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Symmetric Stress ,Without Fixed Constraint

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Hi guys,

I have a symmetric structure which is imposed by symmetric stresses , and i wanna know the displacement of top point of this model without any fixed constraints.

But it cannot be solved ,says
"Failed to find a solution.
The relative error (2.8) is greater than the relative tolerance.
Returned solution is not converged.
- Feature: Stationary Solver 1 (sol1/s1)".

Does anyone have any experience on this kind of model? I don't wanna add fixed constraints, cause it is the most similar one to real situation. Is it possible?

Thanks for any help.
Emma

2 Replies Last Post Jan 28, 2015, 5:23 p.m. EST
Edgar J. Kaiser Certified Consultant

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Posted: 9 years ago Jan 28, 2015, 3:46 p.m. EST
Emma,

you could try to use Prescribed Displacement BCs to achieve a well defined model. Set the component with minimum effect to the load situation to zero.
If the structure, loading condition and deformation is really symmetric you can take advantage of the symmetry. There might be a neutral plane that can be used for Prescribed Displacement without loosing any detail.

Cheers
Edgar

--
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Emma, you could try to use Prescribed Displacement BCs to achieve a well defined model. Set the component with minimum effect to the load situation to zero. If the structure, loading condition and deformation is really symmetric you can take advantage of the symmetry. There might be a neutral plane that can be used for Prescribed Displacement without loosing any detail. Cheers Edgar -- Edgar J. Kaiser emPhys Physical Technology http://www.emphys.com

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Posted: 9 years ago Jan 28, 2015, 5:23 p.m. EST
Hi Edgar,

Thanks for your reply.

I made a simple rectangular block as example, and tried to set Prescribed Displacement on two sides (opposite) with X:0.2mm, y:0mm, z:0mm and X:-0.2mm,y:0mm, z:0mm. The dimension of the cuboid is :L=10mm, W=0.1mm, H=0.1mm. I thought it may easier to understand and get the data of displacement of center point.

But still has the same problem. Still don't wanna use the fixed constraint.

Oh... I made the structure directly without setting a axis. Maybe it is the problem, isn't it ? I'll have a try.


Regards
Emma

Hi Edgar, Thanks for your reply. I made a simple rectangular block as example, and tried to set Prescribed Displacement on two sides (opposite) with X:0.2mm, y:0mm, z:0mm and X:-0.2mm,y:0mm, z:0mm. The dimension of the cuboid is :L=10mm, W=0.1mm, H=0.1mm. I thought it may easier to understand and get the data of displacement of center point. But still has the same problem. Still don't wanna use the fixed constraint. Oh... I made the structure directly without setting a axis. Maybe it is the problem, isn't it ? I'll have a try. Regards Emma

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