韧性材料颈缩主应力面上应变分布假定的研究  

On the Assumption of Strain Distribution on the Necking Principal Stress Surface of Ductile Materials

作　　者：董事尔[1] 李婷[1] 鲜岸江 DONG Shier;LI Ting;XIAN Anjiang(Key Laboratory of Structural Engineering in Sichuan Universities,Southwest Petroleum University,Chengdu 610500,Sichuan,China;Sichuan Provincial Architectural Design and Research Institute,Chengdu 610000,Sichuan,China)

机构地区：[1]西南石油大学四川省高校结构工程重点实验室,四川成都610500 [2]四川省建筑设计研究院,四川成都610000

出　　处：《力学季刊》2020年第2期249-257,共9页Chinese Quarterly of Mechanics

基　　金：国家自然科学基金(51574198)。

摘　　要：为了深入研究韧性材料主应力面的应变分布情况,讨论Bridgman关于主应力面上应变均布假定的精度.本文首先结合断口学基本理论与在室温条件下拉伸断裂的Q235钢、40Cr钢和45#钢断口电子显微镜扫描结果,从微观角度分析其韧窝分布后发现应变均布假定存在一定的误差;然后基于体积守恒和Aramis三维应变观测系统测得的试验结果,将计算值和试验值进行对比分析发现,三种材料中除含碳量较高的45#钢外,应变均布假定并不适用于分析颈缩主应力面上应变分布.本文的研究成果可为进一步研究韧性材料颈缩大塑性阶段的应力、应变本构关系提供一定的参考.To study the strain distribution on the principal stress plane of ductile materials,the accuracy of Bridgman’s assumption of uniform strain distribution on the necking principal stress plane is discussed.In this paper,based on the basic theory of fractography and the scanning results of electron microscope on the fracture surfaces of Q235 steel,40 Cr steel and 45#steel at room temperature,the distribution of dimples is analyzed from the microcosmic point of view.It is found that there are some errors from the assumption of uniform strain distribution.Then,based on the experimental results of volume conservation and Aramis three-dimensional strain observation system,and comparing the calculated results with the experimental results,it is found that the assumption of uniform strain distribution is not suitable for the analysis of strain distribution on the principle stress plane of necking except for 45#steel with high carbon content.The results in this study can provide some references for the further study of the stress-strain constitutive law of ductile materials in the large plastic stage of necking.

关 键 词：颈缩 断口学分析 应变分布 韧性断裂 

分 类 号：TB31[一般工业技术—材料科学与工程]