Abstract
We study multiple tearing of a thin, elastic, brittle sheet indented with a rigid cone. The cracks initially prepared symmetrically propagate radially for . However, if the radial symmetry is broken and fractures spontaneously intertwine along logarithmic spiral paths, respecting order rotational symmetry. In the limit of very thin sheets, we find that fracture mechanics is reduced to a geometrical model that correctly predicts the maximum number of spirals to be strictly 4, together with their growth rate and the perforation force. Similar spirals are also observed in a different tearing experiment (this time up to , in agreement with the model), in which bending energy of the sheet is dominant.
- Received 22 January 2016
DOI:https://doi.org/10.1103/PhysRevLett.116.165501
© 2016 American Physical Society