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ALE model

Altair Forum User

Hi,

i am modeling a hat chaped specimen for a hopkison bar test, however i am getting excessive deformation so i think i should switch to an ALE model or Eulerian model. The problem is i don't know much about ALE modeling for solids, i started by simply choosing the ALE formulation in the material type and adding the ALE_CFD_SPH card but the results are not correct at all. What am i doing wrong? is it possible to attach the model and get your opinion on what i should do? the model i have right now is stil in lagrangian formulation wich works well until the excessive deformation starts to happen.

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Altair Forum User

Hi,

Ensure all the loading conditions and bc's applied are correct. Please go through Example 8 - Hopkinson Bar model in the Help Menu. This may give you some idea on modelling.

Also, there are several tutorials available on ALE formulation in the Help Menu. Please access them also.

The Hopkinson Bar model file is attached along for your reference. Please go through the same and revert if you find any difficulties.

Unable to find an attachment - read this blog

Altair Forum User

hi,

the issue is still persisiting, my main problem is with the ALE model not the SHPB modeling, when i use it i get -99.9% error for energy in one time step, the lagrangian model works well up to a certain point where the distorsion become too important and the time step starts to drop drastically, could i share my model so that you can see what the problem might be?

Altair Forum User

Hi,

Please share the files (_0000.rad, _0001.rad, _0000.out,_0001.,_.h3d and T01 files) through the secure dropbox link.

Altair Forum User

i just shared the files

Altair Forum User

i shared the wrong 0001.rad file here is the correct one

Unable to find an attachment - read this blog

Altair Forum User

Hi,

Received your files. I presume that the function for the imposed load is creating the issue.

In this file a high displacement is ramped in a very short duration. and so, the elements are getting badly distorted which causes the time step drop. I recommend you to ramp the load gradually and review the results.

Altair Forum User

have you checked the ALE model, is there anything wrong with my modeling besides the imposed velocity?

Altair Forum User

Hi,

I don't think there is anything else wrong with the models. Please retry with the modified function.