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Modeling Reinforced Concrete Element in Abaqus Standard

hello everyone,

I am trying to model a concrete element subjected to static load using Abaqus Standard. For concrete, I am using Concrete Damaged Plasticity and beam elements for my reinforcement. I am embedding my reinforcement into the concrete (host elements).

Since I started, I faced several issues. They are overconstraint, numerical singularity and negative eigen values. I managed to resolve both of them. However, the behavior from my model is nowhere near the experimental data that I have. It seems that the model is excessively stiff.

I have checked my material model's stress-strain, tried finer elements but it does not help. I am really lost as in why the model is stiff and I am not getting results near the experimental data. 

Does anyone have experienced modeling RC elements subjected to static loads in Abaqus Standard? I really hope that you can offer me some advice. I really appreciate that.

Thank you and Regards,
Joseph

Comments

amar123's picture

I am trying to use concrete damaged plasticity for RC beam. However,
Abaqus is not accepting data provided with the concrete compression damage and
concrete tension damage. I receive the following messages, whatsoever care I
take to furnish the data.

* DURING THE CONVERSION FROM CRUSHING TO PLASTIC STRAIN ABAQUS FOUND NEGATIVE
AND/ OR DECREASING VALUE OF PLASTIC STRAIN. VERIFY THAT THE DEGRADATION DATA
UNDER *CONCRETE COMPRESSION DAMAGE IS CORRECT.
*DURING THE CONVERSION FROM CRACKING TO PLASTIC STRAIN ABAQUS FOUND NEGATIVE
AND/ OR DECREASING VALUE OF PLASTIC STRAIN. VERIFY THAT THE DEGRADATION DATA
UNDER *CONCRETE TENSION DAMAGE IS CORRECT.

 I am furnishing the following set of data.

*Elastic
 19.7, 0.19
*Concrete Damaged Plasticity
38.,     1.,   1.12, 0.6666,     0.
*Concrete Compression Hardening
     15.,          0.
 20.1978, 7.47307e-05
 30.0006, 9.88479e-05
 40.3038, 0.000154123
 50.0077, 0.000761538
 40.2361,  0.00255756
 20.2361,  0.00567543
*Concrete Tension Stiffening
  1.99893,          0.
    2.842,   3.333e-05
  1.86981, 0.000160427
 0.862723, 0.000279763
 0.226254, 0.000684593
 0.056576,  0.00108673
*Concrete Compression Damage
       0.,          0.
       0., 7.47307e-05
       0., 9.88479e-05
       0., 0.000154123
       0., 0.000761538
 0.195402,  0.00255756
 0.596382,  0.00567543
*Concrete Tension Damage
       0.,          0.
       0.,   3.333e-05
 0.406411, 0.000160427
  0.69638, 0.000279763
 0.920389, 0.000684593
 0.980093,  0.00108673

 

Any help will be highly appreciated.

Thanks.

balaji227's picture

hi amar now that i'm working on damage modelling.  ..even i'm fascing the same problem can you please let me know where i have went wrong.

even i'm encountering with the error

* DURING THE CONVERSION FROM CRUSHING TO PLASTIC STRAIN ABAQUS FOUND NEGATIVE
AND/ OR DECREASING VALUE OF PLASTIC STRAIN. VERIFY THAT THE DEGRADATION DATA
UNDER *CONCRETE COMPRESSION DAMAGE IS CORRECT.
*DURING THE CONVERSION FROM CRACKING TO PLASTIC STRAIN ABAQUS FOUND NEGATIVE
AND/ OR DECREASING VALUE OF PLASTIC STRAIN. VERIFY THAT THE DEGRADATION DATA
UNDER *CONCRETE TENSION DAMAGE IS CORRECT. 

 

 

 

concrete material

*MATERIAL, NAME=Concret

*DENSITY
2.5650E-09
*ELASTIC,TYPE=ISOTROPIC
20800.0, 0.175
*CONCRETE DAMAGED PLASTICITY
36.31
*CONCRETE COMPRESSION HARDENING
13.0, 0.000
24.1, 0.001

*CONCRETE TENSION STIFFENING, TYPE=DISPLACEMENT
2.9 ,0.0
1.94393 ,0.066185
1.30305 ,0.12286
0.873463 ,0.173427
0.5855 ,0.22019
0.392472 ,0.264718
0.263082 ,0.308088
0.176349 ,0.35105
0.11821 ,0.394138
0.0792388 ,0.437744
0.0531154 ,0.482165

*CONCRETE TENSION DAMAGE, TYPE=DISPLACEMENT
0.0 ,0.0
0.381217 ,0.066185
0.617107 ,0.12286
0.763072 ,0.173427
0.853393 ,0.22019
0.909282 ,0.264718
0.943865 ,0.308088
0.965265 ,0.35105
0.978506 ,0.394138
0.9867 ,0.437744
0.99177 ,0.482165

MATERIAL, NAME=Rebar_steel
***DENSITY7.85E-09
*ELASTIC, TYPE=ISOTROPIC
199000 ,0.3
*PLASTIC
220.0 ,0.0
320.0 ,0.2

 above is the data i have used

 

can you tell me how reinforcemnt concrete in abaqus program

please help me

binoddhakal's picture

Best way is to go through the cracking models of concrete and other models related to concrte given in the abaqus documentation. You have

* Rebar layer option with  * shell section ---for  reinforcement  in concrete.

 

 

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I’m trying to model a reinforced concrete beam using concrete
damage plasticity. I have conducted an experiment for both uniaxial tensile and
uniaixle compressive test.  I have used
ABAQUS concrete damage plasticity. I have derived both Tension stiffening and Compression
hardening parameter but I have a problem with concrete compression damage and
concrete tension damage. I don’t know how and what equations I should use and
how to derive the data.

I would really appreciate if anyone could help me.

 Regards

G

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