High-fidelity Acoustic Emission Sensing: From Sensor Design to Seismo-Mechanical Source Physics in Geological Materials

Rui Wu, State Key Laboratory of Intelligent Coal Mining and Strata Control, Beijing, China

Sunday 20th September

Course Description

Acoustic emission (AE) monitoring is a powerful experimental technique that captures transient elastic waves generated by rapid localized deformation and failure processes within geological materials, including microcrack initiation, propagation, and coalesce. These laboratory-scale acoustic signals share fundamental physical processes with seismic waves generated by natural earthquakes and anthropogenic earthquakes occurring across a wide range of spatial and temporal scales. Therefore, high-fidelity AE observations provide a unique opportunity to bridge laboratory experiments and coupled seismo-hydro-mechanical processes in the Earth’s crust.

However, traditional AE measurements are often limited by sensor capability to capture the full dynamics of fracture processes, uncertainties in quantitative signal calibration, and challenges in linking recorded signals to underlying rupture mechanisms. This course introduces recent advances in high-fidelity AE sensing technologies developed through multiphysics modeling, advanced calibration approaches, and their applications in revealing fracture and seismic source physics.

The course consists of two parts.

Part I: Multiphysics-based design and calibration of high-fidelity AE sensors

This part introduces how multiphysics modeling can be employed to design, optimize, and quantitatively calibrate piezoelectric AE sensors for high-fidelity measurements. Topics include:

• Electromechanical coupling and wave propagation in piezoelectric sensors;
• Contact mechanics and dynamic source characterization for sensor calibration;
• Absolute calibration methods and reconstruction of sensor transfer functions;
• Linking calibrated AE waveforms with quantitative seismic source characteristics.

Part II: Revealing fracture and seismo-mechanical source physics using advanced AE technologies

This part demonstrates how high-fidelity AE sensing technologies can provide new insights into damage evolution, rupture processes, and seismic energy release during geological failure processes. Two laboratory case studies will be presented, covering brittle tensile fracturing and fluid-driven shear fracturing processes in brittle rocks. Together, these examples illustrate how advanced AE observations can bridge laboratory-scale measurements with broader seismo-mechanical processes relevant to earthquakes, induced seismicity, energy extraction, and underground engineering.