VT-740 Visual Vibro-Acoustics™

The Visual Vibro-Acoustics™ package combines all of the features of the Visual Modal™ package with the features of theVES-6000 Acoustics option.

The VES-4000 Basic Modal Analysis option in the Visual Modal™ package provides all of the tools you need for extracting modal parameters from experimental vibration measurements (FRFs). With Visual Modal™ you can identify the frequency, damping & mode shape of the modes of a structure from experimental data.

Modal parameter estimation (curve fitting) is done in three steps; 1) count the number of modes using a Mode Indicator function, 2) estimate the modal frequency & damping for each mode, 3) estimate a modal residue (a mode shape component) for each mode & each measurement



With the VES-6000 Acoustics option, you can post-process and display in animation Acoustic Intensity, Sound Pressure Level (SPL), Sound Power, and ODS’s from either Octave or Narrow Band measurements.  Vibro-acoustic data (acoustics & vibration), can be displayed on the same structure model, thus allowing you to correlate surface vibration with acoustic field measurements.

Acoustics Features

  • Animated display of vibro-acoustic data (acoustic & vibration)
  • 1/1, 1/3rd, 1/12th, 1/24th octave band measurements are displayed in bar chart format
  • Magnitudes can be displayed in Linear, Log, dB, dB Reference units
  • Acoustic Intensity is calculated from Cross Spectra or time waveforms
  • Sound Power through a surface is calculated from Acoustic Intensity
  • Narrow band can be converted to octave band measurements
  • A, B & C weighting can be applied to narrow band or octave band measurements
  • Noise sources can be ranked in a bar chart based on percentage of overall, dB, or watts.
  • Measurements can be tone-calibrated, using tone magnitude & phase

Modal Features

  • Mode Indicators for counting modes. Either a Complex Mode Indicator Function (CMIF) or a Multivariate Mode Indicator Function (MMIF) can be calculated, and all resonance peaks are counted above a scrollable noise threshold
  • Frequency & damping curve fitting. Either the Local or the Global MDOF Orthogonal Polynomial method can be used, with extra polynomial terms to compensate for out-of-band modes
  • Residue curve fitting. Either the MDOF Orthogonal Polynomial method or the SDOF Peak cursor method can be used
  • Quick Fit. Automatically executes all three curve fitting steps with minimal user interaction
  • Selected measurements and frequency bands can be used to improve modal parameter estimates
  • Frequency & damping estimates are graphically indicated on the Mode Indicator graph
  • A curve fit function is synthesized and overlaid on each measurement to graphically confirm each curve fit
  • All modal parameter estimates and curve fitting functions are saved with each measurement
  • FRFs can be synthesized using modal parameters
  • Modal Assurance Criterion (MAC). A bar graph and spreadsheet of the MAC values between all mode shape pairs. If MAC = 1, two shapes are the same.  If MAC < 0.9 two shapes are different.
  • Modal parameters can be imported & exported using the Universal File Format (UFF)
  • Mode shapes can be imported from Ansys, Emerson Process Management (CSI), FEMAP, LMS, I-DEAS, NASTRAN, Ono Sokki, Rockwell Automation Emonitor, Spectral Dynamics Star disk files