I made a 3d model with BEAM elements and i dont't know how to interpretate de results (stress).
When i work with plate elements i use Vonmises Stress to see the stress results in MPa, but with beam i don't have this option and i don't know what option to choise.
It is the first time when i work with beam elements and i don't know if my structure will resist at the load (if the stress is lower than the material maximum value.)
Material: youngs modulus: 2.1e5 Mpa, poisson ratio 0.3.
If i worked with mm and the load in N, than the stress will be in MPa or N?
NX Nastran does not generate Von Mises stresses on beams as they are 1D elements. To get Von Mises stresses, you can use the View > Advanced Post > Beam Cross Section command and that generate Von Mises stresses on the fly using the beam cross section and NX Nastran results.
Please refer this posting for more information: https://community.plm.automation.siemens.com/t5/3D-Simulation-Femap-Forum/BEAM-Von-Mises-Stresses-in...
It might be easier for you to use the max/min combined stresses instead of VM. These are output vectors 3164-3167. You should be right with your second question, N + mm = N/mm^2 or MPa output units. I will refer you to Table 2-3 on page 2-3 (pdf page 21/776) of the NX Nastran user guide, found here: ...\FEMAPv114\nastranhelp\pdf\User.pdf.
Author, Learning Femap