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!

[xwpken]

Hello, sigma represents the stress tensor at quadrature points within the element, while sigma_average represents the average stress tensor obtained from sigma. For a 3D problem, the dimensions of these two variables are (num_cells, num_quad_points, 3, 3) and (num_cells, 3, 3) respectively.

In the latest commit, we have added code to calculate the Von Mises stress vm_stress from sigma_average, and its dimensions are (num_cells,). It has been saved to the VTU file using the function save_sol . You can enable the data array vm_stress in ParaView to check it.

[peps212]

Thank you so much I really appreciate the help. One last question:

def get_surface_maps(self): def surface_map(u, x): return np.array([0., 0., 100.]) return [surface_map]

The value of the force applied, which in the demo is 100, is that in Newton?