Oscillatory fracture path in thin elastic sheet

TL;DR

This paper reports a new oscillatory crack propagation mode in thin brittle polymer films, characterized by amplitude and wavelength scaling linearly with the cutting tip width, explained by a geometric model.

Contribution

It introduces a novel oscillatory crack propagation mode in thin elastic sheets and provides a geometric model explaining the phenomenon.

Findings

Oscillatory crack path is reproducible in thin brittle polymer films.

Amplitude and wavelength scale linearly with cutting tip width.

The phenomenon is independent of sheet width and cutting speed.

Abstract

We report a novel mode of oscillatory crack propagation when a cutting tip is driven through a thin brittle polymer film. The phenomenon is so robust that it can easily be reproduced at hand (using CD packaging material for example). Careful experiments show that the amplitude and wavelength of the oscillatory crack path scale lineraly with the width of the cutting tip over a wide range of lenghtscales but are independant of the width of thje sheet and the cutting speed. A simple geometric model is presented, which provides a simple but thorough interpretation of the oscillations.