Effects of the blade shape on the slicing of soft gels

Slicing soft gels with a knife is eased by rapidly sliding the blade along its edge. This common observation has been recently explained thanks to a model in which the split of the gel results from a failure occurring at a critical stress and consisting of the transformation of the solid gel into a liquid phase (Phys Rev Lett 125:038002, 2020). Here, the cutting process is shown to be independent of the yield criterion of the gel, and the model investigated further by considering the thickness and the shape of the blade. Features of the slicing process converge toward the zero-thickness limit as the sharpness of the blade increases. The model does predict that a thinner edge facilitates the cleavage. In addition, a symmetric cross section of the blade is found to be more efficient than a bevel.