Dear Wen,

Yes, the mesh_level_set object performs most of the job : on each
element cut by the crack, a certain number of intersection points are
computed (the density of computed point depends on the curvature of the
level set). Then Qhull is called to obtain a sub-mesh of the element
conformal to the crack (or any set of level-sets). Some verifications
are performed : if the obtained mesh is not conformal to the crack, more
intersection points are computed.

Additionally, the sub_mesh is stored by the object mesh_level_set and
can be extracted (cut_mesh() method). If there is a lot of cut elements,
it can be a bit expensive in term of memory (but not so much in
practice) but it is necessary for post-treatment : it allows  to
interpolate the solution on a cut-mesh before drawing it.

Yves.


Le 23/11/2016 à 16:44, Wen Jiang a écrit :
> Hi,
>
> I am interested in how getfem++ uses the qhull library to do the
> triangulation of the mesh which is cut by a level set function. I have
> two questions,
>
> 1. In 3D, the crack front could terminate within the element and it is
> easy to know which element contains the crack front based on the level
> set functions. But it is not clear to me how to use qhull in
> conjunction with level set function to do the sub-triangulation. Does
> getfem need to find the points along the crack front somehow from the
> level set function?  
>
> 2. Getfem can integrate quantities along the interface (3D is surface,
> 2D is line). Where does getfem store these surfaces/lines that are
> generated from triangulation by qhull?
>
> Thanks,
> Wen
>
>
> _______________________________________________
> Getfem-users mailing list
> [email protected]
> https://mail.gna.org/listinfo/getfem-users


-- 

  Yves Renard ([email protected])       tel : (33) 04.72.43.87.08
  Pole de Mathematiques, INSA-Lyon             fax : (33) 04.72.43.85.29
  20, rue Albert Einstein
  69621 Villeurbanne Cedex, FRANCE
  http://math.univ-lyon1.fr/~renard

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