梯度纳米结构IF钢的协同强化本构模型  

Constitutive model characterizing synergistic hardening effect of gradient nanostructured IF steel

作　　者：王效贵[1] 胡家诚 赵伟奇 许杨剑[1] WANG Xiaogui;HU Jiacheng;ZHAO Weiqi;XU Yangjian(College of Mechanical Engineering,Zhejiang University of Technology,Hangzhou 310014,China)

机构地区：[1]浙江工业大学机械工程学院,浙江杭州310014

出　　处：《浙江工业大学学报》2019年第2期151-157,共7页Journal of Zhejiang University of Technology

基　　金：国家自然科学基金资助项目(51175469)

摘　　要：提出了一种基于显微硬度建立梯度纳米结构IF钢的本构模型的新方法,并通过单轴拉伸过程的有限元模拟研究了应力状态演化。首先将梯度纳米结构层划分为12个等厚度薄层,假设各薄层与芯部粗晶的力学性能可用Hollomon硬化准则和GTN损伤模型表征,通过基于实验的反演算法识别出模型中的材料参数,从而建立了表征梯度纳米结构IF钢的协同强化效应和损伤演化的本构模型。通过模拟梯度纳米结构IF钢的单向拉伸过程,获得了材料在拉伸过程中依次经历的3种应力状态,即纯弹性变形时的单轴拉伸应力状态、表层受压芯部受拉的多轴应力状态和表层受拉芯部受压的多轴应力状态。基于有限元模拟得到的轴向应力—轴向应变曲线,准确预测了不同梯度层占比时的临界失稳应变。The constitutive model of gradient nanostructured IF steel based on microhardness is developed in this work. The gradient nanostructure layer is divided into 12 pieces of thin layer. The mechanical properties of each thin layer and the coarse grain core are assumed to be characterized by the Hollomon hardening criterion and the GTN damage model. The material parameters of the constitutive model are identified by the inverse analysis based on the experimental data. The developed constitutive model is able to characterize the synergistic strengthening effect and damage evolution of gradient nanostructured IF steel. The constitutive model is used to analyze the evolution of multi-axial stress state under uniaxial tension. The finite element results indicate three successive stress states: the uniaxial tensile stress state, the multi-axial stress state with compressive surface and tensile core, and the multi-axial stress state with tensile surface and compressive core. In addition, the critical instability strains of the gradient nanostructured IF steel plates with different thickness ratios of gradient nanostructured layer are predicted based on the axial stress-axial strain curve obtained by finite element simulation.

关 键 词：梯度纳米结构IF钢 协同强化效应 本构模型 显微硬度 多轴应力状态 

分 类 号：O34[理学—固体力学]