Fig. 2: Experimental results for cutting tests.

Three cutting mechanisms---adhesion-dominated, adhesion- & friction-dominated, and damped—are exemplified with gelatin hydrogel, elastomer, and meat-based samples. a–c.1 Cutting force versus indentation curves. Ten repetitions are performed under the same test conditions. a–c.2 Images of the surface of the samples during the indentation and the cutting regimes. The images correspond to the following values of displacement: for the hydrogel, 2.70 mm, 5.24 mm, 6.18 mm, and 14.14 mm; for the elastomer, 0.62 mm, 1.56 mm, 2.29 mm, and 14.14 mm; and for the meat-based food material, 6.24 mm, 9.76 mm, 10.40 mm, and 14.14 mm. a–c.3 Surface engineering strain fields—defined according to Method 4.3—for one of the experimental repetitions (one with a force—displacement curve close to the mean one is selected). Three stages are analyzed, i.e., two before cutting onset—the second one at the end of the initial indentation—and one after the onset of cutting. The three stages correspond to the following values of displacement: for the hydrogel, 2.7 mm, 4.19 mm, and 6.17 mm; for the elastomer, 0.62 mm, 1.56 mm, and 2.29 mm; and for the meat-based sample, 4.80 mm, 9.76 mm, and 10.71 mm.