3D DEM modelling of acoustic emission in concrete: Insights into elastic waves initiated by microcracks.

In this paper, 3-point bending concrete beams were investigated through a combination of experimental and numerical analyses. Initially, laboratory tests were conducted to observe the formation and propagation of cracks using acoustic emission (AE) and digital image correlation (DIC) techniques. The experimental results obtained were then compared with a numerical study. The widely used discrete element method (DEM), implemented with the open-source code YADE, was employed. The primary objective was numerically reproducing the acoustic emission experiment. The model was fully 3D. During the entire test, the accelerations of 4 sensors were monitored, mirroring the experimental setup. The energy released during the damage process was quantified, and both cumulative energy and local jumps were directly compared. Furthermore, energy measurements were correlated with stress curves to explore their interdependencies. The numerical model, along with the experimental measurements, successfully detected signals from the sensors, indicating the occurrence of microcracking in the specimen before reaching peak load and failure.