Oscillating Fracture Paths in Thin Brittle Sheets: When Geometry Rules Crack Propagation
نویسندگان
چکیده
We report a novel mode of quasi-static oscillatory crack propagation when a cutting tip of moderately large width is driven through a thin brittle polymer film (Roman [1] , Ghatak [2]). Experiments show that the amplitude and wavelength of the oscillatory crack paths scale linearly with the width of the cutting tip over a wide range of length scales but are independent of the width of the sheet and of the cutting speed. We propose a mechanism for this instability, based on the coupling between crack propagation and out-of-plane deformations of the film. This simple model (Audoly [3]), based on classical Griffith theory, shows that the propagation of crack in brittle thin sheets follows geometrical laws.
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