I have been regularly using the elastic tensor package. Normally I am perfectly content with this package, but lately I have been getting into material systems where the curvature of the stress-strain relationships tend to not be well behaved. Is there any way to make modifications to diff_fit such that we can take into account how well the curvature of the stress-strains were fit?
In some cases I end up with non-symmetric lines about the the zero-strain point, to me this points to some numerical error, but it would be nice to be able to detect this numerically rather than having to go through all graphs myself. (See below, left is my shear variances of lagrange strain element 4, i.e. shear of x-z and y-z). I’m not sure if anyone has ever plotted these, but have you ever experienced non symmetric artifacts like this (my personal opinion is it is due to not maintaining orthogonality on the structure, they varied by about 1-2 degrees)?