Can anyone explain out of plane (E33) Young's Modulus and how to get it?

[HarambeWasAnInsideJob]

Okay, lets assume I am trying to model a thin strip of carbon fiber weave sample for compression loading in FEA.
When creating my material, I have my E11 and E22 from my material testing. Since I am assuming the weave to be perfect, I am assuming E11 = E22.
Now, where do I get E33 (out of plane) value? I understand that it is essentially the epoxy/matrix... So does that mean the young's modulus of the epoxy = E33? Is the E33 even important??
Does the compressive modulus have anything to do with this?
Thank you so much!!

 

[SWComposites]

For in-plane loading analysis E33 is not important. Why are you modelling with 3D elements and not shell elements?

E33 is typically a bit higher than pure epoxy modulus. And it is not related to your fabric inplane moduli. For unidirectional tape E33 ~= E22.

 

[HarambeWasAnInsideJob]

Hmm. Well I am modeling with shell elements, but this is for my material definitions.

But what you said makes more sense; if I am only doing in plane linear static loading, then E33 should not matter (because everything will be in plane). That makes sense...

But just for kicks: my fabric is not unidirectional, it's weave. So E11 = E22. SO does that mean E33 would be the epoxy modulus or compressive modulus? That's where I am confused.

I keep seeing reports where people use the compressive modulus of some material for E33 for WEAVE composites.

 

[SWComposites]

there is no E33 input for shell elements.

 

[HarambeWasAnInsideJob]

Thank you SWcomposites for your response.. but when I create a new material in my FEA software it asks for E1,2 and 3. So you're saying ignore E3 since I'll be meshing with shell elements??

Any chance you could shed some light on the compressive modulus too? Is this a necessary value to have for FEA?

 

[SWComposites]

What software?
What FE code?
What specific element/property type?

Compressive modulus is typically used for buckling analyses.