Could you let me know the unit of axis of plastic strain ?
Is Max value “1” that we can input ?
Strain is unitless but it’s often expressed in % (not in the software though). It can be higher than 1 (100%).
Dear FEAnalyst san
Thank you for your kindly reply!!
I would like to test material that has 0.2% endurance
Is Material Data Points(Table) ok ??
Yield stress Plastic strain
200 0.002
5000 1
The first point needs to have zero plastic strain. Then you can specify the remaining points from the stress-strain curve as you did here.
did you mean, it will fail at 0.2% elongation?
CalculiX plastic material can not enter these rupture areas, only in plastic region not to further in fractures. the stiffness of element nodes is small or nearly zero at above the yield point. then it will redistribute the stress and strain around.
0.2% strain limit is not ductile ones, common metal materials have 20% elongation. however about 5% in some areas may indicate the part is starting to fails.
so, it may plasticity definition material above is not appropriates to your models. another nonlinear material type is required.
Did you mean plastic strain zero at yield…
Dear synt san,
I am so sorry. My English is very poor.
I would like set 0.2% offset line on Prepomax like below URL
(161) How to draw 0.2% Offset Line on a Stress-Strain graph - YouTube
Thank you for your reply.
me too 
sometimes or frequently maybe
PrePoMax tabulated input value for plastic definition use true strain-strain not engineering.
in case engineering stress-strain provided by labs directly without conversion to tabulated true stress-strain curve. you may refer to Ramberg-Osgood material input parameter using keyword editor.
btw, are the material is stainless steel? in case structural steel (e.g ship, bridge/building) there’s an approach curve recommend by code regulation.
The material is stainless steel…
May I ask if this curve is the same to ABAQUS?
The “Yield Stress” is actually “True Yield Stress”, which requires the following transfers.
Yes, CalculiX also uses true stress. From the CalculiX User’s Manual:
All CalculiX input (e.g. distributed loading) and output is in terms of true stress.
Hello. I am following this topic.
could you provide an example of a elastic-plastic input, for a simple steel or aluminum?
Thanks.
For steel, plasticity definition can look like this, for instance (stress in MPa):
235 —— 0
410 —— 0.2
i made curve approximation (grey line) for common structural steel based on several tests from references. It can be categories as mild, medium and high strength steel.
an approximation of coefficient depending on yield strength is defined to fit the actual curve from steel coupon test.
above curve data points in the bracket can be used as initial input values for preliminary analysis when the actual test is not yet ready or available.
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THANK YOU.
very much appreciated.