# Syntaxis for Johnson cooke model

**URL:** <https://calculix.discourse.group/t/syntaxis-for-johnson-cooke-model/2485>\
**Category:** Uncategorized\
**Created:** [November 21, 2024, 3:34pm UTC](https://calculix.discourse.group/t/syntaxis-for-johnson-cooke-model/2485 "2024-11-21T15:34:32Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Juseche](https://avatars.discourse-cdn.com/v4/letter/j/258eb7/32.png) [@Juseche](https://calculix.discourse.group/u/Juseche)\
**Post date:** [November 21, 2024, 3:34pm UTC](https://calculix.discourse.group/t/syntaxis-for-johnson-cooke-model/2485/1 "2024-11-21T15:34:32Z")

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Hi!,  
I’m trying to use CCX 2.21 with Johnson Cooke plasticity model. This is the block of material that I’m using in the input file:

\*MATERIAL, name=mat  
\*DAMPING,ALPHA=2.5,BETA=0.0  
\*DENSITY  
0.2840  
\*ELASTIC  
2.940000e+07,0.260000,0  
\*PLASTIC, HARDENING=JOHNSON COOK  
83875, 20648, 0.3064, 1, 0.0, 0.0  
\*RATE DEPENDENT, TYPE=JOHNSON COOK  
0.045, 0.015

However, at running, these errors appears:

\*ERROR reading \*PLASTIC  
the name of a Johnson Cook material  
must start with JOHNSONCOOK  
(blanks are allowed at any location  
and the string is not case sensitive)  
\*ERROR reading \*RATE DEPENDENT. Card image:  
\*PLASTIC,HARDENING=JOHNSONCOOK

\*ERROR reading \*RATE DEPENDENT  
the name of a Johnson Cook material  
must start with JOHNSONCOOK  
(blanks are allowed at any location  
and the string is not case sensitive)  
\*ERROR reading \*RATE DEPENDENT. Card image:  
\*RATEDEPENDENT,TYPE=JOHNSONCOOK

Then, what is the correct syntaxis for the Johnson cooke model?.

Thanks in advance,

Jack.

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<div class="post-metadata">

**Author:** ![Disla](https://yyz2.discourse-cdn.com/free1/user_avatar/calculix.discourse.group/disla/32/3548_2.png) [@Disla](https://calculix.discourse.group/u/Disla)\
**Post date:** [November 21, 2024, 7:08pm UTC](https://calculix.discourse.group/t/syntaxis-for-johnson-cooke-model/2485/2 "2024-11-21T19:08:08Z")

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> [@Juseche](#):
>
> \*ERROR reading \*PLASTIC  
> the name of a Johnson Cook material  
> **must start with JOHNSONCOOK**

Means

\*MATERIAL, name=mat

should be for example :

\*MATERIAL, name=JohnsonCook\_mat

I would say the second error is probably a consecuence of the first.

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<div class="post-metadata">

**Author:** ![Juseche](https://avatars.discourse-cdn.com/v4/letter/j/258eb7/32.png) [@Juseche](https://calculix.discourse.group/u/Juseche)\
**Post date:** [November 25, 2024, 4:58pm UTC](https://calculix.discourse.group/t/syntaxis-for-johnson-cooke-model/2485/3 "2024-11-25T16:58:47Z")

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Thanks!. Now it working. Cheers.