An extended peridynamic bond-based constitutive model for simulation of crack propagation in rock-like materials.

The stress of rock-like materials first increases and then decreases with an increase in the strain, and finally become damaged under tensile or compressive loads. It is not suitable to use the traditional bond-based peridynamics model to simulate the crack propagation of rock-like materials. Based on the bond-based peridynamics theory, a constitutive model has here been proposed that can reflect the characteristic of the stress with an increase in strain (i.e., that the stress of the rock-like materials first increases and then decreases, and finally fails). This makes up for the weakness with the traditional bond-based peridynamics theory, which fails to reflect the stress-strain change in rock-like materials. The strain energy density of the proposed constitutive model of rock-like materials has been derived and compared against the classical elasticity theory to obtain the model constants with respect to the elasticity moduli for plane stress conditions. Based on the here proposed constitutive model for rock-like materials, a numerical solution program for rock-like materials has been written using the Fortran language. For different loading conditions, the crack propagation process for an intact specimen has been simulated and compared with experimental results. This was also the situation for a specimen with a pre-existing flaw, a single non-straight flaw, and with three pre-existing flaws for plane stress conditions. The numerical simulation results were in good agreement with the corresponding experimental results. By using this proposed constitutive model, it was possible to simulate and predict the mechanical properties of rock-like materials, and the process of crack initiation, propagation, and coalescence under different loading conditions. The results from the present study can thus provide a reference for practical engineering. [ABSTRACT FROM AUTHOR]