I checked a simple tube with variable cross section for bending .
hand calculation states a max. stress of 312 MPa. the simulation show a max. stress of 1100 MPa.
the high stress is a "hot spot" format. if I refine the mesh, the stress result will go higher. in fact , a very coarse mesh gives closer results to reality.
how do I tackle these "hot spots"? it makes the whole simulation useless.
this is the model. a remote load that creates bending at the top of the tube & fixed constrain at the bottom.
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I would not ignore the area showing as red. The grooved section is an obvious stress raiser. Did you use a stress concentration factor when doing the calculations manually? Using a coarse mesh will cause the FEA simulation to overlook small irregularities.
And by the way, a singularity occurs where you have a corner sharp corner that comes to a point. From what I can see you don't have that situation.Derek, I didn't used correction factor in my calculation.
the high stress volume will remain even if I fillet all sharp edges to the max.
you recommend not to ignore these areas, how should I interpret this high stress result? it's 3 times higher than manual calculation .
should I assume that the part will deform or remain below the Yield point (350 MPa)?
Hello Paul,
Do you have an engineering background? If so, may I suggest you grab out the old text books and revise stress concentration. It seems to be the issue here. I am saying I would not ignore the high stresses. You are the designer and must take responsibility for how the design is altered to ensure that it avoids the problems the FEA has highlighted if you conclude they are correct. Sorry mate. Cannot help you much more.Paul,
Could you plot a mesh and geometry image? This could help to find the better way to deal with this singularity. It seems to be a result from the narrow channel in your model.
Best regards,
Eduardo Camargo