MESSAGE ID : 259 , MESSAGE ID : 87

Altair Forum User

Hi, I just started to use Radioss two weeks ago and I still have some difficulties. In my case, my calculation is running with a warning :

 

INTERFACE BUFFER INITIALIZATION
WARNING ID :          343
** WARNING : INITIAL PENETRATIONS IN INTERFACE

 

But then, after a few iterations I have an error message which is repeting :

 

 ** WARNING ZERO OR NEGATIVE VOLUME : 3D-ELEMENT ID : 7774
   ELEMENT IS SWITCHED TO SMALL STRAIN OPTION
MESSAGE ID :          259

 

And finally, the last one is :

 

 ** WARNING ZERO OR NEGATIVE VOLUME : 3D-ELEMENT ID : 7818
   ELEMENT IS SWITCHED TO SMALL STRAIN OPTION
MESSAGE ID :           87
 ** ERROR : INFINITE DOMAIN DETECTED (I7BUCE)
            IN INTERFACE ID=4
     ERROR TERMINATION

 

I have found no information concerning my problems, that's why I'm posting this here, I hope you could help me,

Regards

Altair Forum User

Hi,

Penetration is defined as the overlap of the material thickness of shell elements.The warning tells that in the interface defined there are some penetrations. Please recheck the interfaces.

 

The NEGATIVE VOLUME error happens when solid elements are very deformed and their characteristic length goes to 0. For large strain formulation the time step of an element goes to 0 when the element is compressed. 

In RADIOSS Starter input file (Runname_0000.rad), use Ismstr =2 in the solid property and  in RADIOSS Engine file (Runname_0001.rad) use the option/DT/BRICK/CST which will set the time step value tmin at which the solid elements will switch to small strain.This means that the solid elements using Ismstr =2 will use large strain formulation while their time step remains greater than tmin, and will then switch to small strain formulation. (/DT/BRICK/CST option is used to control the time step of the analysis. The time step becomes constant after reaching Tmin specified by the user )

 

The infinite domain error message may appear during sorting of contact interfaces when the distance between some nodes of the model becomes infinite.

One has to look at the model behavior to understand why some node coordinates are infinite. One common explanation is 'flying' nodes after failure of elements belonging to interface surfaces. In this case using Idel =2 in contact interfaces should fix this problem.

 

Recheck the interfaces defined in the model and try running the analysis.