The Parameters should be known or can be determined from a tensile test by fitting the results with, for example, the Hollomons curve.

Franco

Thank you Franco for your kind reply.

Is there any relevant example to do so from tensile test?

According to the well known Lemaitre & Chaboche book, the C and gamma parameters have to be estimated on stabilised stress-strain cycles. This is particularly important if you want to simulate cyclic behaviour 

Thank you Prof. Benasciutti,

Can't we have some arbitrary values for particular grade of steel ?

Moreover, if we are determining those parameters from cyclic curves, then how do we simulate the steel material to get the aforementioned cyclic curves ? 

Thank You,

If you are very lucky, you can find material parameters in the literature. Otherwise, you need to estimate them from experimental cyclic tests.

For simulating stress-strain cycles with hardening/softening, you need a combined isotropic+kinematic non-linear models. Anyway, I suggest to refer to basic theory, e.g. book by Lemaitre & Chaboche

Please check this article:

1986 Time-independent constitutive theories for cyclic plasticity-chaboche

hi

I am working on the mechanical behavior of Ti-6al-4v on a microstructure level with crystalline plastic theory. But I have trouble to get the hard parameters. for calibrating the hardness parameters with the experimental model, there is not any experimental result on the micro level . How can I get the hardness parameters of this material?

best regrads