• Registered: 2013-02-05
  • Posts: 4

Topic: ATENA 3D v 4.2.7.5844

Hi, I am very new ATENA 3D (v 4.2.7.5844) user. I just read ATENA Program Documentation Part 1  Theory published on published on March 14, 2012, which staes that this software can be used for ultra high performance fibre reinforced concrete (UHPFRC).
As I am very new user of ATENA. I have few querries:

(1) Is the version (which i am using) applicable to (UHPFRC) and High Strength Concrete? If yes, then
                      (i) which material type should be selected as the words "The CC3DNONLINCEMENTITIOUS2SHCC is suitable for fibre reinforced concrete, such as SHCC (Strain Hardening Cementitious Composites) and HPFRCC or UHPFRC (high and ultrahigh performance fiber reinforced concrete) materials. The theory of this material model is identical to those described in Sections 2.2.1 - 2.2.6. The tensile softening regime (Fig.2-32) and the shear retention factor (Eq. (2.94)) are modified based on the model, proposed in KABELE, P. (2002). This model is based on a
notion of a representative volume element (RVE), which contains distributed multiple cracks (hardening)
as well as localized cracks (softening) – see Fig. 2-31." This sentense published in "Program Documentation Part 1 Theory " are not understandable to me.

                     (ii) Is the version 4.2.7.5844 can be used for the dynamic analysis of (UHPFRC) and High Strength Concrete.

Quote Post 1

  • dpryl
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  • Registered: 2007-07-13
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Re: ATENA 3D v 4.2.7.5844

Hello, 4.2.7 is a few years old already, please make sure you are using the latest version you have. If you can not find a later installation CD, please download the upgrade installer corresponding to the expiration date of your maintenance (i.e., the latest version released before maintenance expiration) from our web. Or write us your ATENA User ID (WR) and we can send you the latest version which can be used with your license.

If you find out the normal CC3DNonlinearCementitious2 (NLCem2) material model can not capture the response of your material precisely enough, use CC3DNonlinearCementitious2User. the -SHCC material model is essentially identical to -User, except for the way how shear repose is defined.

If you decide to use the NLCem2User (or -SHCC) material model, please read ATENA Troubleshooting Manual, section "2.1.9 I want to use the user-defined stress-strain law of concrete to replace that used in ATENA program. How can I do it?" before you start.

However, in many cases, the normal NLCem2 material model (or the SBETA material in 2D) works well enough even for High Strength or Fibre Reinforced concretes. The simplest modelling is to generate the material properties for the concrete without fibres and increase the fracture energy (Gf), typically 100-1000 times.

dpryl's Website

Quote Post 2

  • Registered: 2013-02-05
  • Posts: 4

Re: ATENA 3D v 4.2.7.5844

Thanks for your kind help. I am very much clear from your answer and very soon, I will update you about my experience of using CC3DNonlinearCementitious2 (NLCem2) and CC3DNonlinearCementitious2Use.

I have also gone through the section "2.1.9 I want to use the user-defined stress-strain law of concrete to replace that used in ATENA program. How can I do it?" and downloaded the excel sheet.

I have to ask further question.

I am making two beams made up FRC (without any reinforcement) to observe the bhaviour of FRC in tension. Out of the two, one beam will be tested under static load (with a load increment of 0.01kN/sec) and the result of the failure load will be used for the cyclic loading test.

For the cyclic loading test, I will use upper load limit as 60% of the static failure load and lower load limit as 10% of the static failure load. I have gone through the your reply post published on "2009-05-20 13:45:03" about "HOW TO APPLY CYCLIC LOAD IN ATENA????", which states the input of cyclic load in terms of prescribed deformation.
I am a bit confused about my case in which i am applying load AS UPPER and LOWER limit instead of deformation.

Please suggest me modelling technique of the cyclic load

Quote Post 3

  • dpryl
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  • Posts: 1,107

Re: ATENA 3D v 4.2.7.5844

In case you have prescribed force levels in each cycle, use force loading (and unloading), with a monitor for EXTERNAL FORCES (instead of reaction) at the loading point. In other aspects, you can follow the recommendations for displacement-controlled cyclic loading.

However, if I understand correctly that you cycle the load between 10% and 60% of the static max. load level, it is likely there are going to be MANY cycles to failure (e.g., milions). Then, it is of course not feasible to model the time history explicitly (milions of load steps!). I can recommend to look at the NLCem2Fatigue material model (see the corresponding Help texts in the ATENA-GiD Material and Interval Data dialogs), however, please note 1. this material is only available from ATENA Science (through the ATENA-GiD user interface), not from ATENA Engineering (2D nor 3D) and 2. only tensile fatigue damage can be taken into account this way and 3. the NLCem2Fatigue material is an extension of the NLCem2 material, NOT NLCem2User, which can limit your FRC modelling. 4. Please also note it is not known at all if the model is suitable fatigue damage in FRC - I guess the fibre-concrete bond can play a very significant role under cyclic loading, and the model can not explicitly include this effect.

dpryl's Website

Quote Post 4

  • Registered: 2013-02-05
  • Posts: 4

Re: ATENA 3D v 4.2.7.5844

Thanks a lot for your kind reply. I have another problem now. I modelled different fibre reinforced concrete (FRC) beams using "CC3DNLCementicious 2" material model. FRC beams have different compressive strength values. The results of simulated peak loads are quite satisfactory and much close to the experimental failure loads (this indicates that my model is OK). The problem is with deflection corresponding to the peak load values. Deflection values of all FRC beams are constant as 0.187 mm which is impossible that all beams attain same deflection. Other problem is that this value of deflection is significantly lesser than the deflection results obtained through experiment.
I already read Troubleshooting manual, but I didn't find anything related. Please help me urgently.

Quote Post 5

  • dpryl
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Re: ATENA 3D v 4.2.7.5844

If you have already followed the suggestions in ATENA Troubleshooting, 2.1.20 My analysis results do not match the experiment/expectations. How can I improve my model?, please send us one or 2 of your models along with a description what you are modelling plus a sketch and/or photo. Please do not forget to include your ATENA User ID (WR) in your email.

dpryl's Website

Quote Post 6

  • Registered: 2013-02-05
  • Posts: 4

Re: ATENA 3D v 4.2.7.5844

i sent you two models at cervenka@cervenka.cz. please check.....thank you

Quote Post 7