Localized and extended deformations of elastic shells - Ashkan Vaziri & L. Mahadevan, Early Edition PNAS

Ashkan Vaziri's picture

The dried raisin, the crushed soda can, and the collapsed bicycle inner tube exemplify the nonlinear mechanical response of naturally curved elastic surfaces with different intrinsic curvatures to a variety of different external loads. To understand the formation and evolution of these features in a minimal setting, we consider a simple assay: the response of curved surfaces to point indentation. We find that for surfaces with zero or positive Gauss curvature, a common feature of the response is the appearance of faceted structures that are organized in intricate localized patterns, with hysteretic transitions between multiple metastable states. In contrast, for surfaces with negative Gauss curvature the surface deforms nonlocally along characteristic lines that extend through the entire system. These different responses may be understood quantitatively by using numerical simulations and classified qualitatively by using simple geometric ideas. Our ideas have implications for the behavior of small-scale structures.

Please see the attached paper and online supplementary materials for further information. I hope you find the work interesting.


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Vaziri and Mahadevan-PNAS2008.pdf1.17 MB
Marino Arroyo's picture

polyhedral deformations in carbon nanotubes

Dear Ashkan, 

Very interesting paper! Related to some of your comments in the paper, we actually have found and described polyhedral deformations in carbon nanotubes, and have characterized the effective nonlinear structural response in this regime. These are described in 

Arias and Arroyo, PRL 100:085503 (2008)

Arroyo and Arias, JMPS, 56(4) (2008)

Arroyo and Belytschko, PRL 91:215505 (2003)     

 

 

  

 

Best regards 

 Marino  

 

 

-- Marino Arroyohttp://www-lacan.upc.es/arroyo/Universitat Politecnica de CatalunyaCampus Nord, C2-204Jordi Girona 1-3Barcelona, 08034Tel: +34 93 4011805Fax: +34 93 4011825