Development of a split hopkinson pressure bar (SHPB) system for dynamic rock fracture testing with integrated electromagnetic radiation (EMR) monitoring

Predicting short-term precursors of underground structural failures is essential for minimizing human and economic losses. Among various sensing techniques, electromagnetic radiation (EMR) has shown potential as a non-contact method for detecting precursors to rock failure. While its behavior under quasi-static loading is relatively well understood, EMR characteristics under dynamic conditions remain unclear. To address this, a Split Hopkinson Pressure Bar (SHPB) system was developed with integrated EMR monitoring for dynamic rock fracture testing. Dynamic Brazilian tensile tests on granite successfully captured EMR signals near the fracture point. Fast Fourier Transform (FFT) analysis revealed peaks at 70–220 kHz, which are typical of rock failure, and additional high-frequency components at 0.7–1 MHz. These findings validate the system’s capability and provide new insights into EMR generation mechanisms under dynamic loading conditions.