Prof. Eliot Fried
McGill University, Montreal, Canadá
Data: 28/02/2011
Hora: 10h
Local: Centro de Tecnologia, Bloco G, sala 205
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Abstract: When a thin rectangular sheet is clamped along two opposing edges and stretched, its inability to accommodate the Poisson contraction near the clamps may lead to the formation of wrinkles with crests and troughs parallel to the axis of stretch. A variational model for this phenomenon is proposed. The underlying energy functional includes bending and membranal contributions. Motivated by work of Cerda, Ravi-Chandar, and Mahadevan, the functional is minimized subject to a global constraint on the area of the mid-surface of the sheet. Analysis of a boundary-value problem for the ensuing Euler–Lagrange equation shows that wrinkled solutions exist only above a threshold of the applied stretch. A sequence of critical values of the applied stretch, each element of which corresponds to a discrete number of wrinkles, is determined. Whenever the applied stretch is sufficiently large to induce more than one wrinkle, previously proposed scaling relations for the wrinkle wavelength and root-mean-square amplitude are confirmed. Comparisons with experimental measurements and numerical results indicate that the analytical results are remarkably robust.
Sobre o Palestrante:
Professor - Department of Mechanical Engineering
CRC Tier 1 - Interfacial and Defect Mechanics, Department of
Mechanical Engineering Associate Member - Department of Mathematics
and Statistics PhD California Institute of Technology, Applied Mechanics
MS California Institute of Technology, Applied Mathematics
AB University of California at Berkeley, Oriental Languages