000015199 001__ 15199 000015199 005__ 20161115100214.0 000015199 04107 $$aeng 000015199 046__ $$k2016-08-21 000015199 100__ $$aRoman, Benoit 000015199 24500 $$aIntertwined spiraling crack path in perforated sheets 000015199 24630 $$n24.$$p24th International Congress of Theoretical and Applied Mechanics - Book of Papers 000015199 260__ $$bInternational Union of Theoretical and Applied Mechanics, 2016 000015199 506__ $$arestricted 000015199 520__ $$2eng$$aWhen a brittle sheet is indented by a rigid cone, a radial fracture pattern is usually observed (“petalling”). We show experimentally then the number n of cracks is smaller than 4, a spiraling pattern is observed instead of the petalling mode. In the limit of very thin and very brittle sheet, we do find solutions where the crack path are intertwined logarithmic spirals, and compute the corresponding perforation force. Both the geometry and the force agree well with experiments. 000015199 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb. 000015199 653__ $$a 000015199 7112_ $$a24th International Congress of Theoretical and Applied Mechanics$$cMontreal (CA)$$d2016-08-21 / 2016-08-26$$gICTAM2016 000015199 720__ $$aRoman, Benoit 000015199 8560_ $$ffischerc@itam.cas.cz 000015199 8564_ $$s96528$$uhttps://invenio.itam.cas.cz/record/15199/files/TS.SM05-3.05.pdf$$yOriginal version of the author's contribution as presented on CD, page 2048, code TS.SM05-3.05 . 000015199 962__ $$r13812 000015199 980__ $$aPAPER