RADIOSS non-linear analysis meaning of various parameters?

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

Hello,

 

I am working on my research project of drop testing an object using RADIOSS.

I am able to understand some of the parameters from the User Guide, but there are many parameters which are still not clear for me.

Listed below are the options that I would like to understand in more detail:

 

1. Control Card - ENG_RUN - This defines the end time for simulation, correct? Just want to make sure that this does not affect the resulting simulation, just limits the period which is simulated.

2. Control Card - ENG_ANIM_DT - We can define the time steps for which the animation files are generated. This does not affect the results, just like the above card, right?

3. Control Card - ENG_TFILE - What does this do and how is it useful?

4. Control Card - ENG_MON - What does this do and how is it useful?

5. How do I control the steps for which the solver solves the stiffness matrix? I believe that ENG_DT might be the one, but I don't understand the two parameters of this card.

6. Any other control card that is typically used for elasto-plastic analysis?

7. Interface - /INTER/TYPE7 - I really don't know why I am using this, or whether even I should use it? I only have a single component that is dropped from a height. There is contact between the surfaces of the component though.

8. BC Manager -> Initial Velocity - I am calculating the velocity of my object by v=sqrt(2*g*h). Should I apply this to the part or to the nodes? If to the nodes then should apply v or v/(no of nodes) for each node? Example, if I have v = 100 and 1000 nodes, should I apply the velocity as 100 or 100/1000=0.1?

9. Output block - I have no idea what this does? Just created because it was in the tutorial.

10. M36_PLAS_TAB Material model - In the tutorials the stress-strain curve is assigned to fct_ID1, but I cannot find it in my Hypermesh. There is fct_ID_E, and one field under the NFunc. If I provide it for fct_ID_E, RADIOSS gives an error that stress should decrease as plastic strain increases. If I provide to the field under NFunc, it also needs scale and EPS_DOT. What are these two parameters?. Eventually, where do I provide the curve? Also, after creating the material, is there a way to view the true stress - strain curve just to confirm that RADIOSS interprets it correctly? I also tried the Johnson Cook material model but the results were way wrong (strain of >2 when the fail strain is 0.08). So I just want to make sure the fields I am entering have correct interpretation by checking with the total stress strain curve.

 

I would like to get some good resources for standard method of performing certain analyses unsing RADIOSS. The tutorials just tell us what to do for specific use cases, and they also don't provide any explanation for why we are doing that. Any better references would be helpful.

 

I understand that I have asked way too many questions, even if you can answer some, that would be very helpful for me. Thanks in advance!

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