大尺寸Hopkinson压杆及其应用

本文介绍了国内最大尺寸的SHPB装置;讨论了在大尺寸SHPB装置上测量混凝土类材料动态力学性能将会出现的几个问题;采取了在入射杆的打击端加设波形整形器,在试件与杆件之间加设万向头及在试件上直接测量应变等新的实验技术及采用新的数据处理方法,提高了试验结果的精确度和可信度;简要介绍了利用ф100 SHPB装置对四种体积含量(0,2%,4%和6%)钢纤维高强混凝土进行三种应变率(10~20/s,35~45/s和75~85/s)的冲击压缩实验。实验结果表明,钢纤维高强混凝土具有较强的应变率效应,其破坏应力、峰值应变随应变率增加而显著增加,弹性模量也随应变率增加而增加。另外,钢纤维含量对混凝土具有增韧效应,随着钢纤维含量的增加,其韧性增大,脆性降低。

Large Dimension Hopkinson Pressure Bar and Its Application

In this paper,the most largest dimension split Hopkinson pressure bar(SHPB) at home is introduced.Some problems of large dimension SHPB technique used for measuring dynamic behaviors of concrete and concrete-like materials are discussed.The precision and reliability of testing results are heightened because several novel testing techniques are adopted,including: 1) a pulse shaper is settled at the free end of input bar;2) a gimbal is settled between specimen and bar;3) the stain of specimen is directly measured by strain gauge;and 4) a new date processing method is introduced.Impact compressive expressive experiments of high strength steel fiber reinforced concretes with four contents(0,2%,4% and 6%)under three strain rates(10~20/s,35~45/s and 75~85/s)are briefly introduced.The experimental results show that the high strength steel fiber reinforced concretes is more sensitive to strain rate.The destroy stress,peak strain and elastic modulus obviously increase with strain rate increasing.The content of steel fiber have toughening effect on the concrete materials,that is the toughness of concrete increases and its brittleness decreases with an increase of content of steel fiber.