一类新的超弹性-循环塑性本构模型

目前,很多经典的超弹性-有限塑性本构模型已被提出,但由于超弹性理论中中间构型的引入使得随动硬化法则相对复杂,故多数文献均采用的是经典的Armstrong-Frederick(A-F)随动硬化法则.本文基于已有的本构理论,利用多机制过程的概念拓展了Lion塑性变形分解理论,明确提出了多重中间构型的概念,并在此基础上,对经典理论中客观性的定义进行了概念上的推广,使其更好地适用于超弹性本构理论分析,同时提出了一类新的超弹性-有限塑性本构模型.这类本构模型满足热动力学法则,且可融合多种小变形循环塑性理论中常用的随动硬化法则(如经典的A-F模型,Chaboche模型,Ohno-Wang(O-W)模型以及Karim-Ohno(K-O)模型等),使得小变形理论中背应力的加法分解性质及其演化的临界面阶跃特性在大变形领域中均有所体现,故本文提出的本构理论可看作是小变形循环塑性模型在大变形理论中的扩展.本文最后以K-O模型为例,对推荐模型进行了详细探讨,并与相应的次弹性模型进行了对比. 

A NEW FORMULATION OF CONSTITUTIVE MODEL FOR HYPERELASTIC-CYCLIC PLASTICITY

Until now, a number of classical hyperelastic-finite plasticity constitutive models have been proposed. How-ever, most of them are based on the classical Armstrong-Frederick kinematic hardening rule in consideration of the complexity brought by the introduction of the intermediate configuration in the hyperelasticity theory. Hence, based on the existed constitutive theories, the methodology of Lion decomposition theory was extended utilizing the notion of the multi-mechanism process and clearly put forward the conception of the multi-intermediate configuration. Furthermore, the classical concept of the objectivity in the continuum mechanics for better application to the hyperelasticity theory was generalized and then a new hyperelastic-finite plastic constitutive model was proposed. The new constitutive model not only meets the thermal dynamic laws but also can incorporate several classical kinematic hardening rules which were usu-ally adopted in cyclic plasticity of infinitesimal deformation theory (e.g. the A-F model, Chaboche model, O-W model and the K-O model, etc.). Therefore, this model corresponding to finite deformation problems contains two typical char-acteristics adopted by infinitesimal deformation theory: the additive decomposition property and step mutation feature of the backstress on the critical surface. Thus, the present model can be treated as parallel to the corresponding form in the small deformation case. Finally, the situation accounting for Karim-Ohno kinematic hardening rule is under specific consideration and compared with the hypoelasticity constitutive model.