混凝土动态力学量的应变计直接测量法

Strain Gauge Measurement Method of Dynamic Behavior for Concrete

本文介绍了用应变计直接测量混凝土动态应力-应变曲线的试验研究。讨论了分离式Hopkinson压杆装置间接测量混凝土材料动态应力-应变曲线存在的问题。试验分析了材料不均匀性和撞击端面接触不均匀对应变计记录信号的影响。在此基础上,用应变计直接测量应变法得到了无骨料钢纤维增强混凝土的两个应变率下的应力-应变曲线,并与传统方法的结果进行了分析比较。新方法适用于损伤演化较小的初始阶段,可以获得更可靠的加载应力-应变曲线。随着损伤的加剧,产生较大的随机应变,导致新方法的失效。

In this paper,experiments of using strain gauge to measure the dynamic stress strain curve of concrete directly were introduced.The problems of Split Hopkinson Pressure Bar(SHPB) technique used for measuring dynamic stress strain curve of concrete were discussed.The influences of material′s non uniform and uneven impact surfaces were analyzed by experiments.With this understanding,the dynamic stress strain curves of steel fiber reinforced concrete without coarse aggregate under two strain rates were obtained by the direct measurement method of strain gauge.The results from the present method and traditional SHPB technique were compared. In the initial stage with cell damage evolution, the present method is better than the traditional one. More reliable loading-stage of the stress-strain curve can be got by the present method. As the increasing damage engenders large random strain, it led to failure.