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Energy Error

Karthic_22061

Hi,

I am doing interference fit problem in Radioss.

Facing issue with high positive energy error. Initially error % seems ok, but later it gradually increase to high positive value (99.9%)

The contact energy being Zero with Zero friction. Hourglass energy is also zero.

The out file attached for reference. Please do help solving the issue

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Altair Forum User

Hi Karthic,

For fully integrated elements, the Energy Error can be slightly positive since there is no Hourglass energy and the computation is much more accurate. Relatively small energy error % will be acceptable. Otherwise any positive energy error means energy has been created, normally indicates a model issue. Please recheck the model parameters, contact parameters ...etc in the model.

Karthic_22061

Hi George,

I noticed a discontinuous master surface.

Also in rbe2 creation T_X & T_z are free.

I have also attached the images for the contact parameters used. Please tell me where i went wrong

Thank you,

Have a great day

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

Altair Forum User

Hi Karthic,

The contact parameters seems fine and I don't think it's related with contact. Instead of Type 7 you can try with Type 24 also (set INACTI=-1).

Karthic_22061

Hi George,

I tried with Type24 contact, but I am getting 40% negative energy error,

with INTACT=1, I got 99% positive energy error.

Please have a look at the model attached and recommend me a possible solution to over come the issue of energy error.

Thank you in advance.

Altair Forum User

Hi Karthic,

If the simulation has a lot of sliding contact, then high energy error can be considered acceptable. the out file also seems fine.

I have made some minor changes and has sent you the model.

Karthic_22061

Hi George,

Thankyou for the reply.

High energy error acceptable with zero coefficient of friction ? As you told my model has fully sliding contacts.

Altair Forum User

Hi Karthic,

When the model has sliding contacts and very high deformations some resulting energy error may be developed in the model which is acceptable.

Please try with the file which I have sent you via mail.

Karthic_22061

Hi George,

I will try with the file you sent and update soon,

Mean while I have a doubt. In out file I shared, the energy error is low till the time of 0.1793 sec, after which there is noticeable rise in the error.( total event time 0.3 sec)

why this is happening ?..