difference between 2d and 3d results

[Newuser2006]

hi to all,a forming analysis is done in both 2d and 3d parts.but at the end i have a huge difference btw both results

 

[bassmanjax]

What results are you seeing the differences in?

Martin Stokes CEng MIMechE

 

[Newuser2006]

actually iam interested in the translations in the y-axis,to see how much is the deformation ratio.

 

[Bat585]

I think you have to be careful of the way you have meshed your 2D part : you can use plane stress elements or plane strain elements.

Try both but I think that plane strain elements will give a better result

bat585

 

[Newuser2006]

actually i have tried in the 2d-simulation both type of elements.since both also had a little difference in results from the experimental data or results i got,but when i've done the 3-d simulation comes the real massive difference between 2d and 3d and between simulation and experimental results.what do you suggest for both 2d and 3d?

 

[Bat585]

Are you sure youare using the adequate load in the 3D model?

If you are applying for example a pressure on your 2D model you apply it on the thickness you have defined in the section assignement, whereas you are applying on the real face f a 3D model...

If that's OK I don't have any idea...

Bat585

 

[Newuser2006]

i did not get your point,for example if in my 3d model iam applying a 10Mpa pressure on a circle of 20mm diameter,then what should be the load if i took in the 2d model,because of symmetry,the cross-section with a 20mm diameter and 1mm plane stress thickness?where is the difference.and thanks in forward

 

[corus]

If you're unsure of your loads then do a check on the total reaction forces produced by each model. These should equate to your total input force in all directions. To me it sounds sa if you're applying an out of plane load to a plane stress model and assuming you have a circle, but there is so little information in your question it's difficult to know what you're talking about. If you can, provide pictures.

corus

 

[Newuser2006]

where could i upload the pictures?
to simplify the question,we were talking about 3d and 2d.supposing i have a die with a circular cross section,and i want to apply a uniform pressure on a sheet of metal,that is above this die.so i will run one axisymmetric simulation,one 2d simulation and one 3d simulation.the pressure applied in experiment is 200bar.should it be the same pressure applied on the surface in all 3 cases.