Difference in Von Mises Results Between Beam Model and 3D Model

[Jeremy1989]

Hi,

I am trying to study the difference between the static structural results of a 3D model and Beam model. I used a simple I beam example whereby one end of the beam is fixed support and the other end is a load downwards 100kN. When I compared the max von mises stress between both models, the Beam model reported significantly lower VM stress compared with 3D model. I enabled 'Beam Section Results' for the beam model to view the VM stress. Appreciate if someone can enlighten me on the reason for such difference? I have included pictures of the results for beam model and 3D model respectively as reference. Thank you in advance.

 

[SWComposites]

What is the difference in end deflection?
Please compare X direction stresses.
Are you sure the beam model has the same section properties as the 3D model?

 

[Stick.]

In addition to what SWComposites suggested, make sure you're not looking at any max stresses that are the result of singularities/boundary condition artifacts, as looks to be the case with the max stress label on your 3D model. While it's hard to tell from your pictures, the stress values a little bit away from the fixed end and also at the beam midpoint look to be fairly similar for the two cases. Also, make sure you've done a hand calc to verify your model and give you an idea of the expected ballpark for your stress results.