How modify Engineering Constants for using subroutine in ABAQUS

[Zilan]

Hello,

I am a new user of subroutine in ABAQUS. I am wondering if anyone knows how to modify the engineering constants such as E11, E22 and G12 for an orthotropic materials using subroutine in ABAQUS.

I found an example at the end of ABAQUS User Subroutine Reference Manual 1.1.45. It introduces how to modify the elastic modulus of an isotropic material, using one field variable.

I try to follow the example. First create an material matrix with engineering constants and 2 field variables as follow (I omit the other constants by assuming they would not change and only list E1 and E2):
E1 E2 … Field1 Field2
700000 400000 … 0 0
700000 400000 … 0.005 0.01
600000 350000 … 0.01 0.02
500000 300000 … 0.015 0.03
400000 200000 … 0.02 0.04

Where Field1 and Filed2 stores the strains in 2 directions. I hope ABAQUS could interpolates E1 and E2 through the values provided by Field1 and Field2. I also attach the subroutine file with the question.

However, it does not work because in the subroutine, those field variables are not associate with the engineering constants respectively, such as Field1 corresponding to E1 and Field2 corresponding to E2.

Does any one have a method to associate them together or do you have other ways to achieve the degradation of the moduli with increase of strains.

Thanks a lot.

Zilan

 

[akabarten]

Hi Zilan,

What about following material definition:

...
**
**    E1,      E2,         FV1,  FV2
 7.0e+05, 4.0e+05, ... , 0.000, 0.00
 7.0e+05, 4.0e+05, ... , 0.000, 0.01
 7.0e+05, 3.5e+05, ... , 0.000, 0.02
 7.0e+05, 3.0e+05, ... , 0.000, 0.03
 7.0e+05, 2.0e+05, ... , 0.000, 0.04
**    E1,      E2,         FV1,  FV2
 7.0e+05, 4.0e+05, ... , 0.005, 0.00
 7.0e+05, 4.0e+05, ... , 0.005, 0.01
 7.0e+05, 3.5e+05, ... , 0.005, 0.02
 7.0e+05, 3.0e+05, ... , 0.005, 0.03
 7.0e+05, 2.0e+05, ... , 0.005, 0.04
**    E1,      E2,         FV1,  FV2
 6.0e+05, 4.0e+05, ... , 0.010, 0.00
 6.0e+05, 4.0e+05, ... , 0.010, 0.01
 6.0e+05, 3.5e+05, ... , 0.010, 0.02
 6.0e+05, 3.0e+05, ... , 0.010, 0.03
 6.0e+05, 2.0e+05, ... , 0.010, 0.04
**    E1,      E2,         FV1,  FV2
 5.0e+05, 4.0e+05, ... , 0.015, 0.00
 5.0e+05, 4.0e+05, ... , 0.015, 0.01
 5.0e+05, 3.5e+05, ... , 0.015, 0.02
 5.0e+05, 3.0e+05, ... , 0.015, 0.03
 5.0e+05, 2.0e+05, ... , 0.015, 0.04
**    E1,      E2,         FV1,  FV2
 4.0e+05, 4.0e+05, ... , 0.020, 0.00
 4.0e+05, 4.0e+05, ... , 0.020, 0.01
 4.0e+05, 3.5e+05, ... , 0.020, 0.02
 4.0e+05, 3.0e+05, ... , 0.020, 0.03
 4.0e+05, 2.0e+05, ... , 0.020, 0.04
**
...

I did not test it, please let me know does it work for you.

Regards,
Bartosz

 

[Zilan]

Hello Bartosz,

Thank you very much for your reply.

I tried on one element model. The material model you suggested does not work as well.

Right now, I am trying to learn to use UMAT in ABAQUS following the example provided in ABAQUS Manual now to improve my model.

Thanks all the same.

Zilan