Figure 1

The trousers configuration: side (a) and top (b) schematics of the experiment. The sheet is pulled from the three strips as shown by the arrows. The strips are deflected by freely rotating cylinders and then rolled over two cylinders entrained by a continuous motor. (c) After the tears have converged, the central strip has a tonguelike shape, described by a curve $y(x)$.Reuse & Permissions

Figure 2

Crack paths in the trousers configuration. (a) Shape of the central strip: width $y$ as a function of longitudinal coordinate $x$; see Fig. 1c for definitions. The widths for a thickness of $90\mu \mathrm{m}$ were multiplied by 100 for clarity. The colors of the symbols correspond to different realizations. Power laws of exponents $2/3$ and 1 are shown for comparison. (b) Angle $\beta$ of inclination of the fracture surface with respect to the sheet surface (defined in inset) as a function of the longitudinal distance $x$, suggesting a transition around $x=5\mathrm{mm}$ from 45° to lower values. The initial distance between the two tears was $w=20\mathrm{mm}$ and the thickness had the value $h=50\mu \mathrm{m}$. (c) The curves in (a) were made nondimensional using the sheet thickness $h$ as a unit. Black and gray (red) symbols correspond to $h=50$ and $90\mu \mathrm{m}$, respectively.Reuse & Permissions

Figure 3

The peel-like configuration. (a) Schematic of the experiment. Two notches are initiated in a rectangular long sheet clamped along its lateral boundaries. The central strip is pulled horizontally at constant velocity until it detaches when the two tears converge. (b) Tonguelike shape of the detached strip, defined by $y(x)$.Reuse & Permissions

Figure 4

Crack paths in the peel-like configuration. (a) Shape of the central strip: width $y$ as a function of longitudinal coordinate $x$; see Fig. 3b for definitions. The widths for the values of the thickness 30 and $90\mu \mathrm{m}$ were divided and multiplied by 10, respectively, for clarity. The colors of the symbols correspond to different realizations. A power law of exponent $3/4$ is shown for comparison. (b) The curves in (a) were made nondimensional using the sheet thickness $h$ as a unit. Light gray (green), black, and dark gray (red) symbols correspond to $h=30$, 50, and $90\mu \mathrm{m}$, respectively.Reuse & Permissions