Roving sensor testing

Roving sensor measurement is a test where the structure is excited at the same location while responses are measured on the structure at multiple locations. This type of measurement is performed, for example, when you do not have enough sensors to measure responses simultaneously at all the points of interest.

To perform a roving sensor measurement you will have fixed excitation points, while the accelerometers will be moved (roved) to new positions in the structure at each measurement. To perform a roving sensor measurement in DIRAC, you need to make an import campaign, thus you need the DIR-Import license.

The workflow includes three steps:

• Creating the master file.
• Performing the single measurements.
• Merging the measurements.

Creating the Master file

The master file is a DIRAC project containing the complete design of experiment of the test, including all excitation and sensor positions.

To set up the master file, complete the next steps:

1. Start a New Measurement Campaign in DIRAC.
2. Create the complete design of experiment (adding all fixed excitation locations and all sensors position for all the roving measurement positions).
3. Save the DIRAC file.

Performing the single measurements

After creating the master file, you need to perform all the measurements, with the sensors placed in all the roving positions. For each single measurement, you will need to save a copy of the master file.

To perform the first measurement, complete the next steps.

1. Open the master file and save a copy. (You can also start a new project and use the functionality Measurement campaign from an existing setup).
2. Perform the FRF measurement.
3. Map the sensor channels of the current measurement to the MKII as they are in the front end.
4. Push the channel settings to the front end.

Merging the measurements

To merge all the single measurements, you need to start an import campaign using the master file as base and import all the single measurements, correctly mapping channels and excitations.

To merge the measurements, you need to:

• Start a new import campaign in DIRAC.
• Import all the single measurements.
• Map the sensor channels and excitations.

Create an import campaign

To merge all the measurements, you first need to create an import campaign, using as base the master file.

To create an import campaign, complete the next steps:

1. Open DIRAC.
2. Start a new project of type Import set-up from existing project.
3. Browse for the master file.

Import the single measurements

To import all the single measurements, complete the next steps:

1. Click on Data.
2. Drag and drop the DIRAC files containing the single measurements.
3. Select the presets All, containing untransformed sensors channels and excitations.

Map sensor channels and excitations

After importing the single files, you need to correctly map the sensor channels and the excitation to the corresponding ones.

To map sensor channels and excitations, complete the next steps:

1. Map the channels of the individual datasets to the sensor setup of the master file.
2. Map the excitations of the individual datasets to the sensor setup of the master file.