# \*PLASTIC how to visualisation

**URL:** <https://calculix.discourse.group/t/plastic-how-to-visualisation/727>\
**Category:** Uncategorized\
**Created:** [September 25, 2021, 6:19am UTC](https://calculix.discourse.group/t/plastic-how-to-visualisation/727 "2021-09-25T06:19:36Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![dichtstoff](https://avatars.discourse-cdn.com/v4/letter/d/dec6dc/32.png) [@dichtstoff](https://calculix.discourse.group/u/dichtstoff)\
**Post date:** [September 25, 2021, 6:19am UTC](https://calculix.discourse.group/t/plastic-how-to-visualisation/727/1 "2021-09-25T06:19:36Z")

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I want to work with the \*PLASTIC card of CCX.  
The only experience i have is with

- elastic-plastic without strain hardening

Now i want to work with furthermore models:

- elastic-plastic with a nominal plateau slope
- elastic-plastic with linear strain hardening
- true stress-strain curve

how can i make my input easiest visualised for checking my input?  
can i use a spreadsheet? or is there still a solution?  
(I’m not sure working with the values of the \*PLASTIC card and how to control easy  
without tensile test calc.!?!)

or can give me someone examples of these different material behaviour?

i’m grateful for each tip and support

 ![image](https://global.discourse-cdn.com/free1/uploads/calculix/original/1X/58d9b97c74955494bbac721dd81fbb124eb1d99e.png)

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**Author:** ![Calc\_em](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\
**Post date:** [September 25, 2021, 7:41am UTC](https://calculix.discourse.group/t/plastic-how-to-visualisation/727/2 "2021-09-25T07:41:16Z")

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In CalculiX it all comes down to specifying subsequent points from the plastic part of the stress-strain curve. The usual approach in this and other programs is to use spreadsheet (Excel or its equivalents like LibreOffice Calc) where we define the data pairs, plot curves from them and copy the values to the input file for analysis. The spreadsheet becomes especially useful when we obtain the stress-strain data from experiment.

When you test new material models, it’s good to run single element tests first - you can analyze one hexahedral element subjected to uniaxial load.

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<div class="post-metadata">

**Author:** ![dichtstoff](https://avatars.discourse-cdn.com/v4/letter/d/dec6dc/32.png) [@dichtstoff](https://calculix.discourse.group/u/dichtstoff)\
**Post date:** [September 25, 2021, 11:31pm UTC](https://calculix.discourse.group/t/plastic-how-to-visualisation/727/3 "2021-09-25T23:31:46Z")

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is one more data pairs enough for creating bilinear material behaviour?  
with E=210000 and yield plateau 235

material behaviour a:

\*PLASTIC  
235,0

material behaviour b:

\*PLASTIC  
235,0  
236,(1/(210000/10000))

material behaviour c:

\*PLASTIC  
235,0  
236,(1/(210000/100))

wbr

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<div class="post-metadata">

**Author:** ![Calc\_em](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\
**Post date:** [September 26, 2021, 8:00am UTC](https://calculix.discourse.group/t/plastic-how-to-visualisation/727/4 "2021-09-26T08:00:01Z")

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Yes, we define the bilinear model by providing two data points and it’s usually done this way:

yield\_stress, 0 plastic strain  
ultimate\_tensile\_strength, strain at break