BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Shear band dynamics - Davide Bigoni (University of Trento)
DTSTART:20190815T153000Z
DTEND:20190815T160000Z
UID:TALK128638@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:When a ductile material is subject to severe strain\, failure 
 is preluded by the emergence of shear bands\, which initially nucleate&nbs
 p\;&nbsp\;in&nbsp\; a&nbsp\; small&nbsp\; area\,&nbsp\; but&nbsp\; quickly
 &nbsp\; extend&nbsp\; rectilinearly&nbsp\; and&nbsp\; accumulate&nbsp\; da
 mage\,&nbsp\; until&nbsp\; they&nbsp\; degenerate&nbsp\; into&nbsp\; fract
 ures.&nbsp\;&nbsp\;Therefore\, research on shear bands yields a fundamenta
 l understanding of the intimate rules of failure\, so that it may be impor
 tant&nbsp\;in the design of new materials with superior mechanical perform
 ances.A shear band of finite length\, formed inside a ductile material&nbs
 p\;at a certain stage of a continued homogeneous strain\, provides&nbsp\; 
 a&nbsp\; dynamic&nbsp\; perturbation to an incident wave field\, which str
 ongly&nbsp\;influences the dynamics of the material and affects&nbsp\; its
 &nbsp\; path&nbsp\; to&nbsp\; failure.&nbsp\; The&nbsp\; investigation&nbs
 p\; of&nbsp\; this&nbsp\; perturbation&nbsp\; is&nbsp\; presented&nbsp\;&n
 bsp\;for&nbsp\; a&nbsp\; ductile&nbsp\; metal\,&nbsp\; with&nbsp\; referen
 ce&nbsp\; to&nbsp\; the&nbsp\; incremental mechanics of a material obeying
  the J2&ndash\;deformation theory of plasticity.&nbsp\;The treatment origi
 nates from the derivation of integral representations relating the increme
 ntal mechanical fields at every point of&nbsp\;the medium to the increment
 al&nbsp\; displacement&nbsp\; jump&nbsp\; across&nbsp\; the&nbsp\; shear&n
 bsp\; band&nbsp\; faces\,&nbsp\; generated&nbsp\; by&nbsp\; an&nbsp\; impi
 nging&nbsp\; wave.&nbsp\; The&nbsp\; boundary&nbsp\;&nbsp\;integral&nbsp\;
  equations are numerically approached through a collocation technique\, wh
 ich keeps into account the singularity at the shear band&nbsp\;tips and pe
 rmits the analysis of an incident wave impinging a shear band. It is shown
  that the presence of the shear band induces a resonance\,&nbsp\;visible i
 n the incremental displacement field and in the stress intensity factor at
  the shear band tips\, which promotes shear band growth.&nbsp\;Moreover\, 
 the waves scattered by the shear band are shown to generate a fine texture
  of vibrations\, parallel to the shear band line and&nbsp\;propagating at 
 a long distance from it\, but leaving a sort of conical shadow zone\, whic
 h emanates from the tips of the shear band [1\,2].<br>References<br>[1] Gi
 arola\, D.\, Capuani\, D. Bigoni\, D. (2018) The dynamics of a shear band.
  J. Mech. Phys. Solids\, 112\, 472-490.<br>[2] Giarola\, D.\, Capuani\, D.
  Bigoni\, D. (2018) Dynamic interaction of multiple shear bands. Scientifi
 c Reports 8 16033
LOCATION:Seminar Room 1\, Newton Institute
END:VEVENT
END:VCALENDAR