Problem with Stress Relaxation after cracking-solid65

- October 21, 2019 at 12:08 am
  
  zoiralli
  Subscriber
  
  Hello everyone,
  
  I am trying to work solid65 command for unreinforced UHPC. I have followed the suggestions in this discussion /forum/forums/topic/entering-non-linearity-in-workbench-for-concrete/?postbadges=true, but my results are not right. The commands which give more accurate results are the following:
  
  *SET,ELEM_TYPE_ID,1
  
  ET,ELEM_TYPE_ID,solid65
  
  KEYOPT,ELEM_TYPE_ID,1,0
  
  KEYOPT,ELEM_TYPE_ID,3,2
  
  KEYOPT,ELEM_TYPE_ID,5,0
  
  KEYOPT,ELEM_TYPE_ID,6,0
  
  KEYOPT,ELEM_TYPE_ID,7,1
  
  KEYOPT,ELEM_TYPE_ID,8,0
  
  and for concrete model:
  
  ET,MATID,SOLID65
  R,MATID,0,0,0,0,0,0
  RMORE,0,0,0,0,0
  
  MP,EX,MATID,48000
  MP,PRXY,MATID,0.18
  MPTEMP,MATID,0
  
  TB,CONCR,MATID,1,9
  TBTEMP,22
  TBDATA,1,0.2,0.8,15,120
  
  TB,MISO,MATID,1,3,0
  TBTEMP,22
  TBPT,,0.0035,120
  TBPT,,0.0025,108
  TBPT,,0.0015,72
  
  My main problem is how to input the stress relaxation factor (c9) as the TBDATA command allows only 6 constants. In the manual it is stated that: "If constants 1-4 are input and constants 5-8 are omitted, the latter constants default as discussed", meaning C9 should be 0.6 which is the default value. However, when I edit the model in APDL C9 is set to zero. What should I do to include in the command the C9=0.6? Thank you in advance.
  
  Regards,
  
  Zoi
- October 25, 2019 at 6:29 pm
  TARTON
  Subscriber
  Heres the syntax for the TBDATA command
  
  TBDATA,Starting location in table,Maximum of 6 inputs separarted by commas
  
  If you want to enter constants 1-4 and 9 and omit 5-8, you can do so in 2 lines or 5 lines of command
  
  2 lines:
```
TBDATA,1,0.2,0.8,15,120

TBDATA,9,0.6
```
  5 lines:
```
TBDATA,1,0.2

TBDATA,2,0.8

TBDATA,3,15

TBDATA,4,120

TBDATA,9,0.6
```
- October 25, 2019 at 8:37 pm
  
  zoiralli
  Subscriber
  
  Hi TARTON,
  
  Thank you! Another question I have; how to input the tensile stress-strain experimental data for concrete? The command above is for compression and want input tension too. Is that possible?
  
  Thank you
- May 23, 2020 at 12:46 pm
  
  Semih
  Subscriber
  
  Hi,
  
  I don't think you can input tensile stress-strain data for Solid65 element. It is linear up to the tensile strength. If you want to include damage-plasticity after the tensile strength is reached, then I think you should use Microplane elements.
  
  Regards,