[CIG-SHORT] Principal Stress Axes

[BOK10 at pitt.edu]

Thanks for the quick reply! One last thing. I just want to check that the
negative Sxx/Syy values are compression and the positive tension?

Bobby

> 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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