Universal behaviour in compressive failure of brittle materials.

Area of Science:

• Geophysics
• Materials Science
• Solid Mechanics

Background:

• Brittle failure limits compressive strength in rock and ice under rapid loading and low confinement.
• Ductile failure occurs at higher confinement or slower loading, crossing the brittle-ductile transition.
• Existing models for brittle failure localization include wing crack linkage or microcolumn buckling.

Purpose of the Study:

• To analyze a proposed mechanism for brittle failure localization in crystalline materials.
• To develop a quantitative model for brittle compressive strength and the brittle-ductile transition.
• To provide evidence for universal brittle failure processes.

Main Methods:

• Analysis of a bending-induced failure mechanism in microcolumns between secondary cracks.
• Development of a closed-form quantitative model based on measurable mechanical parameters.
• Comparison of model predictions with experimental data from various crystalline materials.

Main Results:

• The proposed mechanism explains brittle failure localization under low to moderate confinement.
• The developed model accurately predicts brittle compressive strength.
• Model predictions align with experimental data for the brittle-ductile transition across different materials.

Conclusions:

• The study presents a quantitative model for brittle failure based on microcolumn bending.
• The model demonstrates consistency with experimental data, supporting universal brittle failure processes.
• The findings highlight the broad applicability of the model to crystalline materials.