The dynamic rheology of a complex granular material system strongly depends on the imposed stress state. However, drawing a clear physics based picture of dynamic granular flow is challenging due to the heterogeneous nature of granular materials, as well as the overwhelming difficulties in carrying out dynamic experiments. Here, pressure-shear plate impact (PSPI) is utilized to load a granular boron carbide ceramic in a multi-axial fashion with strain rates on the order of 10⁵ ${\mathrm{s}}^{-1}$ and pressure levels ranging from 1 to 3 GPa. Comparisons between the shear flow stresses and the superimposed normal stress indicate a strong pressure dependence in the constitutive response, along with an effective friction coefficient measured to be around 0.16. Both the normal and shear stress-strain relations are obtained. Granular boron carbide shows a highly compressible behavior with a significant amount of volume compaction achieved as the result of the large uniaxial normal strain. Due to the compaction, the estimated granular wave speed increases with density. Microstructure characterization of the deformed particles shows that fracture and amorphization are active deformation mechanisms besides the grain-grain frictional interactions and particle rearrangement. This study will contribute to the development of integrative modeling for behavior of granular boron carbide at ultra-high strain rates and confinement pressures.

复杂颗粒材料系统的动态流变学在很大程度上取决于施加的应力状态。然而，由于粒状材料的异质性以及进行动态实验的巨大困难，绘制清晰的基于物理原理的动态粒状流动图具有挑战性。在此，压剪板冲击（PSPI）被利用的10的数量级上与应变率加载粒状碳化硼陶瓷在多轴方式⁵ ${\mathrm{s}}^{-\mathrm{1个}}$压力范围为1至3 GPa。剪切流应力和叠加法向应力之间的比较表明，本构响应中的压力依赖性很强，并且测得的有效摩擦系数约为0.16。同时获得了法向和剪切应力-应变关系。碳化硼颗粒表现出高度可压缩的行为，并且由于大的单轴法向应变而实现了大量的体积压缩。由于压实，估计的颗粒波速度随密度增加。变形颗粒的微观结构表征表明，断裂和非晶化是除了晶粒间的摩擦相互作用和颗粒重排之外的主动变形机制。