whenisimulate my CT specimen in Abaquse with Elastic-Plastic propertic my plastic zone in crack tip is lower than experimentall. i obtaine true stress and true strain from tensile test with this equation=
trueestress=log(1+stress);
plasticstrain=truestress-sigma/E;
do you know what can i do for my materiall that show ductile behavior?
after looking at your model and the mesh and crack tip mesh destritisation only , i can comment on this problem. The formulae that you are using is only valid upto uniform elongation stage, did you use it upto fracture, what model u r using in your analysis, 2D or 3D, what is the thickness of ur CT specimen.
2D with thinckness of 10mm
i obtained stress strain data from uniform elonation of tensile test.
If it is 2D , what assumption u have taken PS or PN?, i hope u might have taken PN, and if you compare it with exp results than it is suppose to be greater as pure Pn condition is only prevailing near the thickness and that too upto certain thickness of specimen, This plane straining prevailing thickness is material dependent. I THINK THE MAIN PROBLEM IN YOUR WORK MAY BE THAT YOU ARE ASSUMING PLANE STRAIN CONTION IN YOUR FEM MODEL AND YOU ARE COMPARING WITH EXPERIMENTAL MEASURED SIZE OF PLASTIC ZONE MEASURED ON THE FRACTURE SPECIMEN SURFACE WHERE THE CONDITION IS MORE OF PLANE STRESS AND HENCE THE SIZE IS GREATER IN EXPERIMENTAL RESULTS AS COMPARED TO FEM RESULTS UNDER PLANE STRAIN 2D ASSUMPTION, good LUCK
thank you
yes i accept your argument . i simulate it plane strain. i think really my plastic one is low but crack tip change color to white a bit
Hi dear Asgar,
the stress state (Plane stress or Plane strain) is really effective in the plastic zone size!
Good luck
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