The deformation behavior of the dual phase steel (DP1000 steel) was studied by the quasi-static tensile experiment and the dynamic tensile experiment.The experiments were carried out at strain rates ranging from 10-4 to 2 000 s-1 at room temperature.Then the stress-strain curves of DP1000 steel in the strain rate range of 10-4-2 000 s-1 were measured.By introducing the strain rate sensitivity factor m,Zerilli-Armstrong model was optimized.The constitutive equation parameters which formulate the mechanical behavior of DP1000 steel were fitted based on the Johnson-Cook (JC) constitutive model and the optimized Zerilli-Armstrong (ZA) constitutive model,respectively.By comparing indicators of "accuracy-of-fit",R2 terms,for the two models,the optimized Zerilli-Armstrong constitutive model can reflect plastic deformation behavior both at the low and high strain rates more accurately.The reasons why the optimized Zerilli-Armstrong constitutive model is more advantageous than the Johnson-Cook model were discussed by using the yield strength and ultimate tensile strength (UTS) versus strain rates,and strain hardening rate versus effective plastic strain analytical methods.
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