[SOLVED] Degré De Liberté / Degrees Of Freedom

mattia

Hi everybody!

Which is the easiest way to get the number of Degrees of Freedom related to a model? Is it possible with Salome-Meca? If one has to use Code_Aster, which is the command to use? I found the command NUME_DDL but I don't know if it's the right one.

Thanks,

mattia

I would like to explain better my problem:

1. Meshing a X-FEM model with Salomé-Meca, I noticed that the number of elements is higher than the number of nodes, which is clearly impossible. This is probably due to the fact that the X-FEM nodes are not taken in account. So, which is the size of the stiffness matrix?

2. With standard FEM, I can get the DOF by multiplying the number of DOF per element by the number of elements of my model. But what if I want only the unconstrained DOF?

Thanks,

ThomasDESOZA

Hi,

When running your calculation, in the .mess file, STAT_NON_LINE or any operator that produces a matrix, will display the size of the problem :

La matrice est de taille 9593 équations.


Mais elle contient:
   -  144890 termes non nuls si elle est symétrique (soit un taux de remplissage de   3.15e-01 %)
   -  280187 termes non nuls si elle n'est pas symétrique (soit un taux de remplissage de   3.04e-01 %)
Le nombre de termes non nuls est susceptible de varier si l'on utilise le contact en méthode continue

ou la méthode XFEM avec contact.

Note that the number of dofs is exact but the number of non zeros (nnz) may change during the calculation in some cases (contact for example).

TdS

mattia

Hi Thomas,

Thanks for your reply, I came to the same conclusion by checking the .mess file.

Regards,