【作者】 王小英； 马策； 石洁； 刘婷婷； 唐县娥； 张丽；

【Author】 WANG Xiao-ying~1,MA Ce~2,SHI Jie~1,LIU Ting-ting~1, TANG Xian-e~2,ZHANG Li~2 (1 Science and Technology on Surface Physics and Chemistry Laboratory,P.O.Box 718-35,Mianyang of Sichuan Prov.621907,China; 2.China Academy of Engineering Physics,P,0,Box 919-71,Mianyang of Sichuan Prov.621900,China)

【机构】 表面物理与化学重点实验室； 中国工程物理研究院；

【摘要】 为了揭示应力状态对U-5.7Nb合金中的绝热剪切带形成和发展之间的联系,对直圆柱形、阶梯形、哑铃形和圆台形等形状的U-5.7Nb合金进行了分离式Hopkinson压缩实验,利用光学显微镜分析其显微组织的变化规律,采用有限元LS-DYNA软件模拟了不同形状的U-5.7Nb合金试件在冲击载荷下的变形和剪切局部化行为。结果表明,直圆柱形试样由于变形不均匀不易产生绝热剪切带。台阶形试样容易在应力集中处产生绝热剪切带,通常伴随着裂纹的扩展。哑铃形试样由于应力集中程度较高,容易产生剪切带,因为两端的约束作用,剪切带会相对固定在应力集中区域产生。圆台形试样易在小端附近产生剪切带。有限元模拟得到的绝热剪切带位置和方向与实验结果一致,表明绝热剪切带的形成和发展与试件的应力状态密切相关。更多还原

【Abstract】 In order to reveal the influence of stress state on the form and development of adiabatic shear,the split Hopkinson press bar(SHPB) is used to impact specimen with different shape such as cylinder,step-cylinder,dumbbell and ladder-shaped specimen.The specimens after Hopkinson bar test were investigated by optical microscopy.The deformation behavior and shear localization in four specimens of uranium niobium alloys under impact loading are simulated by the finite element code LS-DYNA.The results show that the shapes of specimens effect the tendency of the adiabatic shear band(ASB) in the single axils compress state.The location and propagations of ASB predicted by present FEM simulation show good agreement with the experimental results.The calculation results show that the stress condition has significant influence on the initiation and propagation of adiabatic shear band.更多还原