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ABAQUS Johnson-Cook damage model
The constants of the Johnson–Cook fracture criterion D1, D2 ，D3，D4 and D5 are identified from tensile tests or torsion tests, but I don't kown about the specific procedure to obtain the constants. sigma*=sigma(m)/sigma,sigma(m) is the average of the three normal stresses,sigma is the von Mises equivalent stress. The sigma （stress）obtained from the tests is corresponding to the which sigma in the equation. Thanks for your information 。
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It's very common to
It's very common to calibrate material model parameters using optimization. You build a simulation of your test and compare the resulting curves of interest (stress-strain, force-deflection, whatever makes sense for the material model and testing performed). You then minimize the difference between the curve from testing and the curve from simulation, with the material model constants as design variables. See the brief below for an example.
http://www.redcedartech.com/pdfs/Abaqus_Matl_Calibration_TB_07_HEEDS_1.pdf
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