ADMAS not applied

Altair Forum User

Hi.

 

I'm having a trouble running a simplified rollover simulation of a bus superstructure in RADIOSS. I'm trying to confer some mass to nodes in defined faces by ADMAS, but when I run the simulation, it appears that the mass I added makes not effect on the behavior of the structure. (I confirmed this by running a simulation whitout adding any masses, what threw me the exact same results).

 

There is the way wich I am applying the admas: 

 

1D > admas > nodes (here I select the nodes of the figure) > mass = 1200kg > Distributed mass (type 1) > Elem types = M-ADV1 > Create.

 

 

Is there a mistake in the way I am creating the admas?

 

Also, when I check the mass of the elements by tool >mass calc > elems, it show that the masses are right (around 400kg for the reference model and 1600kg for the model with mass added), and also compare the results for internal energy, contact energy and total energy and were all the same curves.

 

How Can I fix the error?

 

Thanks in advance for your help.

Altair Forum User

Hi Andres,

Is the model behavior in final .h3d for both the cases are the same?.

It will be good if you can share both the files (both _0000.rad, both .h3d and both T01 files) through the secure dropbox (link is provided in my signature).

Altair Forum User

Hi Andres,

Model file is missing in the files you have sent.

Please share the model files with and without ADMAS also (_0000.rad files). 

 

Altair Forum User

Hi George.

 

I send the files by the DropBox. Thanks in advance for your response.

Altair Forum User

Hi Andres,

This seems like an issue with the unit consistency followed in the model. I think you are following kg,mm, second unit consistency.

I recommend you to check the material parameters. Please correct it and try running.

Attaching the basic unit consistency followed for your reference.

 

 

 

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

Altair Forum User

Hi George.

 

I used one of the units system you gave me and it works. Thanks for your help.

 

Also, in the solver view, I am gettig a message with the elapsed time and other information, and I get an ERR of 88.7%, like this:

 

 NC=  506200 T= 9.9988E+02 DT= 1.9800E-03 ERR= 88.7% DM/M= 2.1976E-01
 ELAPSED TIME=      12419.49 s  REMAINING TIME= 

 

Do you know how can I reduce this error or what is it's cause?

Altair Forum User

Hi Andres,

The energy error percentage is the parameter that checks the energy conservation during each numerical cycle and it is computed by RADIOSS as a percentage. If the energy error is negative it means that some energy has been dissipated. If the error is positive there is an energy creation. Incompatible kinematic conditions in a model can lead to high positive energy..