Add the elastic strain tensor to the volume output

[NicoSchlw]

Hi,
I want to request to add the possibility of outputting the elastic strain tensor in the volume.

Rationale

The feature request is related to ongoing research questions regarding the decay of near-field terms and non-linear soil effects.

Description

If the implementation is too complicated, it would probably also be possible to write a post-processing script to compute the strain tensor from the stress tensor.

General information

• I have searched the issues of this repo and believe this is not a duplicate

Best regards,
Nico

[sebwolf-de]

Hi,
the feature is almost there:

SeisSol/src/ResultWriter/EnergyOutput.cpp

Lines 269 to 277 in 9235d25

	auto computeStrain = [&](int i, int j) {
	double strain = 0.0;
	const auto factor = -1.0 * (lambda) / (2.0 * mu * (3.0 * lambda + 2.0 * mu));
	if (i == j) {
	strain += factor * sumUniaxialStresses;
	}
	strain += 1.0 / (2.0 * mu) * getStress(i, j);
	return strain;
	};

, we would just need to add this to the volume output, probably in this function: https://github.com/SeisSol/SeisSol/blob/master/src/ResultWriter/WaveFieldWriter.cpp#L442

[sebwolf-de]

It is rather easy to do this in paraview as a post-processing
step.

1. Use easicube to sample the material model on a grid. Or even better, sample the material parameters onto the mesh, which you used for your simulation.
2. Use attached paraview (save as .pvsm) script to compute e_xz. Other strain components can be done analogously.
   paraview-strain.txt

[krenzland]

That works, but you have to keep in mind that this ignores the "group" property.