LAW2 parameter for residual plasticity on stress reduction [NOT SOLVED]
Altair EmployeeWhen the stress is less than the yield stress, if the stress is removed, the material follows the same path on stress-strain curve and regains from the deformation.
But if stress goes beyond elastic limit, there is permanent deformation even after removal of stress.
I want to define this property for the Johnson Cook law 2.
I am observing that after deformation, there is no strain reduction even though stress reduces. It may be elastic or plastic but there should be some! There is none currently.
Answers
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Hi,
If it is in elastic region, the strain should reduce but when it is in plastic region, it may not.
How are you defining the curve?
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It is law2 - Johnson Cook, so I have defined the a,b and n constants.
Even when the material deforms plastically, upon unloading there should be reduction in strain according to Young's modulus. See the image below:
https://www.princeton.edu/~maelabs/mae324/glos324/plasticdeformation.htm
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Hi Bongirs,
I agree, after unloading there should be some reduction in strain to allow elasticity.
Can you try with a Stress strain curve using LAW 36?
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Is there a difference in behaviour between law 2 and law 36 even if we provide similar stress strain curve?
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I think you can have more control over loading and unloading in LAW 36.
How are applying unloading parameters in LAW2?
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I think you can have more control over loading and unloading in LAW 36.
How are applying unloading parameters in LAW2?
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I didn't know there are unloading parameters..
The unloading has to be parallel to elastic line, right? All materials behave this way so why are there parameters?
I was expecting to see this unloading done automatically but as you said I have to put some parameters for this. Please tell me what to fill for law2?
How law 36 has more control?
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Altair Forum User said:
I didn't know there are unloading parameters..
The unloading has to be parallel to elastic line, right? All materials behave this way so why are there parameters?
I was expecting to see this unloading done automatically but as you said I have to put some parameters for this. Please tell me what to fill for law2?
How law 36 has more control?
I mean to say you can input 2 functions. one for loading and the other for unloading for different strains.
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hmm... I am confused now.
How can we select whether a defined curve is for loading or unloading?
We can have two different curves for different strain rates, but they always go from left to right on the graph i.e. loading always.
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