Creep failure in heterogeneous materials from the barrier landscape

Area of Science:

• Materials Science
• Statistical Physics
• Mechanics of Materials

Background:

• Materials under constant stress exhibit creep, a time-dependent deformation.
• Creep failure time is highly variable even for identical materials and applied stresses.
• Understanding creep behavior is crucial for material longevity and structural integrity.

Purpose of the Study:

• To investigate the statistical properties of creep failure in paper sheets.
• To compare experimental creep data with predictions from a fiber bundle model.
• To elucidate the underlying mechanisms governing creep failure predictability.

Main Methods:

• Experimental creep tests on paper sheets under constant load.
• Recording acoustic emission event times during creep.
• Simulating creep failure using a fiber bundle model in a disordered landscape.
• Analyzing event time data for statistical distributions and temporal dependencies.

Main Results:

• Experimental and simulation data exhibit sample-dependent history effects.
• Creep event times follow log-normal statistics and display non-Markovian behavior.
• A time-evolving power-law relationship was identified between acoustic emission event times and overall failure time.
• The development of the energy gap distribution during creep influences predictability.

Conclusions:

• Paper creep exhibits complex statistical behavior, including history effects and non-Markovian dynamics.
• A fiber bundle model can capture key aspects of creep failure in disordered materials.
• The energy gap distribution's evolution is a critical factor in understanding and predicting creep failure.
• These findings offer insights into the fundamental physics of material failure under sustained load.