The compressive strength of crumpled matter

Area of Science:

• Materials Science
• Mechanical Engineering
• Physics of Soft Matter

Background:

• Crumpling materials creates stiff, lightweight structures with potential engineering value.
• Current limitations in engineering applications stem from a lack of reliable structure-property relationships for crumpled materials.
• Existing theoretical models do not fully explain the mechanical behavior of crumpled sheets.

Purpose of the Study:

• To develop a predictive model for the mechanical response of crumpled materials under compression.
• To investigate the relationship between the substructure of crumpled materials and their mechanical properties.
• To enable the engineering use of crumpled materials by providing a trustworthy predictive framework.

Main Methods:

• Experimental compression testing of elastic and plastic polymer films in a crumpled state.
• Development and validation of an empirical model to predict force-displacement behavior.
• Direct measurement and analysis of substructures within the crumpled material.

Main Results:

• An empirical model accurately predicts the force response of crumpled sheets over 50 orders of magnitude.
• Experimental data deviates from recent theoretical predictions based on specific substructures.
• Direct substructure analysis reveals that bending in stretching ridges is the primary source of strength in both elastic and plastic crumples.

Conclusions:

• A simple, physically motivated empirical model reliably predicts the mechanical behavior of crumpled materials.
• The bending of stretching ridges, not previously emphasized, is key to the strength of crumpled structures.
• This predictive capability may unlock the engineering application of a wide range of crumpled materials.