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RELATIVE ACCELERATION OUTPUT - SOL 112

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dankoonFANTOMAS

Aerospace
Jun 1, 2016
31
Hello everyone,


I want to calculate the response of a structure under a shock in NASTRAN.

I am using SOL 112 and the SPC/SPCD method: create SPC in my modal analysis input file (with restart lines), make a restart in my shock response file and using SPCD to apply my loading (TLOAD2).


The thing is, I am using PATRAN 2013 and I made RBE2 (I attached a picture of my structure for better understanding) to create a unique excitation node for my load and with the RBE2, the load is applied on the all structure.


So thr node 174482 is my excitation node but if I apply the load directly I will measure the total acceleration, so all my structure will move.

In my modal analysis I used this node with the SPC to create BCs so my structure is blocked at the nodes 174481, 174480, 174479, 174478.

So if I use this node to calculate the response of my structure under a transient load, I have to measure the relative motion of the response (and not to total). So I can keep my BcS.

I found that the parameter DYNSOLRELGRID allows you to use the REL (for relative) parameter of the acceleration output.

But I do not know how to set up it in my input file...

Can anyone help me?

Regards to the community
 
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