Improved peridynamic model and its application to crack propagation in rocks

Area of Science:

• Geomechanics
• Computational Mechanics
• Materials Science

Background:

• Conventional bond-based peridynamics (BB-PD) models struggle to simulate the strain hardening/softening behavior and differing fracture mechanisms of rocks under tension and compression.
• Existing models do not adequately represent the heterogeneity inherent in rock materials.

Purpose of the Study:

• To propose an improved BB-PD model capable of simulating complex rock fracture phenomena, including heterogeneity and distinct tensile/compressive failure modes.
• To analyze crack propagation, wing crack formation, and crack aggregation under various conditions.

Main Methods:

• Development of an improved BB-PD model with different fracture criteria for tensile and compressive loading stages.
• Incorporation of a Weibull distribution for critical failure conditions to model rock heterogeneity.
• Simulation of crack propagation in intact and flawed rock specimens under compressive loading.
• Investigation of wing crack propagation influenced by inclination angle and length.
• Analysis of crack aggregation modes under varying rock bridge inclination angles.

Main Results:

• The improved BB-PD model successfully simulated crack propagation and verified against laboratory tests.
• The study analyzed the influence of inclination angle and length on wing crack propagation.
• Eight distinct crack aggregation modes were identified and their occurrence conditions analyzed.

Conclusions:

• The enhanced BB-PD model effectively simulates rock crack propagation and coalescence, demonstrating wide applicability in rock fracture simulations.
• The model's ability to incorporate material heterogeneity and distinct failure criteria enhances its predictive power for complex geological materials.