ENGINE ERROR ID 79 : RADIOSS IMPLICIT STOPPED DUE TO LOADING DATA

Altair Forum User

Hi all,

 

I am working on an implicit case. First I applied a load on a group of nodes. Now I apply an imposed displacement. It worked fine for the first one but I get an error in the engine file for the imposed displacement :

 

MESSAGE ID :           79

 ** ERROR : RADIOSS IMPLICIT STOPPED DUE TO LOADING DATA **

      ISTOP=0

     ERROR TERMINATION

 

Here my imposed displacement input:

/IMPDISP/551
IMPOSED DISPLACEMENT ON TOP NODES
#  func_id       dir   skew_id   sens_id  grnod_id  frame_id     icoor
       601         Y                           803
#            x_scale             y_scale             t_start              t_stop
                   0       -3.000000e-02                   0

 

I see tstop but what is ISTOP ? 

 

Thank you in advance,

Alice

Altair Forum User

Hi Alice,

ISTOP is a keyword to show the error. This error message occurs when no loading has been defined in the model or when loading is zero during the first step in a nonlinear analysis.

Below are a few suggested workarounds for this error:

1.Check loading in the model.

2.Increase the initial time step.

 

Let us know how it goes!

 

Altair Forum User

Hi George, 

Thank you for your reply.

 

I do not see any problems in my imposed displacement input. 

I tried increasing timestep  (from 0.001 to 0.1) but it didn't work either. Then I changed from /IMPL/LINEAR to /IMPL/QSTAT which makes it work though the h3d file shows nothing happening (no displacement).

 

I sent you my starter and engine file through the secure dropbox link. Thank you.

Altair Forum User

Hi Alice,

I presume this error is because of the loading data.

In the loading function can you try with values below:

X         Y

0         0

50       1

100     1

 

Altair Forum User

Hi George, 

 

I tried this and it works fine, thank you a lot ! What I did : 

X     Y

0     0

1     1

2     1

 

However, I wonder about Time History Data : At time 0 displacement is zero but reaction forces, which I want to output, are non-zero. How can that be ? Plus, after t=1, reaction forces still increase though displacement stays constant. I don't understand what is going on... Find my request on the attached screenshot

 

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

Hi again, can you give me any support on my issue ? 

 

Thank you,

Alice

Altair Forum User

Hi Alice,

Please check the rigid bodies defined in the model. And also, check the model for penetrations or intersections.

Please share the .out files.

Altair Forum User

Hi Alice,

This is an issue related to RADIOSS implicit and our developers are working on it to get it done.

You can upload the *.h3d or A001 file in HyperGraph and can plot the reaction forces for the node.

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

Hi George, 

 

This enables to begin from zero indeed, thank you !

 

But still, I stop displacement at time 0.5 ms (see function in my post from april 28 above). Reaction forces should decrease but they keep increasing. How that ? 

 

Altair Forum User

Hi Alice,

The reaction force curve seems to be bit strange with implicit options. I'll check with this.

Meanwhile I tried the same in RADIOSS explicit, and the plot seems to be fine. The model files are attached along. 

<?xml version="1.0" encoding="UTF-8"?>

Unable to find an attachment - read this blog

Altair Forum User

Hi George,

 

Thank you for this update ! I check it later and come back to you.