode shapes using a multiple reference


  • NOTE 1 The MMIF is given as a frequency dependent eigenvalue problem: where: [A] = [B] = is the real part of the FRF is the imaginary part of the FRF is the force eigenvector is the mass matrix l is an eigenvalue.
  • NOTE 2 The MMIF comprises the eigenvalues resulting from the solution of the eigenvalue problem for each frequency
  • NOTE 3 MMIF = 0 indicates a perfectly excited mode shape
  • NOTE 4 MMIF >> 0 indicates either no resonances in the frequency range or inappropriately excited modes.
  • NOTE 5 The MMIF yields a set of exciter force patterns that can best excite the real normal modes. It is therefore a simple but effective method to check the adequacy of the selected exciter locations.
Glossary app image

ECSS Glossary mobile applications

ECSS Glossary mobile apps available from iOS and Android store and ECSS Glossary Plugin for MS Word available from Microsoft Appstore
Search the online Glossary