laminate composite, bricks & MAT9

[Cdz]

Hi there!
I'm trying to model a laminate composite by means of 1 layer of bricks and using a MAT9 card for this. The question is: Gij terms point to Ex,Ey,Ez,Gxy,Gyz,Gxz and the poisson's ratios of the entire laminate. I think Ex, Ey, Gxy and Nuxy can be obtained using the classical laminate theory for 2D, but how about the other terms?
I think Ez can be estimated considering the laminate like serial springs. Does anyone know where can I find something about this?
The laminate is made of 12 layers, fabric and tape and the known constants are E1,E2,N12 and G12.
Thanks!

 

[fkmeyers]

If you are using MSC they should have a MATORT dedicated to 3d orthotropic materials. For NEi Nastran use MAT12. See MSC Linear manual materials chapter for info on MAT9 setup for orthotropic materials.

 

[Cdz]

many thanks fkmeyers for your answer, the model will run on Nastran 2001 and the solution is gonna be 101. The MATORT is only for sol 600. The linear statics book gives the expresions for Gij in terms of the elastic constants for the entire laminate, the problem remains, is there a way to estimate this elastic constants? Does anyone know about a laminate theory which gives us a out-of-the-plane elastic constants?
thanks!

 

[SWComposites]

Cdz -

see my replies here thread327-136351

also, using one liniar solid element thru the lamiante thickness is a very bad idea if you have any bending loads/deformation on your structure. In general, solid elements are very poor in bending. What are you trying to model and what results are you trying to obtain?

Steve

 

[Cdz]

Hi
Im trying to modelate a single lap shear composite adhesive union, for several reasons the composite is gonna be modeled with bricks and also the adhesive. The material is AS4/8552 fabric and tape and the stacking sequence is:
Fabric(+-45)
Fabric(+-45)
Tape (0)
Tape (0)
Fabric (0/90)
Fabric(+-45)
Symetric
Can I use the recomendations given in those post?