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Impact Attenuator Analysis with Honeycomb structure resulting in error ID 55 and WARNING ID : 343

Hello everyone,

My name is Prasanna. I'm new to the Radioss world and to explicit analysis. I'm currently working on the crash impact analysis of the impact attenuator of our formula student car for season 2022. I did the modelling, but when I run the analysis, I get the errors

WARNING ID : 343
** WARNING : INITIAL PENETRATIONS IN INTERFACE
DESCRIPTION :
-- INTERFACE ID : 3
-- INTERFACE TYPE : Barrier_VS_IA
THERE ARE 3904 INITIAL PENETRATIONS
( CONCERNING 2121 NODES )

The warning disappears when I move the barrier so that the barrier and the impact attenuator have no contact at the beginning. BUt then the analysis runs indefinitely with 99.9% error through and through.

MESSAGE ID : 259

** WARNING ZERO OR NEGATIVE VOLUME : 3D-ELEMENT ID : 90711

ELEMENT IS SWITCHED TO SMALL STRAIN OPTION

I saw other forum messages and also tried the imstr=2 option but it doesnt seem to do much.

Would be great in this case if anyone could help me with this.

I've attached the model and the out files in the attachments.

Regards,

Prasanna

SRe22_Crash_Box_Simulation.zip

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English

Radioss

v2020.1

Accepted answers

All comments

Rogerio Nakano_21179

For the interface error, you need to set the parameters in the /INTER/TYPE7. At least the Igap and Gapmin.

if not set Gapmin, Solver will choose gap based on the master side segment characteristics.

For the solid element formulation for the honeycomb, you can set Ismstr=1.

if you have instructions, as tutorial, for the impactor problem, please review the steps.

Regards

Prasanna Venkatesh Sridharan

Hi,

Thanks for the information. I chose a Gapmin of 0.0 as both the parts have to be in contact all the time while its being pushed into the part.

The thing is that I have a previously made analysis but there are no instruction exactly for me to follow. I used the same design and cards as before but still getting the errors.

I'm trying with the gapmin = 0 and with ismstr = 1 and running the simulation. It seems to be running with error of 0% which from the first hand looks to be fine. But I've to wait and see how the result is.

Thanks once again for the information.

Regards,

Prasanna.

Rogerio Nakano_21179

Hi,

Thanks for the information. I chose a Gapmin of 0.0 as both the parts have to be in contact all the time while its being pushed into the part.

The thing is that I have a previously made analysis but there are no instruction exactly for me to follow. I used the same design and cards as before but still getting the errors.

I'm trying with the gapmin = 0 and with ismstr = 1 and running the simulation. It seems to be running with error of 0% which from the first hand looks to be fine. But I've to wait and see how the result is.

Thanks once again for the information.

Regards,

Prasanna.

Gap_min cannot be 0.0.

if you set 0.0 the solver will use information of the master side of the contact entities to estimate the Gap value.

Refer to the documentation

https://2021.help.altair.com/2021/hwsolvers/rad/topics/solvers/rad/inter_type7_starter_r.htm?zoom_highlightsub=/inter/type7

comments 10 and 11.

Regards