平板撞击下C30混凝土中冲击波的传播特性

采用1级气炮加载技术和锰铜应力计多点测试技术,开展了C30混凝土在平板撞击条件下的冲击压缩实验研究。基于锰铜应力计实测的应力波形,研究了混凝土中冲击波的传播特性,结果显示冲击波的应力峰值随传播距离呈现明显的衰减特性,衰减过程可分为2个阶段。在早期阶段,卸载波没有赶上前面传播的冲击波,冲击波应力峰值衰减较慢,主要是混凝土材料的本构粘性效应所引起的;而后期阶段应力峰值的快速衰减则归因于混凝土材料的本构粘性效应、后续的来自飞片自由面的反射波追赶卸载、边侧稀疏波卸载及波传播的几何弥散效应的共同作用;另外,冲击波在混凝土中传播的升时也随着传播距离逐渐增大,即由强间断波逐渐转化为弱间断波。

Shock wave propagation characteristics in C30 concrete under plate impact loading

Shock compression experiments were performed on C30 concrete by using the one-stage light-gas gun. The stress profiles at the different distances were measured by employing in-material manganin stress gauges. Based on the measured stress profiles, the shock wave attenuation characteristics in the C30 concrete samples were investigated. The shock stress peak took on transparent attenuation characters and the shock pressure attenuation process was divided into two phases. In phase 1, the reflected rarefaction wave did not catch up with shock wave and the slow attenuation of the shock pressure was attributed to the constitutive viscosity of concrete materials only. In phase 2, the quick attenuation of the shock pressure was caused by the sum of the constitutive viscosity, reflected rarefaction wave, edge rarefaction wave and geometrical expansion. On the other hand, the rise time of shock wave increased with the propagation distance, which was the other typical characteristic of shock pressure related to the constitutive viscosity of concrete materials.