Deflected cantilever beam stress, Ansys

[eveS]

I am a newcomer to FEM and Ansys, so forgive the possibly banal question:

I have modeled a cantilever beam with a vertical point load acting at the free end using Ansys (using a PLANE42 element) and am slightly confused about the resulting plot for stress in y direction (y being the axis pointing downwards) versus y coordinate in the central cross-section.

The stress is mostly approximately equal to zero (which makes sense) except near the top and bottom surface of the beam, where it jumps abruptly to, respectively, a high positive value, and a high negative value. How could this be explained?

 

[Unrest]

I think this is an artifact of the element formulation. I've seen a similar thing in another package. Maybe play with the keyopts or change to the 2nd order elements.

If the width of the high stress area gets thinner with mesh refinement then it wouldn't be confused with a real stress so nothing to worry about. As well as you would't expect any normal stress on the free edge.