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SUMMARY:Analytical homogenization estimates for the transient and steady-s
 tate response of elasto-viscoplastic polycrystals - Shuvrangsu Das\, CUED
DTSTART:20201030T143000Z
DTEND:20201030T150000Z
UID:TALK151744@talks.cam.ac.uk
CONTACT:Hilde Hambro
DESCRIPTION:In this work\, we make use of analytical homogenization method
 s to develop multiscale models for the macroscopic response and field stat
 istics of elasto-viscoplastic polycrystals in the transient and steady-sta
 te regimes.\n\nFirst\, we develop homogenization models for the steady-sta
 te response of porous polycrystals composed of large randomly distributed 
 pores in a fine-grained polycrystalline matrix\, with grains described by 
 crystal viscoplasticity. The model is then used to estimate the effects of
  microstructure on the macroscopic response of sea ice. The key finding he
 re is that the brine-air inclusions induce macroscopic compressibility\, w
 hich is significantly affected by the porosity\, pore geometry\, and cryst
 allographic texture of polycrystalline ice. Finally\, we obtain homogeniza
 tion estimates for the transient response of polycrystals with Maxwell-typ
 e elasto-viscoplastic grains\, exhibiting discrete relaxation spectra (sho
 rt memory). However\, their interaction leads to a continuous relaxation s
 pectrum for the macroscopic response (long memory). To capture the elasto-
 viscoplastic interaction of the grains\, and the associated long-memory ef
 fects\, we develop differential variational estimates for elasto-viscoplas
 tic polycrystals.  We find that the long-memory effects increase with the 
 anisotropy and nonlinearity of the viscoplastic response of the grains and
  that these effects are correlated with rapid changes in the inter- and in
 tra-granular field fluctuations. \n
LOCATION:zoom 853 4440 7455 - for password email  hh463@cam.ac.uk 
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