property SOL_ORTH for solid elements

Maxime Pouliquen_20812

Hello,

I am trying to run a simulation of impact on a composite plate. I am using solid elements for the plies. For the material model, I am using law25 (COMPSH) with property 6 (SOL_ORTH). However, when I run little tensile tests on a single element, I can't seem to find the right modulus.

Here are the material data I used :

##--------------------------------------------------------------------------------------------------
## Material Law No 25. COMPOSITE SHELL
##--------------------------------------------------------------------------------------------------
/MAT/COMPSH/1
composite                                                                                           
1.58000000000000E-06
               112.0                 8.0                0.28         1                           8.0
                 4.5               2.857                 4.5                                        
                                                                                                    
                                                                                
                                                                                                    
1.00000000000000E+30                                                                                
                                                                                
1.00000000000000E+30                                                                                
                                                                                
1.00000000000000E+30                                                                                
                                                                                
1.00000000000000E+30                                                                                
                                                                                
1.00000000000000E+30                                                                                
                                                                                
                                                            
And here are my options used for the property:

##--------------------------------------------------------------------------------------------------
## Orthotropic Solid Property Set (pid 6)
##--------------------------------------------------------------------------------------------------
/PROP/SOL_ORTH/1
composite                                                                                           
        24                                                                     2                    
                                                            
                                                                               3          
                45.0
                                       1

 

I chose Ip = 3 and i am changing the value of Psi to get the correct orientation.
For Psi = 0 deg or Psi = 90 deg, i get modulus close to E11 and E22. However for Psi = 45 deg and Psi = -45 deg, i get 2 different modulus and they are not close to the shear modulus i entered.

Can anyone help me with this issue ?

Thanks in advance,
Maxime

Simon Križnik

Hi,

 

Ishell/Isolid=QEPH/HEPH=24 is not recommended for orthotropic materials because the physical hourglass stabilization forces are computed based on isotropic assumptions.

 

Instead, use fully integrated elements Isolid=14 or 17.

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Maxime Pouliquen_20812

Hello Simon,

 

That did indeed solve the issue!

 

Thank you very much.

 

Maxime