Hi,
We have like a banana shaped plastic part that is being pulled at its ends. The cross section is a T-shape.
I have been trying to find out what area is under tensile and what area under compression.
You would expect this to show up in any first- or third-principle plot, but the problem is that this differs A LOT.
When looking at first principle (tensile) it looks as if most of the part is under tension, whereas when I look at third principle most of the part seems to be under compression!
Of course this can't be.
Because our plastic has different strengths in compression and tensile, we never use Von Mises (because Von Mises assumes equal strength for tensile and compression).
So I might look at von Mises to know the exact position of the neutral axis (if this would be correct), but I need to know the exact magnitude of the tensile and compressive stress too, and this is now totally unclear (different height and position in first and third principle) .
In another test case where I just did some quick bending FEA, you'd expect the compressive and tensile area to be about symmetrical, but no compression shows up in the first principle plot, even though I chose a symmetrical tension scale.
Thanks in advance for the help!
We have like a banana shaped plastic part that is being pulled at its ends. The cross section is a T-shape.
I have been trying to find out what area is under tensile and what area under compression.
You would expect this to show up in any first- or third-principle plot, but the problem is that this differs A LOT.
When looking at first principle (tensile) it looks as if most of the part is under tension, whereas when I look at third principle most of the part seems to be under compression!
Of course this can't be.
Because our plastic has different strengths in compression and tensile, we never use Von Mises (because Von Mises assumes equal strength for tensile and compression).
So I might look at von Mises to know the exact position of the neutral axis (if this would be correct), but I need to know the exact magnitude of the tensile and compressive stress too, and this is now totally unclear (different height and position in first and third principle) .
In another test case where I just did some quick bending FEA, you'd expect the compressive and tensile area to be about symmetrical, but no compression shows up in the first principle plot, even though I chose a symmetrical tension scale.
Thanks in advance for the help!
