Research on the Dynamic Mechanical Properties and Energy Dissipation Rules of Gradient Materials

In engineering practice, the strength of layered rock often changes in a gradient manner, and the failure mode and strength under dynamic loads of strength gradient composites are important indicators for evaluating their mechanical properties. The Split Hopkinson Pressure Bar (SHPB) technology can measure the material’s constitutive relationship under a fixed strain rate, which is one of the basic means of dynamic mechanics testing. This article uses the SHPB device to conduct dynamic compression tests on sandstone gradient rock, studies its dynamic mechanical properties, and combines the DIC method to study the deformation field and strain field of the test piece, analyzing the dynamic failure mode of strength gradient composites under different impact speeds. By introducing the concept of equivalent wave impedance, it systematically expounds the impact of the impedance ratio in gradient composites and the length of incident waves on the transmission coefficient.