Symmetric Constrains

[ksarita20]

hi ,


I am doing an analysis on a cylindrical object, where i am using only 1/4 of the part for analysis. So i am confused in specifying the constrains at the symetric surfaces. i am sure that the translational constrains should be free in the plane of symmetry, but what about the rotational constrains.


Can any one please explain me.


Thanks in advance


Sari

 

[ankarl]

The translational constraints should be fixed in the symmetry plane,
rotational doesn't matter if its a 3D model.
Mechanica only consider rotation in 2D-models as far as I remember (I only use 3D so I might not be right about 2D)



/Anders

 

[ksarita20]

hi ,


Is your sentence " The translational constraints should be fixed in the symmetry plane" same as mine " the translational constrains should be free in the plane of symmetry" OR am i wrong.


i have refered another forum which also said the same. so please clarify me.


thanks


Sari

 

[Luis Aguirre]

Sari,


Here is the way it works:


Translation in the cutting plane of symmetry should be set to free. The translation degree of freedom normal to the cutting plane should be fixed. The reason for this is that the material cannot cross through the plane of symmetry other wise will violate the compatibility stress and strain field which requires that the material is continuous ( no holes) and does not overlap.For the rotation degree of freedom you do the opposite of what you assigned to the translation.





Luis
Edited by: Luis Aguirre

 

[ksarita20]

yaaa thats what even i understood, may be i am wrong in the way i expressed it.


anyway thanks for clarifying.


Sari