The deformation behavior of the dual phase steel （DP1000 steel） was studied by the quasi-static tensile ex-periment and the dynamic tensile experiment. The experiments were carried out at strain rates ranging from 1...The deformation behavior of the dual phase steel （DP1000 steel） was studied by the quasi-static tensile ex-periment 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^-4-2000 s^-1 were measured. By introducing the strain rate sensitivity factor m, Zerilli Armstrong model was optimized. The con- stitutive equation parameters which formulate the mechanical behavior of DP1000 steel were fitted based on the John-son-Cook （JC） constitutive model and the optimized Zerilli-Armstrong （ZA） constitutive model, respectively. By comparing indicators of ＂accuracy-of-fit＂, Rz terms, for the two models, the optimized Zerilli-Armstrong constitu-tive 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.展开更多
Strain hardening,strain rate strengthening and thermal softening data of C5191 phosphor bronze at highspeed blanking are not easy to be obtained with a general measure method,therefore,it is quite difficult to establi...Strain hardening,strain rate strengthening and thermal softening data of C5191 phosphor bronze at highspeed blanking are not easy to be obtained with a general measure method,therefore,it is quite difficult to establish the dynamic constitutive model.To solve this problem,the tensile properties at a strain rate of 1 s^(-1) by GLEEBLE-3500,and dynamic tensile conditions at strain rates of 500,1 000 and 1 500 s^(-1) by split Hopkinson tensile bar (SHTB) apparatus are studied.According to these test data,the classic Johnson-Cook equation is modified.Furthermore,the modified Johnson-Cook equation is validated in the physical simulation model of high-speed blanking.The results show that the strength of C5191 phosphor bronze maintains a certain degree of increase as the strain rate increasing and presents a clear sensitivity to strain rate.The modified Johnson-Cook equation,which has better description accuracy than the classical Johnson-Cook equation,can provide important material parameters for physical simulation models of its high-speed blanking process.展开更多
基金Item Sponsored by National High Technology Research and Development Program(863Program)of China(2009AA03Z518)Basic Theory Research Fund of Engineering Research Institute of USTB of China(YJ2010-006)
文摘The deformation behavior of the dual phase steel （DP1000 steel） was studied by the quasi-static tensile ex-periment 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^-4-2000 s^-1 were measured. By introducing the strain rate sensitivity factor m, Zerilli Armstrong model was optimized. The con- stitutive equation parameters which formulate the mechanical behavior of DP1000 steel were fitted based on the John-son-Cook （JC） constitutive model and the optimized Zerilli-Armstrong （ZA） constitutive model, respectively. By comparing indicators of ＂accuracy-of-fit＂, Rz terms, for the two models, the optimized Zerilli-Armstrong constitu-tive 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.
基金supported by Zhejiang Provincial Natural Science Foundation of China(No.LY18E050005)
文摘Strain hardening,strain rate strengthening and thermal softening data of C5191 phosphor bronze at highspeed blanking are not easy to be obtained with a general measure method,therefore,it is quite difficult to establish the dynamic constitutive model.To solve this problem,the tensile properties at a strain rate of 1 s^(-1) by GLEEBLE-3500,and dynamic tensile conditions at strain rates of 500,1 000 and 1 500 s^(-1) by split Hopkinson tensile bar (SHTB) apparatus are studied.According to these test data,the classic Johnson-Cook equation is modified.Furthermore,the modified Johnson-Cook equation is validated in the physical simulation model of high-speed blanking.The results show that the strength of C5191 phosphor bronze maintains a certain degree of increase as the strain rate increasing and presents a clear sensitivity to strain rate.The modified Johnson-Cook equation,which has better description accuracy than the classical Johnson-Cook equation,can provide important material parameters for physical simulation models of its high-speed blanking process.
