On the Stress Fields in Inhomogeneous Media Determined by the Acoustic Emission Method

Fractal features of fracture centers in heterogeneous materials revealed by discrete element method

“…A more homogeneous sample 1 fails brittle with one crack forming at time t≈0.01 s. The more heterogeneous sample 2 demonstrates a significant irregularity in the time dependence of the fractal dimension of intervals and clearly identifies two fracture centers. This corresponds to the homogeneous (multifocal) nature of the destruction of samples heterogeneous in structure, [13, 20]. Because of the possibility of large deformation of grain boundaries due to the presence of low‐modulus bonds in sample 3, as well as their large diameter (0.6 mm), the process is significantly extended in time.…”

“…Time dependencies of the fractal dimension of intervals confirm the previously discovered point that the fracture is homogeneous (multifocal) in heterogeneous materials, and vice versa. This is a consequence of the fact that the homogeneity of the material leads to greater spatial heterogeneity of local inelastic stresses [13, 20].…”

“…Cylindrical samples with a diameter of 10 mm and a height of 20 mm were modeled. They were sized to enable comparison of modeling results with laboratory results, which had been obtained earlier on the equally‐sized samples [13]. The cylinders were filled with spherical particles of the same or different sizes and packed until a porosity of 0.35–0.37 was reached.…”

“…The considered model adequately describes some features of the destruction of heterogeneous materials in cases where the main processes occur along grain boundaries [13]. In particular, realistic loading diagrams reflecting the macroscopic equations of state for brittle and ductile materials were reproduced.…”