Micro-mechanical fracture dynamics and damage modelling in brittle materials

Area of Science:

• Solid Mechanics
• Material Science
• Wave Propagation

Background:

• Brittle materials exhibit complex behaviors under dynamic loading.
• Micro-mechanical fracture dynamics are crucial for understanding material damage.
• Wave propagation phenomena are significantly influenced by material degradation.

Purpose of the Study:

• To investigate the relationship between wave propagation and material damage in brittle substances.
• To introduce a microscopic evolution index for linking micro-scale crack dynamics to macro-scale material response.
• To analyze the generation of shock waves due to coupled micro-macro scale processes.

Main Methods:

• Development of damage models based on micro-mechanical fracture dynamics.
• Formulation of a non-dimensional mathematical problem for wave propagation with damage.
• Introduction and analysis of the microscopic evolution index.
• Construction of a semi-analytical solution for the 1D wave propagation problem.

Main Results:

• A high microscopic evolution index (quasi-static micro, dynamic macro) can lead to loss of hyperbolicity and shock wave generation.
• Significant strain rate sensitivity was observed: pulse amplitude decreases with strain rate.
• At critical strain rates, the micro-scale model becomes rate-independent.
• Friction on micro-cracks plays a role in blast wave propagation modeling.

Conclusions:

• The microscopic evolution index effectively links micro- and macro-scale behaviors in damaged brittle materials.
• Understanding strain rate sensitivity is critical for predicting wave propagation and material failure.
• The study provides insights into shock wave regularization and the influence of friction on damage dynamics.