Instability cascades in crumpling mylar sheets follow a log-Poisson statistic.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Statistical Mechanics

Background:

• Aging in glassy materials is characterized by logarithmic evolution and power-law decay, differing from equilibrium materials.
• Nonequilibrium processes in disordered materials are often facilitated by activated events.
• Existing theories may not fully capture experimental observations in complex disordered systems.

Purpose of the Study:

• To investigate the aging process in crumpled Mylar sheets through acoustic emission measurements during buckling.
• To analyze the underlying statistical properties of buckling events in this nonequilibrium process.
• To determine if crumpling exhibits the log-Poisson property observed in other glassy materials.

Main Methods:

• Extensive computer simulations were used to generate long time-series data of buckling events.
• Acoustic emissions from Mylar sheets undergoing buckling under load were measured.
• Statistical analysis was performed to characterize the fluctuations and event distributions.

Main Results:

• Crumpling of Mylar sheets was identified as a log-Poisson process.
• The process is driven by increasingly rare, record-sized fluctuations.
• The material exhibits slow stiffening with a logarithmically growing length scale.

Conclusions:

• Crumpling in Mylar sheets demonstrates the log-Poisson property, aligning with other glassy materials.
• This finding provides a new perspective on the activated events governing nonequilibrium aging.
• The log-Poisson property can serve as a criterion to differentiate between theoretical models of glassy dynamics.