Acoustic emission from crumpling paper

Paul A. Houle and James P. Sethna

Physics Department, Cornell University, Ithaca, NY 14853-2501

cond-mat/9512055

ABSTRACT

From magentic systems to the crust of the earth, many physical systems that exhibit a multiplicity of metastable states emit pulses with a broad power law distrbution in energy. Digital audio recordings reveal that paper being crumpled, a system that can easily be held in hand, is such a system. Crumpling paper both using the traditional hand method and a novel cylinderical geometry uncovered a power law distribution of pulse energies spanning at least two decades: exponent 1.3-1.6. Crumpling initially 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 depdence on the grid spacing. Our results suggest that the pulse energy depends only weakly on the size of paper regions responsible for sound production.



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