Nonlinear behavior of steel materials
I have problem with 2 steel materials and finding theirs correlation with real tensile strength tests.
I've tested 3 materials (on tensile strength machine, according to: ISO 6892) and then I put material data into ANSYS and wanted to receive similar results.
To check when the sample "breaks" in ANSYS I use this Eurocode 3 equation "50*(Re/Young Modulus)" and compare it with plastic strain in ANSYS.
For material 1.4310 results are very good, real sample broke at 19.5kN and I got plastic strain about 0.2 at 19.9kN - that's correlation above 97% (but weird thing is that simulation crashes few substeps after this threshold - I think it shouldn't but maybe it's some clue to further investigation).
But for materials 1.4301 and 1.4509 I got worse results.
1.4301 in real test broke at 13.6kN and in ANSYS it "breaks" at 10,5kN - correlation: 76%.
1.4509 in real test broke at 9,5kN and in ANSYS it "breaks" at 8,1kN - correlation: 85%.
I created special excel file, to convert elongation and force (output data) into true stress and plastic strain for all 3 steels, sample:
Then for future analysis I took only True stresses above Re and only to maximum value (no decreasing) and I got this curve (sorry for no values but I can't give you them)
My testing setup:
I'm using two surfaces, one fixed and one allowed movement in Y axis - where I apllied force - all just to simulate grips in tensile machine.
On the other side I have displacement - where I also check applied force.
Does anyone had this kind of problem before?