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SUMMARY:Large strain elastic response of auxetic foams - Seminar by Dr. Ja
 copo Ciambella - Dr. Jacopo Ciambella - Lecturer in Composites Engineering
  at the Advanced Composites Centre for Innovation and Science of the Unive
 rsity of Bristol
DTSTART:20140731T130000Z
DTEND:20140731T140000Z
UID:TALK53577@talks.cam.ac.uk
CONTACT:Stoyan Smoukov
DESCRIPTION:Auxetics are a broad class of material and structures mainly e
 xhibiting negative Poisson's ratio (NPR) behaviour. NPR indicates than a s
 olid expand in all directions when pulled along one\, behaving therefore i
 n a counterintuitive manner compared to "classical" solids.\nIn this semin
 ar I will present the description of NPR open cell foams produced using th
 e standard manufacturing techniques and modeled via a novel hyperelastic m
 aterial formulation based on an Ogden-type strain energy approach. When us
 ed as load bearing or energy absorption elements\, the foams are subjected
  to large deformations and nonlinear behaviour becomes important. From the
  modeling perspective several nonlinear elastic models have been formulate
 d in open literature\, some of them based on statistical distributions of 
 the density and mechanical properties of the unit cells along the compress
 ive direction.\nThese models are based on a kinematical map between the de
 formation of the cell ribs and the macroscopic strain. As such\, they have
  the major drawback of being dependent upon the particular foam structure 
 used for their development. Another approach is here adopted allowing the 
 auxetic foam to be modeled as a continuum solid. The evolution of the micr
 ostructure of the foam is investigated and it is shown that the main featu
 re observed in the experimental data can be accurately described by a isot
 ropic hyperelastic model with an Ogden-type strain energy function. The mo
 del can be easily implemented in a finite element code hus allowing more c
 omplex deformation patterns to be simulated.\n\nJacopo Ciambella is Lectur
 er in Composites Engineering at the Advanced Composites Centre for Innovat
 ion and Science of the University of Bristol. His interest on nonlinear vi
 scoelasticity of nano­ composites has origins from his PhD work undertake
 n at the University of Rome “La Sapienza” in cooperation with Bridgest
 one Technical Center Europe (2006-2010). His research also deals with micr
 o-macro modelling of multifunctional composites and energy absorbing compo
 site materials.
LOCATION:Goldsmiths 2 Lecture Theatre\, Materials Science and Metallurgy B
 uilding
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