Question about stresses for Linear_Elasticity demo

[peps212]

Hi, I noticed there was a recent commit made by @xwpken to the Linear_Elasticity demo that implemented post-processing for stresses in the beam. I'm just confused on how to interpret the data that has been computed at the end of the script (Sigma and sigma_average). I don't think they get saved into the VTU file, so I can't use Paraview to display it.

Could anyone help me out on how I can visualise them? Thank you!