ANSYS WB 13.0 - Reaction Forces from Harmonic

[aulrich]

Hello all,

I am attempting to obtain reaction forces from a harmonic simulation in ANSYS WB 13.0. It appears the only way to do this is with some command objects that grab this info from ANSYS Classic.

I found the following blog that is similar to what I am trying to do:

http://www.padtinc.com/blog/the-focus/retrieving-accurate-psd-reaction-forces-in-ansys-mechanical

Using the same commands, I tried to do this in my simulation, but the results always show up in as 0 in WB.

Here is what I did:

1. Created a named selection in the model - a collection of surfaces that represent a support in my model.

2. Added a command object in my modal sim to ensure the modal saves all the results:

outres,all,all
mxpand,,,,yes,,yes​

3. Added a command object in my harmonic solution to calculate the reactions on the named selection and bring it back into WB:

/post1
set,10,1
cmsel,s,react_area1
esln
fsum
*get,my_fsumx,fsum,0,item,fx
*get,my_fsumy,fsum,0,item,fy
*get,my_fsumz,fsum,0,item,fz
allsel​

I thought maybe I was calling on the wrong data with the "set" command, but I double checked it and it seems correct.

Anyone have suggestions on what I'm doing wrong?

Thanks,
Andri Ulrich

 

[0rel]

Hi Andri,

I'm not familiar with the subject, but in the link you are giving, they are doing a random vibration analysis. Are you sure you can do the same for a harmonic response (if you are using this module) ?

Regards,


0rel

 

[aulrich]

Orel,

I am using the harmonic response module. And yes, I am unsure if the method used in the link will work for harmonic, but I am hoping it will, perhaps with slightly different code?


Andri

 

[aulrich]

Still no luck with this.

I have done some more troubleshooting and found that I am getting the following error in my harmonic response run:

...
SELECT COMPONENT REACT_AREA1

SELECT ALL ELEMENTS HAVING ANY NODE IN NODAL SET.

93 ELEMENTS (OF 18289 DEFINED) SELECTED FROM
52 SELECTED NODES BY ESLN COMMAND.

*** WARNING *** CP = 23.665 TIME= 13:33:14
No element nodal forces available. The FSUM command is ignored.

*GET MY_FSUMX FROM FSUM ITEM=ITEM FX VALUE= 0.00000000

*GET MY_FSUMY FROM FSUM ITEM=ITEM FY VALUE= 0.00000000

*GET MY_FSUMZ FROM FSUM ITEM=ITEM FZ VALUE= 0.00000000
...

Anyone have any tips on how to fix this? Looks like the harmonic is not calculating the nodal reactions needed for the FSUM command.

Andri