Why is it that 1st principal stress vector's don't line up with 1st principal normal strain vector plots? I was always under the impression these should line up.
That doesn't help. I created a purely tensile simulation to better understand this but it has only left me more confused. I attached the simulation to this.
I thought about this further and I was incorrect in my earlier statement about element vs nodal values.
Based on Generalized Hooke's Law (http://www.engrasp.com/doc/etb/mod/stat1/hooke/hooke_help.html), the strain and stress may not line up if Poisson's ratio is a non-zero quantity. If you make nuxy in your material definition zero, the two vectors will line up.
I think figure 4 shows how all this gets derived. I guess the Poisson's ratio would have an impact on the angle. It just doesn't seem to make much sense to me because there is no compressive strain, only tensile.
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