Which version of SW are you using? We found a critical issue with the mesher in SW11 SP5 (see https://forum.solidworks.com/message/250006 ) that threw out unusable results, it may be you are seeing a result of the same problem in a different way?
Dave thank you very much for your answer.
I have got SW12 x64 SP4.0.
I have a look at the post you indecated to me.
however I don't think this is the same problem. I have made several trials with different models and different meshes and for each ones the results is not what we could expect.
futhermore the other graph (VonMises strain, displacement, P1,P2,P3 , etc) seems to be correct. Then it should indicate that this is not a mesh problem
I thinks the formula of Mohr Coulomb criteria, is not well calculated.
I have extract in excel the P1 en P3 values for the nodes located at one end of the rode (the shape is a disk). Following the solidworks equation, I have calculated the Mohr coulomb criteria. As i have the coordonnates of the nodes, I have also calculated the distance of each node from the center of the rod (ie. the radius).
I draw the Mohr Coulomb criteria against the radius:
like expected, the M-C criteria is proportional to the radius. SW don't show the same result!
This indicate that SW calculated well P1 and P3 but that the calcul of Mohr-Coulomb criteria is wrong?