SIMULATION OF THE FRACTURE OF HETEROGENEOUS MATERIALS UNDER CYCLIC LOADING

Fracture of heterogeneous materials under cycling loading is investigated by using a simple deterministic model. A material is simulated by an inhomogeneous two-dimensional square lattice. Characteristics of the fracture process are studied as functions of the amplitude of the strain factor Delta R and the loading period t(p); the durability of the material is also analyzed as a function of these parameters. It is shown that the degree of fracture in the system increases with Delta R for small t(p) and is practically independent of Delta R for large t(p). The fractal dimensionality remains constant under all conditions and is equal to D = 1.10 +/- 0.04. Fracture clusters at points of destruction of the material (percolation clusters) are anisotropic and their width-to-length ratio (the anisotropy parameter) averaged over all possible configurations is equal to delta = 0.18 +/- 0.10 (Delta E = 90). A power decrease in the elasticity modulus E of the system with an index tau = 0.39 +/- 0.17 is observed near the percolation threshold.