Particle-based numerical modeling of AE statistics in disordered materials

We present some numerical simulations of AE due to damage propagation in disordered materials under compression and bending. To this purpose, the AE cumulative number, the time frequency analysis and the statistical properties of AE time series will be numerically simulated adopting the so-called particle method strategy (Cundall in Proceedings ISRM Symp., Nancy, France, vol. 2, pp. 129-136, 1971). The method provides the velocity of particles in a set simulating the behavior of a granular system and, therefore, is suitable to model the compressive wave propagation and acoustic emission (corresponding to cracking) in a solid body. The numerical simulations (Abe et al. in Pure Appl. Geophys. 161:2265-2277, 2004) correctly describe the compression test in terms of mean stress-strain response and crack pattern (Invernizzi et al. in Proceedings of the SEM annual conference, Society for Experimental Mechanics Inc., USA, SEM Annual Conference, Indianapolis, Indiana, USA, June 7-10, 2010). The size effects on the peak compressive strength and on the AE count are correctly reproduced. In addition, the amplitude distribution (b-value) and temporal evolution of AE events due to cracking, crucial for the evaluation of damage and remaining lifetime, were simulated and result in agreement with the experimental evidences.