[CIG-SHORT] defining fault_edge nodes

Brad Aagaard baagaard at usgs.gov
Mon Jul 2 11:01:58 PDT 2018


Please see the response I sent on Friday.

http://lists.geodynamics.org/pipermail/cig-short/2018-June/003207.html

Regards,
Brad




On 7/2/18 9:05 AM, Niloufar Abolfathian wrote:
> Hi,
> 
> My question is about how the cell numbers ‘topology/cells’ or [icells] 
> are correlated with the vertex coordinates.
> I know what ‘geometry/vertices’ and
> ‘topology/cells’ are showing but I am not sure how the vertex coordinate 
> of each numbered vertex in ‘topology/cells’ is.
> For example: in 3d hexagonal case I have  vertices 
> 0,1,2,3,122,123,121,120 for a cell. Is the cooridnates of vertex 0, the 
> first column of ‘geometry/vertices’ and so on?
> 
> Thanks,
> Niloufar
> 
> On Sat, Jun 30, 2018 at 2:52 PM, Charles Williams <willic3 at gmail.com 
> <mailto:willic3 at gmail.com>> wrote:
> 
>     Dear Niloufar,
> 
>     If I’m understanding your question correctly, you need the
>     ‘geometry/vertices’ field, which gives you the vertex coordinates,
>     and you need the ‘topology/cells’ field, which gives you the
>     vertices associated with each cell.  If you are filtering your
>     results to the cell center, the cell center associated with each
>     cell will just be the average of the vertex coordinates for the
>     cell.  Remember that all indices are zero-based (rather than
>     one-based as in Matlab).
> 
>     Cheers,
>     Charles
> 
> 
>>     On 30/06/2018, at 10:29 AM, Niloufar Abolfathian
>>     <niloufar.abolfathian at gmail.com
>>     <mailto:niloufar.abolfathian at gmail.com>> wrote:
>>
>>     Hi,
>>
>>     I had another question regarding reading the output files. I am
>>     using matlab for reading the h5 files and further plottings.
>>     For reading stress and strain related to each material I do have
>>     the stress/strain regarding each gird cell plus the topology
>>     information (only number of vertices not the geometrical values).
>>     I could not figure out how to relate the topology cells with the
>>     geometrical vertices.
>>
>>     Thanks,
>>     Niloufar
>>
>>
>>     On Thu, Jun 21, 2018 at 7:14 PM, Brad Aagaard <baagaard at usgs.gov
>>     <mailto:baagaard at usgs.gov>> wrote:
>>
>>         On 6/21/18 5:50 PM, Niloufar Abolfathian wrote:
>>
>>             Thanks, Brad. By my second question, I mean in cases where
>>             the fault is extended to the external boundaries, and we
>>             want to set boundary conditions on these surfaces(external
>>             boundaries), fault nodes should be all excluded. Is this
>>             statement right?
>>
>>
>>         Yes, that is correct.
>>
>>
>>
>>
>>             On Thu, Jun 21, 2018 at 5:40 PM, Brad Aagaard
>>             <baagaard at usgs.gov <mailto:baagaard at usgs.gov>
>>             <mailto:baagaard at usgs.gov <mailto:baagaard at usgs.gov>>> wrote:
>>
>>                 On 6/21/18 12:38 PM, Niloufar Abolfathian wrote:
>>
>>                     Hi,
>>
>>                     I am modeling a 3D vertical fault in an upper
>>             crust, lying on a
>>                     lower crust. It is as your 3d/hex example instead
>>             of that the
>>                     fault is only located in the upper crust.  I set
>>             up the nodes
>>                     related to the fault and fault_edge. From my
>>             meshing and node
>>                     selection the fault should only be located in the
>>             upper crust,
>>                     but after running the model the fault is extended
>>             below the
>>                     upper crust. I guess it may be due to the
>>             selection of fault and
>>                     fault_edge nodes. Hope you can help me with this
>>             issue.
>>
>>                     Question: Should the fault_edge nodes be also
>>             included in fault
>>                     nodes? (I suppose the answer is yes, due to the
>>             figure 6.4 in
>>                     the manual.)
>>                     I tried excluding fault_edge nodes from the fault
>>             but then the
>>                     model will not be converged.
>>
>>
>>                 Yes. The fault edge nodes are included in the fault nodes.
>>
>>                 The edge nodes are any buried edges of the fault. That
>>             is, any nodes
>>                 on edges that are not on the external domain boundary
>>             should be
>>                 included in the fault edges.
>>
>>                     I have another question. In the example 3d/hex
>>             model, if we want
>>                     to define a boundary condition on y_neg/y_pos
>>             , the fault nodes
>>                     be excluded az z_neg, right?
>>
>>
>>                 I don't understand this question.
>>
>>                 Regards,
>>                 Brad
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> 
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