Discrete modeling of acoustic emission and fracture process zone in quasi-brittle rocks

Acoustic emission (AE) testing serves as a widely employed non-destructive technique for examining the behaviors of rocks under stress, with a particular focus on understanding the characteristics of the fracture process zone (FPZ). This paper investigates this phenomenon by conducting a numerical study using the two-dimensional discrete element method to simulate a three-point bending test with a center notch. An innovative displacement-softening contact law is incorporated to monitor the energy dissipation during bond damage and breakage. Additionally, the paper investigates the variation of AE energy levels corresponding to different loading stages, shedding light on intrinsic FPZ properties. The study further endeavors to categorize AE events based on their energy levels, showcasing the potential of the proposed model in capturing various FPZ characteristics. The simulation results affirm the model's capability to represent diverse FPZ behaviors, providing valuable insights for the calibration of numerical models for quasi-brittle rocks. This study lays the groundwork for potential advancements in predicting the behavior of rock formations by offering essential numerical evidence supporting the utilization of the proposed model.