ERROR IN INITIAL VELOCITY INPUT

Altair Forum User

Hi.

 

I'm having a trouble running a simplified rollover simulation of a bus superstructure in RADIOSS. I'm trying to apply a initial rotational velocity of 3.48 Rad/s, but when I run the EngineFile in the solver, I get the following error:

 

ERROR ID :          490
** ERROR IN INITIAL VELOCITY INPUT
DESCRIPTION :
   -- INITIAL VELOCITY ID : 2
   -- ROTVEL TITLE :
   WRONG REFERENCE FRAME ID=1

 

There is the way wich I am applying the rotational velocity: 

 

Utility > BC's Manager > Type 'initial velocity around an axis' > GRNOD > all nodes of all collectors of the model > Direction: X > Frame (here I have to create a reference frame, for that reason I create some rigid elements (RED 1D elements in the image), obtaining the gray reference frame) > V_r = 3.48 > Create

When I click create, that yellow point show up.

 

 

is there an error in the way I am creating the rotational velocity?

 

How Can I fix the error?

 

Thanks in advance for your help.

 

Altair Forum User

Hi Andres,

This seems to be an issue with the local system defined.

Go to card edit option and select 'systs' and select the local system referenced for the /INIVEL/AXIS and click on edit.

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

 

In the card edit panel select the type as Frame, and run the analysis.

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

 

 

Altair Forum User

Hi George.

 

The solution you gave me works.

 

Thank you very much.

Altair Forum User

Hi George.

 

I have another question regarding the initial velocity around an axis.

 

When I apply this velocity to my model, do I have to select a time in wich the velocity is stops acting on the nodes?, I ask because as the superestructure deforms, it appears that the velocity is still acting on the model, resulting in very large deformation that seems like will never stop. (See the image below).

 

 

Thanks in advance for your help.

Altair Forum User

Hi,

Normally we don't provide any stop time for /INIVEL/AXIS. 

For this component it seems an obvious behavior. You can run for some more time and review the deformations happening in the model. 

Please share the engine out file (_0001.out) also.

Altair Forum User

Hi George, thanks for your reply.

 

I have send you the files.

I'm concerned because the deformation that I obtain is very (VERY) large. I ran the model in a time of 1000 ms (twice the time of the previous figure) and it seems there are something that makes the model continue with the deformation after the impact.

 

 

I already checked the units of my model (I'm using mm, ms, g, N, MPa, mJ) and I think it's all right, but the deformation I'm getting is not normal (I think). I'm obtaining also an energy error of -1.2% so there is not a problem with the energy.

 

Altair Forum User

Hi,

The out file seems fine.

Please send the model file, engine file and T01 file to the dropbox so that we can review and update you.

Altair Forum User

HI George.

 

Thanks for your help.

 

I have send yo the files.

Altair Forum User

Hi Andres,

This deformation is because the whole base component (6mm component) and the added mass is acting over the structure which makes it to deform badly. There are no body panels or any ribs or stricture to take the load and so the whole load acting on the structure makes it deform.