Acoustic Emission from crumpling paper

TL;DR

This study demonstrates that crumpling paper produces a broad power law distribution of acoustic pulse energies, revealing universal features of systems with metastable states across different crumpling methods.

Contribution

It uncovers a consistent power law distribution of acoustic emissions during crumpling, regardless of crumpling method or paper size, highlighting universal behavior in such systems.

Findings

Pulse energies follow a power law distribution with an exponent of 1.3 - 1.6.

No systematic variation in energy distribution over time or sheet size.

Weak crumpling shows little dependence on grid spacing or region size.

Abstract

From magnetic systems to the crust of the earth, many physical systems that exibit a multiplicty of metastable states emit pulses with a broad power law distribution in energy. Digital audio recordings reveal that paper being crumpled, a system that can be easily held in hand, is such a system. Crumpling paper both using the traditional hand method and a novel cylindrical geometry uncovered a power law distribution of pulse energies spanning at least two decades: (exponent 1.3 - 1.6) Crumpling initally flat sheets into a compact ball (strong crumpling), we found little or no evidence that the energy distribution varied systematically over time or the size of the sheet. When we applied repetitive small deformations (weak crumpling) to sheets which had been previously folded along a regular grid, we found no systematic dependence on the grid spacing. Our results suggest that the pulse energy depends only weakly on the size of the paper regions responsible for sound production.