STUDY ON THE PARAMETER VALUE DOMAIN OF MACRO-MICRO CONSTITUTIVE MODEL

Parameter identification of macro-micro coupled constitutive model is generally taken through inverse analysis. To make the identified result with high confidence level, the reasonable parameter value domain must be given. Based on the physical mechanism during dynamic recrystallization and the mathematical characteristics of the constitutive equations, a procedure to determine the value domain of the parameters is proposed, which are involved in a macro-micro coupled constitutive model considering dynamic recrystallization. Firstly, the detail of the viscoplastic constitutive model is given, and a six-step method for the determination of the parameter value domain is given based on the physical mechanism; secondly, the hot compression deformation of low alloy steel 300M is carried out under different combinations of temperatures and strain rates, the datum on true stress-strain curves and microstructures are obtained. Based on the proposed procedure and the corresponding experimental datum, the parameter value domain is given. At last, the model is locally improved based on the information obtained during the above procedure.