宏微观耦合本构模型参数识别取值范围研究

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

宏微观耦合本构模型的参数识别往往通过反分析方法进行,为了使参数识别结果具有高的置信度,需要确定合适的参数取值范围.基于动态再结晶过程的微观机理以及相应本构方程的数学特征,提出一个确定参数取值范围的方法.首先详细给出考虑动态再结晶的黏塑性本构模型,并根据模型构造物理机理,提出通过6步确定该模型参数取值范围的方法;其次,对300 M低合金钢进行不同温度、应变速率下的热变形试验,测试宏观的流动应力-应变数据及微观的组织数据;然后应用提出的方法,依据试验数据,确定参数取值范围;最后,基于确定参数取值范围中获得的知识,对模型进行局部修改,使模型模拟结果更接近实验结果.

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 300 M 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.