Modal Test --> show dynamic flexibility instead of accelerance

Would it be possible to add the possible to automatically evaluate the Modal test in the Displacement domain, when tests are done with Accelerometer.

In the Mechanical stuff we do, we want to check for Displacement, since it is much closer to our workpiece deviations, and gives us the possibly to guess how much a vibration leads do dynamic "infeed".

I can do it afterwards by integrate 2 times and so on, but it takes much time, for such a "easy" task. Some Presseting would be really great if possible.

Best regards

Daniel

Dear Daniel,

thank you for reaching out to us.

I spoke to our application engineer for Modal Test regarding this ticket, and this looks like a little less usual workflow than we're used to (as you know, FRF is by definition expressed in g/N), and we currently have no way of automatically evaluating the Modal test results in the Displacement domain.

It was suggested you try making the "regular" modal test (in g/N), and then use Frequency domain integration to work in the Displacement domain.

I will also report this to the developers as a feature request, in case they decide to pick this up whenever the next bigger overhaul of the Modal Test plugin is. We will certainly let you know, should such a feature be picked up by the developers.

Best regards,

Pika

Hello Pika,

yes the double integration in the freq domain is obviously possible, but it takes time to do the this.

since you have to select each signal in the individually in double integration, since you have to select it again individually in the 2D plots.

and than there for example the slider (to select the frequency for the Modal Geometry) that do not work and so on.

Either it would be optimal to have multi-select for the signal to make it fast or an additional page in the Modal test ( besides the FRF- the exact copy only for dynamic flexibility.

best regards

Daniel

Dear Daniel,

thank you for the follow up.

Would you mind expanding a little on the issues that you are experiencing? Perhaps share a video of the workflow you've mentioned with us?

As I currently understand, one of the issues is having to manually click each individual channel when setting up Frequency integration? If my understanding is correct, we could save you a couple clicks with filtering, channel names, and the option to enable selected channels or all channels:

By right- clicking into the Input channels slot, you can select to either check all channels, or just the selected ones. Specific channels can be selected with the help of Shift/Ctrl channels, and pressing the names (not checkboxes) of the of the individual channels.

Similarly, you could filter out the channels in Channel selector to make channel selection slightly easier.

I am not sure what you mean by "slider (to select the frequency for the Modal Geometry) that do not work". I can investigate this further once I know what exactly we are talking about.

Best regards,

Pika

HI, yes in the math --> double integration, i did not know the right click functionality to select all.

For me the best case would be something to "switch" easily, the selected FRF's

in the Modal Circle there is a drop down menu to select Receptance / Mobility / Accelerance to View. (see below) --> i know its much easier in the circle, but you get the idea.

I did not get my "workflow" as a video here, but here is a link 2025-03-05-22-42-19.mp4".

For me the biggest "annoying" thing is the time:

1. Selecting all FRF by hand, if needed for Phase aswell to get an " overview" of all measurments.
2. Doing it again for the Receptance measurement.
3. Especially if i want to do it for multiple excitations it takes very long "just" to visualize easily.
4. Suprisingly since last year, by default the raw time data are stored, that makes the modal tests much much bigger than they need to be ? --> I dont know if there is an "only save FRF" button, but i would be grateful if there was such a button
5. For that reason the Freuency integration of the FRF takes quite some time (>1minute)
6. The "Cursor" --> for selecting the frequency is only available and only interacts when using the original FRF's but not the double integrated charts shown in a 2D-Diagram

Hope this helps understand my view. if i miss an " easy workaround" please tell me ;)

Dear Daniel,

thank you for the clarification, I will pass it on to the developers. Additionally, spoke to our Application engineer regarding the key points from your last reply to ensure that you're getting the correct information.

The raw time data has always been stored to the datafile by default, as this allows for any recalculations that might be needed in Analysis. You could set the raw channels to "Not stored"

However, you won't be able to perform recalculations this way.

The cursor from the 2D graph is directly linked to the channels from the Modal test, which is why you cannot select it unless at least one original channel is assigned to the same 2D graph. Similarly, the calculated double integration cannot be animated.

Unfortunately, I do not think there's any workarounds around the two points above. As far as assigning the channels to a widget is concerned; If you always work with the same/similar geometry (and therefore have channels with the same names across all your datafiles), you could try using one of the following options:

1. Pre-making a full setup, including a display with assigned double integration channels. This way, you could simply load a setup without having to assign the channels to the widget every time you made a new measurement. If the calculated channels are meant to only be used during the Analysis, they can simply be set to "Offline" mode
2. If your datafiles do contain the same channels, but you hadn't calculated the double integrated channels yet, you could try using Apply action.
3. You could also try using the Import option in the Display manager, but this, as with the other options, will only work if you have the same channels in both datafiles: