simple Beam in COSMOSWorks!?!

[Scarpafico]

Hi @ all,

I wanted to compare an easy beam calculation with a COSMOSWorks Analysis. The problem is, the stresses from the FEA are twice as high as the theoretical calculation.

I have a beam with a hollow rectangle cross-section ( 600mm wide,250mm high, 5500mm long and 3mm thick). Two boundaries at the end, a normal-force at the middle/center plane (800N) and a UDL (q=0.047N/mm) for the gravety (see beam picture).

For the beam calculation I used basic stuff like bending moment in the middle of the beam, moment of intertia...and get arround 2MPa as a maximum in the middle of the beam (the calculation should be all right).

With COSMOS I get 7MPa (von mises) in the middle of the top surface! (see picture). Does any body know where the problem could be? Is it because I compare normal stress with Von-Mises Stress? I think the difference shouldn't be so huge...

I am looking forward to any help!!! I really tried anything I know...

Cheers,
Christian