Multiple-length-scale elastic instability mimics parametric resonance of nonlinear oscillators

Spatially confined rigid membranes reorganize their morphology in response to the imposed constraints. A crumpled elastic sheet presents a complex pattern of random folds focusing the deformation energy while compressing a membrane resting on a soft foundation creates a regular pattern of sinusoidal wrinkles with a broad distribution of energy. Here, we study the energy distribution for highly confined membranes and show the emergence of a new morphological instability triggered by a period-doubling bifurcation. A periodic self-organized focalization of the deformation energy is observed provided an up-down symmetry breaking, induced by the intrinsic nonlinearity of the elasticity equations, occurs. The physical model, exhibiting an analogy with parametric resonance in nonlinear oscillator, is a new theoretical toolkit to understand the morphology of various confined systems, such as coated materials or living tissues, e.g., wrinkled skin, internal structure of lungs, internal elastica of an artery, brain convolutions or formation of fingerprints. Moreover, it opens the way to new kind of microfabrication design of multiperiodic or chaotic (aperiodic) surface topography via self-organization.Comment: Submitted for publicatio

Extremely robust and conformable capacitive pressure sensors based on flexible polyurethane foams and stretchable metallization

Microfabricated capacitive sensors prepared with elastomeric foam dielectric films and stretchable metallic electrodes display robustness to extreme conditions including stretching and tissue-like folding and autoclaving. The open cellular structure of the elastomeric foam leads to significant increase of the capacitance upon compression of the dielectric membrane. The sensor sensitivity can be adjusted locally with the foam density to detect normal pressure in the 1 kPa to 100 kPa range. Such pressure transducers will find applications in interfaces between the body and support surfaces such as mattresses, joysticks or prosthetic sockets, in artificial skins and wearable robotics. (C) 2013 AIP Publishing LLC

L'Elastica, de Leonhard Euler à nos jours !

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Self-Cleaning Surfaces Prepared By Microstructuring System

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Multiple lengthscales elastic instability via period-doubling bifurcations

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Multiple-length-scale elastic instability mimics parametric resonance of nonlinear oscillators

info:eu-repo/semantics/publishe