LAW36 material curve assignment? [SOLVED]
Altair EmployeeHello,
In the RD-xxxx tutorials the stress-strain curve is assigned to fct_ID1, but I cannot find it in my Hypermesh. There is a curve assignment field under fct_ID_E, and one more field under the NFunc. If I assign it for fct_ID_E, RADIOSS gives an error that stress should decrease as plastic strain increases. If I assign to the field under NFunc, it also needs scale and EPS_DOT.
1. What are these two parameters?.
2. Eventually, where do I provide the curve?
3. Also, after creating the material, is there a way to view the true stress - strain curve just to confirm that RADIOSS interprets it correctly? I also tried the Johnson Cook material model but the results were way wrong (strain of >200% when the fail strain is 8%). So I just want to make sure the fields I am entering have correct interpretation by checking with the total stress strain curve.
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Altair Employee 
What you see is different from what I see. Anyway that is a bug.
Altair EmployeeHello Bongris,
So, I was using an older version of HW here. Sorry for the confusion.
Click the N_func and input 1. This will open a tab right below to refer the curve.
Altair EmployeeYeah that works for me! Thanks! Can you tell me what is the meaning of scale and EPS_DOT (is this strain rate for the stress-strain curve?)? The stress-strain curve is all that matters, so does RADIOSS calculate different stresses than the curve using the strain rate at that stage and then extrapolating using some theory?
Altair EmployeePrakash can you please tell me what is scale and EPS_DOT for the curve function?
Hi,
This refers to the strain rate which is usually obtained form the testing data. Consider a tensile test of specimen, the rate at which it is displaced during the test is referred to as the EPS_DOT. In hypermesh, we can provide different values of the same along with the corresponding curves. Please find the attached image and for more details go the help content of MAT 36.
<?xml version="1.0" encoding="UTF-8"?>
Altair EmployeeThanks for your reply Gopal!
I wanted ask how RADIOSS uses the strain rate value?
For example, if the curve is with a rate 0.1 per second, how does this value get used in any way?
If the simulation has strain rate of 1 per second, will RADIOSS use a different stress-strain curve than the input?
The user guide is not at all detailed, it only gives one liner definitions.
Altair EmployeeCan someone please answer my question?
Altair EmployeeCan you check the law characterization document in help menu where Elasto-plastic material law characterization in RADIOSS is explained.
HI,
Maybe you should scroll down a lil bit when you edit the material card.
<?xml version="1.0" encoding="UTF-8"?>