A unified viscoplasticity constitutive model based on irreversible thermodynamics  

作　　者：LIU ChangChun Lü HeXiang GUAN Ping 

机构地区：[1]State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,Dalian 116024,China [2]Prediction&Control Key Laboratory on Complicated Structure System,Dalian University,Dalian 116622,China

出　　处：《Science China(Technological Sciences)》2008年第4期378-385,共8页中国科学（技术科学英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant NO. 90410012)

摘　　要：A unified viscoplasticity constitutive model for metal materials is developed within the framework of irreversible thermodynamics, and an expression for the Helmholtz free energy function involving the parameters reflecting kinematic hardening and isotropic hardening is given. At the same time a non-associated flow potential function including the corresponding state variables is also given, from which the flow equation and the evolution equations of the internal state variables are derived. Thus, a general theoretical framework constructing a unified viscoplasticity constitutive model is given. Compared with the typical unified viscoplasticity constitutive models, the presented model evidently satisfies the irreversible thermodynamics laws. Moreover, this method not only provides a new theoretical foundation for further development of the unified viscoplasticity constitutive model, but also gives a new theoretical framework for the stress-strain analysis of more materials.A unified viscoplasticity constitutive model for metal materials is developed within the framework of irreversible thermodynamics, and an expression for the Helmholtz free energy function involving the parameters reflecting kinematic hardening and isotropic hardening is given. At the same time a non-associated flow potential function including the corresponding state variables is also given, from which the flow equation and the evolution equations of the internal state variables are derived. Thus, a general theoretical framework constructing a unified viscoplasticity constitutive model is given. Compared with the typical unified viscoplasticity constitutive models, the presented model evidently satisfies the irreversible thermodynamics laws. Moreover, this method not only provides a new theoretical foundation for further development of the unified viscoplasticity constitutive model, but also gives a new theoretical framework for the stress-strain analysis of more materials.

关 键 词：IRREVERSIBLE thermodynamics VISCOPLASTICITY UNIFIED CONSTITUTIVE kinematic HARDENING ISOTROPIC HARDENING 

分 类 号：TG111.3[金属学及工艺—物理冶金]