基于Aramis系统的韧性材料颈缩段应变分析  

Strain analysis on necking segment of ductile materials based on Aramis system

作　　者：董事尔[1] 鲜岸江 杨宝臻 王毅恒 林吉莉 赵梦柯 DONG Shi-er;XIAN An-jiang;YANG Bao-zhen;WANG Yi-heng;LING Ji-li;ZHAO Meng-ke(Sichuan Key Laboratory of Structural Engineering,Southwest Petroleum University,Chengdu 610500,China;Sichuan University of Science&Engineering,Zigong 643000,China;Sichuan Univers让y of Science&Engineering,Zigong 643000,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,成都610500 [2]西华师范大学,南充637000 [3]四川轻化工大学,自贡643000

出　　处：《实验力学》2020年第1期100-108,共9页Journal of Experimental Mechanics

基　　金：国家自然科学基金项目(51574198);四川省教育厅项目(16ZB0246);桥梁无损检测与工程计算四川省高校重点实验室项目(2017QYY01)

摘　　要：为了研究韧性材料在颈缩状态下颈部的应力分布,本文首先从理论入手,对比了传统的颈缩半经验应力解--Bridgman解和陈篪解。详细讨论了两解的差异,指出陈篪解的精度高于Bridgman解。然后,在室温下对16组Q235和Q345钢材进行了单轴拉伸实验,并在此过程中利用Aramis系统同步进行跟踪测量,得到了材料在颈缩段最小截面上的半径和表面轴向应变。最后,利用这些实验数据对比讨论了两解的精度和造成误差的原因。结果表明:造成陈篪解误差的原因是在整个颈缩过程中,应变均布假定并不能得到很好的满足,且在整个颈缩过程中,颈部最小截面上的径向应变的值始终大于环向应变。本文研究得到的成果,能为今后研究者计算颈缩段应力分布提供依据,并为分析韧性断裂机理提供参考。In order to study the necking stress distribution of ductile materials, the traditional necking semi-empirical stress solutions including the Bridgman formula and the Chenchi formula, were first compared theoretically. The differences between two formulas were discussed in detail, and it was pointed out that the accuracy of the Chenchi formula is higher than that of the Bridgman formula. Then, the uniaxial tensile tests in 16 groups of Q235 and Q345 steels were carried out at room temperature. In this process, the Aramis system was used for measuring deformation synchronously, and deformation parameters and surface axial strain in necking segment were obtained. Finally, the accuracy of the two formulas and the reasons for errors were discussed based on the experimental data. The results show that the error in the Chenchi formula comes from the strain distribution assumption that cannot be satisfied in the whole necking process. Meanwhile, the radial strain on minimum necking plane is always greater than the circumferential strain in the whole necking process. The present results can provide a basis for future investigation on calculating the stress distribution in necking segments, and provide a reference for analyzing the mechanism of ductile fracture.

关 键 词：颈缩 应力解 应变分布 Aramis系统 

分 类 号：TB31[一般工业技术—材料科学与工程]