A Particle-Based Cohesive Crack Model for Brittle Fracture Problems.

Area of Science:

• Computational mechanics
• Materials science
• Fracture mechanics

Background:

• Modeling fracture in materials is computationally challenging.
• The discrete element (DE) method offers a robust approach for simulating fracture.
• Existing DE models distinguish between solid (connective) and particulate (contact) phases.

Purpose of the Study:

• To develop a DE particle-based cohesive crack model for simulating mixed-mode fracture in brittle materials.
• To model the transition of material from a solid to a particulate phase during fracture.
• To bridge the microscale gap between DE connective and contact models.

Main Methods:

• A cohesive crack model is implemented at inter-particle bonds within the DE connective model.
• A potential formulation from the cohesive zone method is adopted.
• A linear softening traction-separation law governs fracture initiation.

Main Results:

• The model successfully simulates the transition from solid to particulate phases during fracture.
• Validation against standard fracture tests shows good agreement with analytical solutions.
• Numerical results for an impact-loaded concrete beam surpass finite element method accuracy compared to experimental data.

Conclusions:

• The particle-based cohesive crack model effectively describes material separation from solid to particulate states.
• The model provides a microscale link between DE connective and contact mechanics.
• It demonstrates superior predictive capability for impact fracture scenarios compared to traditional methods.