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SUMMARY:The Ductility of 2D Cellular Solids: the Role of Imperfections - D
 r William Ronan\, CUED
DTSTART:20160212T140000Z
DTEND:20160212T150000Z
UID:TALK63280@talks.cam.ac.uk
CONTACT:Ms Helen Gardner
DESCRIPTION:The behaviour of foams\, lattices\, and other cellular materia
 ls in compression has received much attention in the literature and the re
 lationship between the microstructure of the cellular material and the mac
 roscopic response has been established both experimentally and theoretical
 ly. However\, the tensile response of such materials has not been explored
  and a number of experimentally observed phenomena are not clearly underst
 ood. In particular\, it is possible to compress an open-cell foam up to ve
 ry large strains (>50%) until densification. However\, in tension\, the sa
 me foam will fail at strains in the range 1% to 10%. It is well understood
  that open cell foams deform in compression by elastic and plastic bending
  (and buckling) of the foam struts. Since strut bending can accommodate la
 rge strains in compression\, such asymmetry between tension and compressio
 n is not expected.\n\n \n\nIn this talk\, I will first describe the behavi
 our of cellular materials in tension\, specifically where the solid materi
 al undergoes ductile failure (by necking)\, for different two-dimensional 
 foam geometries. The effect of relative density on the ultimate tensile st
 rength and the ductility is explained for the case of a perfect microstruc
 ture. Various defects\, such as plateau borders\, cell wall misalignments 
 and missing cell walls\, are introduced in order to elucidate the low obse
 rved ductility of foams.
LOCATION:Oatley Seminar Room\, Department of Engineering
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