混凝土类材料SHPB实验中确定应变率的方法

由于混凝土类材料在SHPB实验中很难实现恒应变率加载,为了确定非恒应变率加载下的实验数据所对应的应变率,本文中针对不同强度(C20,C45,C70)和不同钢纤维含量(0%,0.75%,1.50%,4.50%)的混凝土进行了SHPB实验。对实验得到的30组恒应变率加载下的数据进行了分析总结,结果表明:实验数据所对应的恒应变率与全段平均应变率之间存在一定的比值关系,从而混凝土类材料SHPB实验数据所对应的应变率可以采用全段平均应变率的1.38倍来表征。通过对比非恒应变率加载和恒应变率加载下得到的应力应变曲线,验证了该确定应变率方法的合理性,并指出较短恒应变率加载下实验数据对应的应变率直接采用短平台段对应的应变率来表征是不合理的。

A novel method for determining strain rate of concrete-like materials in SHPB experiment

In this paper, we performed SHPB experiments on concrete-like materials with different strengths (C20, C45, C70) and different steel fiber contents (0%, 0.75%, 1.50%, 4.50%) and analyzed the data drawn. The results showed that the constant strain rate corresponding to the experimental data was co-related with the whole-stage average strain rate to a certain degree and therefore the former could be determined by the 1.38 times of the latter. This method was verified as rational by the comparative analysis of the experimental data of non-constant strain rate with the experimental data of constant strain rate. It was also found that, at the constant strain rate in a relatively short loading time, it is unreasonable to characterize the strain rate corresponding to the experimental data using the constant strain rate corresponding to the short platform stage. In this case, the method proposed in this paper offers a good choice.