Flow Localization in Thermal Viscoplastic Materials
{'Code': '07030000', 'Directorate': {'Abbreviation': 'ENG', 'LongName': 'Directorate For Engineering'}, 'Division': {'Abbreviation': 'CMMI', 'LongName': 'Div Of Civil, Mechanical, & Manufact Inn'}}
{'SignBlockName': 'Dianne McCormick', 'PO_EMAI': None, 'PO_PHON': None}
The primary goal of this study is to further develop using analytical           and computational procedures, the understanding of the mechanisms               responsible for shear strain localization during the plastic                    deformation of both metals and polymers, as well as to improve the              accuracy and efficiency of the computational algorithms used to                 simulate shear band formation.  The so-called "thermo-mechanical                mechanism" is primarily considered the mechanism responsible for flow           localization at high rates of deformation.  Efficient numerical                 algorithms are developed for the integration of the full tensorial form         of strain-rate dependent constitutive relations.  These numerical               algorithms specifically account for strain softening phenomena by               either thermal softening or by "fractures in progress" due to void              growth or microcrack formation.  Two main stages of the deformation are         considered; namely, the pre-initiation regime (I) and the post-                 initiation regime (II).  The study of regime I is concerned with the            necessary and sufficient conditions for the onset of shear bands and            the influence of several factors on the critical strain level at which          bands may initiate.  Such factors include heat conduction, thermal              softening, strain rate sensitivity, elasticity, imperfections, and              boundary conditions.  The study of regime II is concerned with the              phenomenon of band narrowing and the loss of local adiabaticity that            leads to a quasi-steady-state condition within the bands.  A model is           constructed to derive the characteristic band thickness and the                 characteristic band spacing.  Further, the change in material                   properties is accounted for within the bands, and the influence of any          local phase transformation on the macroscopic behavior of the body is           analyzed.
{'FirstName': 'Tarek', 'LastName': 'Shawki', 'PI_MID_INIT': 'G', 'PI_SUFX_NAME': None, 'PI_FULL_NAME': 'Tarek G Shawki', 'EmailAddress': 't-shawki@uiuc.edu', 'PI_PHON': '2173337131', 'NSF_ID': '000110410', 'StartDate': '06/01/1987', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'University of Illinois at Urbana-Champaign', 'CityName': 'URBANA', 'ZipCode': '618013620', 'PhoneNumber': '2173332187', 'StreetAddress': '506 S WRIGHT ST', 'StreetAddress2': None, 'CountryName': 'United States', 'StateName': 'Illinois', 'StateCode': 'IL', 'CONGRESSDISTRICT': '13', 'CONGRESS_DISTRICT_ORG': 'IL13', 'ORG_UEI_NUM': 'Y8CWNJRCNN91', 'ORG_LGL_BUS_NAME': 'UNIVERSITY OF ILLINOIS', 'ORG_PRNT_UEI_NUM': None}
{'Name': None, 'CityName': None, 'StateCode': None, 'ZipCode': None, 'StreetAddress': None, 'CountryCode': None, 'CountryName': None, 'StateName': None, 'CountryFlag': None, 'CONGRESSDISTRICT': None, 'CONGRESS_DISTRICT_PERF': '""'}
{'Code': '1441', 'Text': 'MECHANICS'}
{'url': 'https://www.nsf.gov/awardsearch/download?DownloadFileName=1987&All=true', 'xml': '8709299.xml'}