Cutting soft materials: how material differences shape the response

TL;DR

This study investigates how different soft materials respond to cutting, revealing material-dependent behaviors and providing a unified model that explains the underlying physics, with implications for surgical tools and food engineering.

Contribution

It introduces a combined experimental and computational approach to understand soft cutting mechanics across various materials, highlighting the roles of adhesion and viscous forces.

Findings

Material-dependent cutting behaviors observed

Adhesion and viscous forces dominate tangential stresses

Coulomb friction is negligible in soft cutting

Abstract

Cutting soft materials is a complex process governed by the interplay of bulk large deformation, interfacial soft fracture, and contact forces with the cutting tool. Existing experimental characterizations and numerical models often fail to capture the variety of observed cutting behaviors, especially the transition from indentation to cutting and the roles of dissipative mechanisms. Here, we combine novel experimental cutting tests on three representative materials-a soft hydrogel, elastomer, and food-based materials-with a coupled computational model that integrates soft fracture, adhesion, and frictional interactions. Our experiments reveal material-dependent cutting behaviors, with abrupt or smooth transitions from indentation to crack initiation, followed by distinct steady cutting regimes. The computational model captures these behaviors and shows that adhesion and viscous cohesive forces dominate tangential stresses, while Coulomb friction plays a negligible role due to low contact pressures. Together, these results provide new mechanistic insights into the physics of soft cutting and offer a unified framework to guide the design of soft materials, cutting tools, and cutting protocols, with direct relevance to surgical applications and the engineering of food textures optimized for mastication.