ERROR #312

Altair Forum User

I am trying to perform a topology optimization of a wing and I am encountering this error:

#error 312

complinace is too large or negative.

 

I have tried to check the BC and if I give a Zsymm BCS, it gives me error 312

If I give a fixed BCS, then the optimization problem continues.

 

My optimization problem:

Min Weighted compliance and mass<0.2

 

I want to know why my model doesn't run with a zsymm BC?

 

Thanks,

Suraj.R

Altair Forum User

Hi Suraj,

 

Can you check dispalement in all direction and constrain the direction where displacement is more significant. Try this and check the results. 

Altair Forum User

@Prakash Pagadala

Thank you very much for the reply.

The displacement is more in the X direction. So should I constrain the dof1=0?

Thanks,

Suraj.R

Altair Forum User

Suraj,

 

Yes, try this and check if you get any reasonable result. 

Altair Forum User

@Prakash Pagadala

Thank you for the reply.

Yes! That's precisely my question. If the BCS changes, the complete problem changes right?

How come it works (gets solved...still the displacement value don't match my analytical value) when I constrain dof1&2 and doesn't when I apply Zsymm (dof3=dof4=dof5=0)?

I checked the loads as well...they are correct. The problem is in the BCS I guess.

Thanks,

Suraj.R

Altair Forum User

Suraj,

 

I am not sure until I see the model with loads and BCs but in general the rotational vectors parallel to the plane must be zero and displacement vector perpendicular to plane must be zero for symmetry. Check if this is respected or not in your model.