Avalanche Behavior in Creep Failure of Disordered Materials

Area of Science:

• Materials Science
• Solid Mechanics
• Statistical Physics

Background:

• Disordered materials exhibit complex deformation behaviors under stress, including creep.
• Understanding the mechanisms of failure initiation and propagation is crucial for material design and safety.
• Stochastic processes and internal stress interactions play significant roles in material failure.

Purpose of the Study:

• To develop a mesoscale elastoplastic model for creep in disordered materials.
• To incorporate temperature-dependent stochastic activation and internal stress coupling.
• To investigate the role of damage in initiating catastrophic failure and strain localization.

Main Methods:

• Development of a generalized stochastic plasticity model.
• Inclusion of damage as a local strength that degrades with plastic strain.
• Analysis of collective avalanche dynamics and failure precursors.

Main Results:

• The model captures strain localization in a shear band and a finite-time singularity of the creep rate.
• Avalanche statistics near failure show a decreasing exponent approaching τ=1.5.
• The average avalanche rate follows an inverse Omori law, and interavalanche times match the ETAS model.

Conclusions:

• The developed model provides insights into the physics of creep and failure in disordered materials.
• The observed avalanche dynamics and statistical laws are analogous to earthquake phenomena.
• This work offers a framework for predicting material failure based on mesoscale deformation events.