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Problem in quarter symmetric at boundary conditions 1

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Majid_F93

Geotechnical
Joined
Feb 2, 2018
Messages
27
Location
IR
Hi
My geometry of model is a square with a hole in center of it. Because of symmetry i am modeling a quarter of geometric.
my problem is that, when i model whole model my deformation in top of hole is about 8.5 mm, but when i model a quarter of model whit same loading, my deformation in top of hole is about 4.5 mm.
i use XSYMM and YSYMM in boundary condition. and my loading az uniform at top and right of model.

The picture of full model and quarter model is available in below:

1_entkga.jpg


2_pp9zmh.jpg
 
Take a closer look at both pictures and focus on the boundary conditions and loads. You don't have a quarter symmetry in your full model. Maximum a half symmetry.
 
If i remove boundary condition in bottom of model and exert a load like load on top of model, should result be same?
 
Yes, but then you might get trouble with convergence, since the part is not restrained to prevent rigid body movement. You could add the BC in the center axis, like in the symmetry model.
 
Thank you Mustaine3

I add symmetry boundary condition in vertival center axis(XSYMM) and horiontal center axis(YSYMM), i attain result like result of quarter model. is this approach ok?
 
You can verify your results against a hand calculation.
 
>is this approach ok?

Sure, as long as it fits to the situation you want to simulate, so an experiment or the reality.
 
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