Learning Forum

[javat33489]

Hi all.

I make a test calculation of the tensile strength of the sample according to the tests performed:

 

I also created an approximation table to find the Johnson-Cook parameters:

 

 

 

But the sample does not break, it stretches endlessly. Why?

[Ram Gopisetti]

Hi javat, 

Are you sure you have calibrated the damage variables correctly from the test data?

I am not sure if you can equate the damage variables directly to the JC main model coefficient can you check if the reference you had is from a proper source? A is inherently a yield point and reaching such of level of damage is unusual and incorrect to work. 

Check the following YouTube link for the calibration of the JC correctly with strain rate cases. 

https://www.youtube.com/watch?v=F8BQNm-zYSM

https://www.youtube.com/watch?v=vRTgY1HikUQ

Cheers, Ram 

[javat33489]

Yes sir, it was from these videos that I made the Johnson Cook models.

[Bernd Hochholdinger]

Have you checked the evloution of the according damage history variable of your Johnson Cook model.

The meaning of History Variables for certain material models can be found here:

https://www.dynasupport.com/howtos/material/history-variables

History Variables can be output to d3plot via Parameter NEIPH for solid element in the Keyword *DATABASE_EXTENT_BINARY.

Cheers,

Bernd