Ok at first I would select a regular meshing for the structural areas.
In order to get the stresses exactly in the middle of the beam, you need the element edges to be vertical. So I would create a “dummy” beam (SLN) with no cross section at the position to be examined. (Another option is to divide the structural areas in the middle into two SARs)
In the programm Graphic you can now only select the FE-Elements in the middle of the beam with the “BOX” command. In a next step you can investigate the element-stresses. You have to keep in mind, that these QUAD-stresses are in the middle, at the top or at the bottom of the QUAD-Element.
Also, you need to consider the element size. The smaller the edge length of the QUAD elements, the finer the result.
test_3_Fix2BS_0612222.dwg (91.0 KB)
test_3_Fix2BS_0612222.sofistik (55.5 KB)
test_3_Fix2BS_0612222.gra (1010 Bytes)