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Dahmen, Karin A. Hubler, Alfred W. Dahmen, Karin A. Weismann, Michael Ceperley, David M. Tsekenis, Georgios 2012-05-22T14:34:27Z 2013-01-09T15:47:31Z 2012-05-22T14:34:27Z 2013-01-09T15:47:31Z 2014-07-09T10:00:49Z 2012-05 2012-05-22 2012-05 Crystalline materials deform in an intermittent way with slip-avalanches that are power-law distributed. In this work we study plasticity as a pinning-depinning phase transition employing a discrete dislocation dynamics (DDD) model and a phase eld crystal (PFC) model in two dimensions. Below a critical ( ow) stress, the dislocations are pinned/jammed within their glide plane due to long-range elastic interactions and the material exhibits plastic response. Above this critical stress the dislocations are mobile (the depinned/ unjammed phase) and the material constantly ows. We employ discrete dislocation dynamics to resolve the temporal pro les of slip-avalanches and extract the nite-size scaling properties of the slip-avalanche statistics, going beyond gross aggregate statistics of slip avalanche sizes. We provide a comprehensive set of scaling exponents, including the depinning exponent . Our work establishes that the dynamics of plasticity, in the absence of hardening, is consistent with the mean eld interface depinning universality class, even though there is no quenched disorder. We also use dislocation dynamics and scaling arguments in two dimensions to show that the critical stress grows with the square root of the dislocation density (Taylor's relation). Consequently, dislocations jam at any density, in contrast to granular materials, which only jam above a critical density. Finally, we utilize a phase eld crystal model to extract the size, energy and duration distributions of the avalanches and show that they exhibit power law behavior in agreement with the mean eld interface depinning universality class. Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2012-03-02T20:35:35Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 tsekenis_georgios.pdf: 3699694 bytes, checksum: 7ef99991db1547f779cb087e05bad04a (MD5) Made available in DSpace on 2012-05-22T14:34:27Z (GMT). No. of bitstreams: 1 tsekenis_georgios.pdf: 3699694 bytes, checksum: 7ef99991db1547f779cb087e05bad04a (MD5) Item reinstated by Sarah Shreeves (sshreeve@illinois.edu) on 2012-05-22T14:34:27Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 tsekenis_georgios.pdf: 3699694 bytes, checksum: 7ef99991db1547f779cb087e05bad04a (MD5) Restriction data tranferred 2014-07-01T11:10:08-05:00 Original Data Group with Access Administrator Release Date: 2014-07-09 09:47:35 UTC Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system Item withdrawn by Sarah Shreeves (sshreeve@illinois.edu) on 2012-05-22T14:37:36Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 3 SUBMISSION_LOG.csv: 11802 bytes, checksum: d304749086514dbaa5c74a403516b9cb (MD5) MODS.xml: 4831 bytes, checksum: 0b30d3de34bc481800b30a18934ae6c6 (MD5) TSEKENIS-DISSERTATION.pdf: 3699694 bytes, checksum: 7ef99991db1547f779cb087e05bad04a (MD5) Made available in DSpace on 2013-01-09T15:47:31Z (GMT). No. of bitstreams: 4 TSEKENIS-DISSERTATION.pdf: 3699694 bytes, checksum: 7ef99991db1547f779cb087e05bad04a (MD5) license.txt: 4067 bytes, checksum: 046d396ee310661b6d92572a1c69532c (MD5) MODS.xml: 4831 bytes, checksum: 0b30d3de34bc481800b30a18934ae6c6 (MD5) SUBMISSION_LOG.csv: 11802 bytes, checksum: d304749086514dbaa5c74a403516b9cb (MD5) Previous issue date: 2012-05-22 Item marked as restricted to the 'Administrator' Group (id=1) by William Ingram (wingram2@illinois.edu) on 2013-01-09T15:47:35Z Item is restricted until 2014-07-09T14:47:35Z Item moved by William Ingram (wingram2@illinois.edu) on 2013-9-01T09:53:13Z Item was at handle 123456789/506 (copy withdrawn) Limited Restriction Lifted for Item 35745 on 2014-07-09T10:00:49Z. application/pdf http://hdl.handle.net/2142/35323 en Copyright 2012 Georgios Tsekenis critical phenomena phase transition dislocation plasticity simulation scaling deformation phase field crystal discrete dislocation dynamics Plasticity as a depinning phase transition text Physics 1244 Physics 0240 University of Illinois at Urbana-Champaign Dissertation Ph.D. PHD:Physics -UIUC 10KS0240PHD