Soft coring: how to get a clarinet out of a flute?

TL;DR

This paper investigates the morphogenetic process of coring in soft elastomers, revealing how friction influences the formation of clarinet-shaped cores when a cylindrical punch is inserted.

Contribution

It introduces a quantitative model combining fracture mechanics and large strain theory to explain the shape formation during coring in soft materials, emphasizing the role of friction.

Findings

Coring in soft elastomers produces clarinet-shaped cores with diameters smaller than the tool.

Friction plays a crucial role in the shape and size of the extracted core.

A simple model successfully explains the observed morphologies.

Abstract

Cutting mozzarella with a dull blade results in poorly shaped slices: the process occurs in a configuration so deformed as to yield unexpectedly curved surfaces. We study the rich morphogenetics arising from such process through the example of coring: when a thin cylindrical hollow punch is pushed into a soft elastomer, the extracted core is "clarinet-shaped", reaching diameters far smaller than those of the tool. With contributions from fracture mechanics and large strain theory, we build a simple yet quantitative understanding of the observed shapes, revealing the crucial role of friction.