Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
3D meshing
Posted 29.08.2011, 11:00 GMT-4 Geometry, Mesh, Results & Visualization Version 4.0 4 Replies
Please login with a confirmed email address before reporting spam
I have a 3D model like the attachment.
As for all the fractures and faults inside (in the centre of) the block, I did a triangular meshing and as for the block itself, I did a tetrahedral mesh.
I received the following error message upon a run:
Failed to find consistent initial values.
Singular matrix
There are 9642 void equations (empty rows in matrix) for the variable mod1.p
and similarly for the degrees of freedom (empty columns in matrix)
I wonder if it has something to do with the 3D meshing, as if the mesh is not spreading all over the block inself from outside to inside?
Appreciate your help!!
regards
Liwah
Attachments:
Please login with a confirmed email address before reporting spam
Well from a first view on could believe that your mesh is only a boundary mesh without any volume elements, or that your geometry is such that the domains and boundaries are not well defines. Perhaps go through the domains, one by one (Selection List) and then the same for the boundaries. Check also the mesh statistics
If the mesh seems OK, it's related to a poor definition of the boundary conditions, something must be missing
--
Good luck
Ivar
Please login with a confirmed email address before reporting spam
many thanks for your inputs :) may I know where i.e user interface to define volume elements? I found 'volume of elements and mesh' in help search but I have no ideas where in 'model builder' should I work on that?
many thanks again for your time and great help!
regards
Liwah
Hi
Well from a first view on could believe that your mesh is only a boundary mesh without any volume elements, or that your geometry is such that the domains and boundaries are not well defines. Perhaps go through the domains, one by one (Selection List) and then the same for the boundaries. Check also the mesh statistics
If the mesh seems OK, it's related to a poor definition of the boundary conditions, something must be missing
--
Good luck
Ivar
Please login with a confirmed email address before reporting spam
if you are in 3D the default is volume "tetrahedral" (onto which you have by default 2nd order shape functions which gives you more or less the equivalent to hex type in older software)
You need to apply manually surface mesh (as seed meshes), but normally a default "remaining" Tetrahedral remains as last node. Mostly I start by using the default mesher, only when it fails then I need to work "manually"
Note v4.0 was rather weak in functionality, update to the latest version you will be less frustrated ;)
--
Good luck
Ivar
Please login with a confirmed email address before reporting spam
you are right, v4.0 is kinda driving me crazy.
But anyway, I am still trying my luck with the mesh, I still cant do the volumetric mesh, as if there aint a way to do it... I tried swept, scale and distribution, to no avail... :(
regards
Liwah