金属材料准静态拉伸试验中短哑铃片试样的标距修正  

On the gauge length correction for short dumbbell sheet specimen in quasi-static tensile experiment of metallic materials

作　　者：刘赛 肖凯[1] 苏玲[1] 王月[1] 吕振华[2] LIU Sai;XIAO Kai;SU Ling;WANG YueI;LV Zhen-hua(Research and Development Center,China Academy of Launch Vehicle Technology,Beijing 100076,China;Department of Automotive Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]中国运载火箭技术研究院研究发展中心,北京100076 [2]清华大学汽车工程系,北京100084

出　　处：《实验力学》2018年第5期816-822,共7页Journal of Experimental Mechanics

基　　金：国防基础科研项目JCKY2016601B001

摘　　要：为了准确获取金属材料准静态拉伸试验中短哑铃片试样的应力一应变曲线，本文以某钢材的短哑铃片试样的准静态拉伸试验为例，采用有限元仿真分析方法，分析了不同试验标距下的应力～应变曲线的差异及其原因，研究了短哑铃片试样的修正标距与材料类型和试样厚度的关系，提出了短哑铃片试样的一种标距修正方法。研究表明，短哑铃片金属试样存在应变分布不均匀现象，是由试样的边界效应引起的，而不是由颈缩失稳引起的；本文提出的标距修正方程可适用于大部分金属材料和材料厚度的短哑铃片试样，采用标距修正方程确定的试验标距，可以准确获取短哑铃片金属试样的应力一应变曲线。In order to accurately obtain the stress-strain curve of the short dumbbell sheet specimen in quasi-static tensile experiment of metallic materials, taking the quasi-static tensile experiment of short dumbbell sheet specimen of a certain steel as an example, adopting finite element simulation analysis method, the difference of stress-strain curves under different experimental gauge length condition and its causes were analyzed. Relations among the gauge length correction distance of short dumbbell sheet specimen, the type of material and the specimen thickness were studied. A method for correcting the gauge length of short dumbbell sheet specimen is proposed in this paper. Study results show that the strain distribution of short dumbbell sheet metal specimen is nonuniform, which is caused by specimen boundary effect, not by the necking instability. Gauge length modified equation proposed in this paper can be applied to most short dumbbell sheet metal specimen with different thicknesses. Stress-strain curves of short dumbbell sheet metal specimen can be accurately obtained by using the experimental gauge length determined by the calibration equation.

关 键 词：拉伸试验 金属材料 哑铃片试样 标距修正 有限元仿真 边界效应 

分 类 号：TG115.52[金属学及工艺—物理冶金]