面心立方金属的基于位错密度的循环本构模型  

Cyclic Constitutive Model Based on Dislocation Density of Face-centered Cubic Metals

作　　者：任学红 杨绍普[2] 文桂林[1] 赵文杰 REN Xuehong;YANG Shaopu;WEN Guilin;ZHAO Wenjie(State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,Hunan University,Changsha 410082,China;State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University,Shijiazhuang 050043,China)

机构地区：[1]湖南大学汽车车身先进设计制造国家重点实验室,湖南长沙410082 [2]石家庄铁道大学省部共建交通工程结构力学行为与系统安全国家重点实验室,河北石家庄050043

出　　处：《湖南大学学报（自然科学版）》2020年第4期76-81,共6页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金联合基金资助项目(U1534204);国家自然科学基金重大资助项目(11790282)。

摘　　要：在晶体塑性理论框架下,建立适用于面心立方金属多晶材料的基于位错密度的循环本构模型.在各向同性硬化律中总位错密度被离散为螺位错和刃位错两部分,考虑了位错增殖、湮灭和相互作用的演化机制,同时采用了修正的非线性随动硬化律,建立单晶的循环本构模型,通过显式尺度过渡准则,把该模型拓展到多晶尺度.应用该模型模拟了典型面心立方结构材料多晶铜的棘轮行为.数值模拟结果表明,该模型不仅可以从多晶尺度模拟材料的棘轮行为和循环硬化特征,还可以从单晶尺度预测不同晶向和不同应力水平下的棘轮行为.Under the framework of crystal plasticity theory,a cyclic constitutive model based on dislocation density for face-centered cubic metals is proposed.The total dislocations are discretized into edge and screw components,and the multiplication,annihilation and interaction of dislocations are considered as the basic evolutionary mechanisms.At the same time,a cyclic constitutive model of single crystal is established by using the modified non-linear kinematic hardening rule.Then,the model is extended from single crystal scale to polycrystalline scale by explicit scale transition rule.The ratchetting strain of polycrystalline copper with typical face-centered cubic structure is simulated by using the proposed model.The numerical results show that the model can not only simulate the ratchetting strain and cyclic hardening characteristics of materials at polycrystalline scale,but also predict the ratchetting of materials at different orientations and stress levels from single crystal scale.

关 键 词：位错密度 晶体塑性 本构模型 棘轮行为 

分 类 号：O345[理学—固体力学]