摘要
脉冲整形常被用来修正霍普金森压杆的入射波形,以保证加载过程中试件的应力均匀性和恒应变率.本文提出了一种具有较好的波形整形效果和较宽适用范围的分离式霍普金森压杆(SHPB)入射波整形方法.采用真空封泥这种可忽略强度的材料作为入射波的波形整形器,结合撞击速度调整封泥的用量,可以得到正弦函数及缓升平台的类梯形波等不同的整形效果.数值模拟分析表明,真空封泥的波形整形效应主要由材料变形过程中的径向惯性效应控制.应用实例显示,经波形整形的SHPB实验试件两端的应力平衡得到较大的改善.
In the split Hopkinson pressure bar （SHPB） experiment, the state of dynamic stress equilibrium should be achieved over most of the test duration. Therefore, pulse shaping techniques which can modify the profile of the incident pulse are usually needed. In this paper, a new method for SHPB incident pulse shaping is presented. The vacuum cement material of which the strength can be ignored is used as the pulse shaper. The experimental results show that, with this method, satisfactory shaping effect can be obtained in a wide application scope. Combining the adjustment of the impact velocity and the amount of the vacuum cement, different shaping results such as sinusoid, slow-rise trapezoid can be obtained. This result would meet the needs of the dynamic stress equilibrium or constant strain rate loading in SHPB experiments. The numerical simulation result indicates that the shaping function of the material is mainly due to the radial inertial effect in the high velocity deformation process of vacuum cement.
出处
《中国科学：技术科学》
EI
CSCD
北大核心
2016年第4期393-399,共7页
Scientia Sinica(Technologica)
基金
国家自然科学基金(批准号:11390361
11572299)资助项目
