Abaqus FEA: What do e11, e22 and e33 stand for?

[ramzerimar]

I'm new to Abaqus and FEA in general, but my professor asked the class to do a simple analysis on a beam using Abaqus, just to introduce us into FEA methods. I've managed to do almost everything he asked for, but I'm confused about some notations when I get the results. I understand that s11, s22 and s33 are the stress components in the X, Y and Z directions, but what about e11, e22 and e33 - and u11, u22 and u33, by the way?

 

[Mech_Engineer]

I am not an Abaqus user, but I think e11, e22, and e33 refer to the volumetric strain terms. Not sure about the u11, u22, u33 terms, maybe a displacement tensor?