• Registered: 2024-11-20
  • Posts: 9

Topic: Questions regarding section 2.2.4 of ATENA troubleshooting

I want to model a beam with UHPFRC concrete using the user-defined material (2.2.4 I want to use the user-defined stress-strain law of concrete to replace that used in ATENA program. How can I do it?) in ATENA’s troubleshooting section, following the tutorial. I have a few questions:

1. According to ATENA’s troubleshooting instructions, do I only need to apply the tensile part from the Excel file(http://www.cervenka.cz/assets/downloads/Atena/HordijkUser.xls .)? Is there no need to make any changes in the compressive tab or Tensile strength reduction tab?

2. In Excel (http://www.cervenka.cz/assets/downloads/Atena/HordijkUser.xls .), do I need to enter the strain column myself according to the uniaxial tensile stress–strain curve?

3. In the diagram I will attach, the uniaxial tensile stress–strain curve has three phases — linear, strain hardening, and strain softening. How should I enter this into Excel(http://www.cervenka.cz/assets/downloads/Atena/HordijkUser.xls .), and how should I model it overall?

I would appreciate answers in the same order as my questions. Thank you very much.

Quote Post 1

  • Registered: 2019-10-24
  • Posts: 13

Re: Questions regarding section 2.2.4 of ATENA troubleshooting

I will try to answer your questions:
1. Hordijks law excel sheet is dedicated just to tension function. This function might cover strain hardening and softening but not the initial part of diagram that depends on E and ft. So yes you need to adjust the material parameters in other tabs accordingly. Regarding the tensile and compressive reduction, please check the ATENA-Science-GiD_Tutorial_FRC.pdf for more guidance. It is explained on example in GiD but that is not important, the material definition is the same regardless of used preprocessor.

2. You can enter the values from your diagram, it just depends on how many values you have. ATENA will connect the values in between your point with linear function.

3. Please check figure in Theory manual in section 2.2.6 Variants of fracture plastic model where is shown tension function with strain hardening. You need to define the localization onset when you use hardening. When you use only softening the onset is 0 and the tension function just decreases immediately with increasing fracture strain.

Quote Post 2