- Cutting and Slicing Weak Solids doi link

Auteur(s): Mora S., Pomeau Yves

(Article) Publié: Physical Review Letters, vol. 125 p. (2020)

Ref HAL: hal-02925886_v1
DOI: 10.1103/PhysRevLett.125.038002
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Dicing soft solids with a sharp knife is quicker and smoother if the blade is sliding rapidly parallel to its edge in addition to the normal squeezing motion. We explain this common observation with a consistent theory suited for soft gels and departing from the standard theories of elastic fracture mechanics relied on for a century. The gel is assumed to fail locally when submitted to stresses exceeding a threshold σ 1. The changes in its structure generate a liquid layer coating the blade and transmitting the stress through viscous forces. The driving parameters are the ratio U=W of the normal to the tangential velocity of the blade, and the characteristic length ηW=σ 1 , with η the viscosity of the liquid layer. The existence of a maximal value of U=W for a steady regime explains the crucial role of the tangential velocity for slicing biological and other soft materials.

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