Question: ANSYS & Laminate Composite Plate

Laleh Fatahi's picture

Hi friends
I want to use ANSYS to find the maximum deflection of a laminate composite plate that is made of graphite epoxy .It has 100 mm width and 500 mm length.
The layup is [45(10),0(10)]  (20 Layers).
The plate is simply supported along all 4 edges and is subjected to a uniformly distributed transverse direction load p=10,000 N/m2.

The material properties of the layers are as below: 


[0]
[45]

Longitudinal Young's  Modulus(Gpa)
148
16.39

Transverse Young's  Modulus(Gpa)
9.65
16.39

Longitudinal Shear Modulus(Gpa)
4.55
38.19

Longitudinal Poisson's Ratio
0.3
0.801

according to the above properties I filled the layer properties of shell99 (or solid191).But when I want to solve it,and error occurs due to layer properties of 45 degree plies,I don't know why this error occurs?! I assumed that 45 degree layers are  transverse isotropic material(Is it true?) and with this assumption I've calculated complete material properties required for shell99...

Below is a captured image of the error window of ANSYS:

I appreciate any help

Laleh Fatahi

http://laleh.fatahi.googlepages.com

 


ramdas chennamsetti's picture

Check Major/Minor Poisson's ratio

R. Chennamsetti, Scientist, R&D Engineers, India

Check whether you are inputting major Poisson's ratio or minor ???

If the above error (in ANSYS) occurs, the diagonal elements of the stiffness matrix will become -ve.

You can assume the ply has transversely isotropic properties. For non-zero plies you need not calculate equivalent props. You have to mention layer number, orientation, thickness, material property number.

In material props list, you mention the properties of UD laminate only.

MP, EX,1,148e9

MP,EY,1,9.65e9

MP,EZ,1,9.65e9 ....etc. This material has a reference number '1'. For 45 degree plies mention the ply angle and material number as '1'

 


Laleh Fatahi's picture

Thanks Ramdas...

I followed your advice,and fortunately my problem was solved.Thanks alot.

Laleh Fatahi
http://laleh.fatahi.googlepages.com