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Modal Analysis of the ID31 Micro-Station

The goal is to experimentally extract a Spatial Model (mass, damping, stiffness) of the structure (shown on figure fig:nass_picture) in order to tune the Multi-Body model.

/tdehaeze/nass-micro-station-measurements/media/commit/563e827d01c1f18797f6fea23c4dd2dc4c991a80/modal-analysis/img/nass_picture.png
Picture of the ID31 Micro-Station. (1) Granite (2) Translation Stage (3) Tilt Stage (4) Hexapod (5) Dummy Mass

The procedure is represented on figure fig:vibration_analysis_procedure where we go from left to right.

/tdehaeze/nass-micro-station-measurements/media/commit/563e827d01c1f18797f6fea23c4dd2dc4c991a80/modal-analysis/img/vibration_analysis_procedure.png
Vibration Analysis Procedure

The steps are:

  • we obtain a Response Model (Frequency Response Functions) from measurements (described here)
  • the response model is further converted into a Modal Model (Natural Frequencies and Mode Shapes) (described here)
  • this is converted into a Spatial Model with the Mass/Damping/Stiffness matrices (described here)

Theses matrices will be used to tune the Simscape (multi-body) model.

The modes we want to identify are those in the frequency range between 0Hz and 150Hz.

The modal analysis of the ID31 Micro-station thus consists of several parts: