Structure and vibration

Automated modal testing

Repeatable hammer or shaker tests with FRF quality checks and mode extraction, for the lab or for screening parts on the line.

Get in touch All use cases
When it makes sense
The same test on part after part

A hammer test by hand works for one part. It becomes slow and inconsistent when:

Hardware
What the station uses
Test part Soft supports Force sensor impact Accelerometers force response analog samples stored result Automatic hammer or shaker Signal conditioning IEPE or charge amplifier Data acquisition NI DAQmx or Dewesoft Industrial PC OpenEOL workflow FRFs and modes Pass or fail to PLC and MES Your part Station hardware
The station excites the part, reads the force and the response at the same time, and turns them into FRFs, modes and a pass or fail result.
The test
How the test works
  1. Put the part on soft supports and attach the accelerometers.
  2. Excite the part with the automatic hammer or the shaker, and record the force and the response together.
  3. Calculate the FRFs and the coherence, and repeat any measurement with low coherence.
  4. Fit the natural frequencies, the damping and the mode shapes, or compare the FRFs with known-good parts.
  5. Store the result with the serial number of the part.
Software
The open-source software behind it
Your plantReceives the results
MES and quality databaseResults over OPC UA, MQTT or SQL
OpenEOLRuns the workflow
Task engine Open sourceRuns the test sequence
GUI framework Open sourceOperator screens with live data and the result
Reports and database Open sourceOne FRF set for each part
AnalysisOpen-source tools in the workflow
sdypy-FRF Open sourceFRF estimation with coherence
sdypy-EMA Open sourceNatural frequencies, damping and mode shapes
pyuff Open sourceExport to UFF for other modal software
ScreeningPass or fail against known-good parts
DriversTalk to the hardware
OpenEOL IO drivers Open sourceNI DAQmx, Dewesoft, charge amplifiers and signal generators
pyTrigger Open sourceTriggered acquisition with pre-trigger samples
Open-source tools such as sdypy-FRF, sdypy-EMA, pyuff and pyTrigger run inside the OpenEOL workflow, so your engineers can read and change every step. The program itself is built for each project on top of them.
Related use cases
Other structural tests

Acoustic resonance testing for castings

Cracks and porosity found from the resonance peaks of the whole part.

High-speed camera vibration measurement

Operating deflection shapes from video, with no sensor on the part.

Blocked force measurement for motors and pumps

A noise source characterized once at its mounting points.

We can help
Planning a modal test station?

Get in touch.

janko.slavic@fs.uni-lj.si
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