X-ray tomography of a crumpled plastoelastic thin sheet

TL;DR

This study uses X-ray tomography to analyze the internal structure and evolution of crumpled aluminum foil, revealing how geometric fractal dimensions change with compression and how mass distribution becomes uniform, highlighting elastic dominance in deformation.

Contribution

It provides new insights into the internal structure of crumpled sheets, showing the transition of mass distribution and mapping the plastic regime to granular packing.

Findings

Fractal dimension increases with compression.

Mass distribution becomes more uniform during crumpling.

Interior resembles granular packing in the plastic regime.

Abstract

A three-dimensional X-ray tomography is performed to investigate the internal structure and its evolution of a crumpled aluminum foil. The upper and lower bounds of the internal geometric fractal dimension are determined, which increase with the compression. Contrary to the simulation results, we find that the mass distribution changes from being inhomogeneous to uniform. Corroborated with the evidence from previous experiments, these findings support the physical picture that the elastic property precedes the plastic one at dominating the deformation and mechanical response for all crumpled structures. We show that the interior of a crumpled ball at the plastic regime can be mapped to the compact packing of a granular system.