A modified Johnson–Cook constitutive model for titanium alloy TA31 and its implementation into FE

Abstract The accuracy of high-temperature constitutive models is essential for the establishment and optimization of thermomechanical processing, and is one of the most relevant factors determining the reliability of finite element simulation results. In this study, attention is paid to propose a new coupled Johnson–Cook constitutive model for predicting the flow behaviors of titanium alloy TA31 composed of bimodal microstructure, and to implement it in the finite element software Abaqus. The proposed model not only takes into account the strain softening phenomenon of titanium alloy but also the coupled interactions of strain, strain rate and temperature. The correlation coefficient R and average absolute relative error AARE of the modified constitutive equation were 0.9885 and 3.6%, respectively. The mathematical formulation of the new constitutive model allows for accurate predictions of the flow stress of TA31 titanium alloy, while retaining a low identification cost of the unknown coefficients. A subroutine VUHARD of this model was developed, and its reliability was verified in the case of the modeling of one element test. It is helpful to understand the deformation behavior of titanium alloy TA31 and provide valuable references for optimizing the thermomechanical processing.