Adams flexbody distributed forces

Question

Hello,

I have an flexible MBD model of an airctaft and a loadcase for air pressure in the form of distributed loads normal to the aircraft elements. I understand that using modal forces I can insert the load to the flexbody but only direction-wise i.e., if the load acts in all three coordinates, I 'd have to specify the load for each one.

However I only have the distributed load in the form of it beeing normal to each element. Is there a way to instert this load to Adams directly or must I find a way to break the load down to three components and insert them individually?

Thanks,

Josef K.

Jan Sotnik · Accepted Answer

Hi Josef,

please find attached the example. Note, I had to use PARAM,AUTOQSET,YES instead of SPOINT/QSET1 since it gives some strange number of modes. One should get 24 modes = 10 Fixed Boundary Normal modes + 13 Constrained modes + 1 residual vector mode (Modal Loadcase).

Note, there are some very useful SimCompanion articles pertinent to the topic:

Generating MNF files with Modal (Distributed) Loads

Generating Modal Neutral Files (MNF) using Nastran - Commands Explained

How to create an MNF using Nastran

Hope it helps.

Kind regards,

Jan

Attached Files (1)

Plate_with_1_modal_loadcase.7z