Optistruct No forces applied but no zero displacement found

Altair Forum User

Hi everybody,

 

I was running a test with optistruct using two simple cubes. They are both fixed at opposite ends. Their faces are separated by 0.1 mm and can, if pushed, become engaged in a contact (type SLIDE).

Type of analysis: nonlinear quasistatic.

 

Issue: Even if I fixed both cubes at their bases and there is no applied force and no contact is engaged (shcdist=0.001 and the solver warns me that no contact elements have been defined during the analysis), the cubes translate of 2 mm as if they are moving like rigid bodies.

 

I have already tried to constrain some more nodes, to no avail.

 

Any explanation for this thing by anyone?

 

Thank you in advance.

 

 

Find attached my .fem file to check

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Nachiket Kadu_22143

Altair Forum User said:

Hi everybody,

 

I was running a test with optistruct using two simple cubes. They are both fixed at opposite ends. Their faces are separated by 0.1 mm and can, if pushed, become engaged in a contact (type SLIDE).

Type of analysis: nonlinear quasistatic.

 

Issue: Even if I fixed both cubes at their bases and there is no applied force and no contact is engaged (shcdist=0.001 and the solver warns me that no contact elements have been defined during the analysis), the cubes translate of 2 mm as if they are moving like rigid bodies.

 

I have already tried to constrain some more nodes, to no avail.

 

Any explanation for this thing by anyone?

 

Thank you in advance.

 

 

Find attached my .fem file to check

Hi @Matteo

You gave displacement of 2 mm in x-direction in SPC contraints. Kindly make it zero.

Unable to find an attachment - read this blog

Altair Forum User

Thank you!

How did I end up not noticing it! Thank you very much