[CIG-SHORT] Principal Stress Axes

[Brad Aagaard]

Bobby,

Your best option is to write out to HDF5 files and use a Python script 
to compute the principal stress axes. The PyLith binary includes the 
Python h5py module which makes reading HDF5 files trivial. You can add 
the principal stress values to the binary and then update the Xdmf file 
using pylith_genxdmf. This will allow you to load the principal stress 
values ParaView. See examples/2d/subduction/afterslip_tractions.py for 
an example of reading an HDF5 file using Python.

The stress coordinate system is the global XYZ coordinate system.

Brad

On 4/8/13 10:02 PM, BOK10 at pitt.edu wrote:
> Hi,
>
> I've been trying to take the stress output (Sxx, Syy, Sxy) and convert
> them to principal stress values and solve for the orientation of S1 in the
> global coordinate system. Is there a way to do this in Paraview? Also,
> does the stress output (vtk) write as a local system with the origin in
> the centroid of each cell with the x-axis parallel to the vector from the
> first node to the next, or is the vtk output based on cartesian x/y
> directions in my model? My model is a 2D model of strike-slip faults.
>
> I've been calculating the cell centers and exporting the cell data to
> excel to calculate the orientation of S1. This has been rather tedious
> considering the limitations of excel. Any insight in how to do this in
> Paraview, or if what I have been doing so far is on the right track would
> be greatly appreciated.
>
> Bobby
>
>
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