分析了分离式Hopkinson压杆(SHPB)系统冲击压缩试验过程中试样的应力均匀化过程.结果表明:试样内的应力分布不均匀性在冲击压缩开始时最显著,随着时间的延长,应力分布渐趋均匀;在变形初期,应力分布不均匀主要表现为试样两端的应力水平不同以及应力-时间曲线的进程不同步且伴有较大振荡;用绝对不均匀度α(t)衡量试样内应力分布的不均匀程度,在α(t)-t曲线上存在一明显的转折点M,建议用M点对应的时间表示应力均匀化所需时间.

In split Hopkinson pressure bar(SHPB) test,the stress uniformization process in specimens was studied.The results indicate that the stress non-uniformity obviously appeared at the beginning of dynamic compression,which mainly behaved as follows: the level of stress was different at the two bottoms of the specimen and the tenor of stress-time was non-synchronizing along with large vibration.In the course of time,the stress distribution in the specimen gradually got uniformed.The non-uniformity degree of stress distribution in the specimen was judged by absolute stress unevenness α(t).The curve of α(t)-t had an obvious kinkpoint M.It is suggested that the correspondent time of kinkpoint M is the time needed for stress distribution uniformization in the specimen.