Sixth International Congress on Thermal Stresses, TS 2005, Vienna, May 26–29, 2005 Ernst Melan & Heinz Parkus Memorial Session MESOSCALE ANALYSIS OF SHEAR BANDS IN HIGH STRAIN RATE DEFORMATIONS OF TUNGSTEN/ NICKEL-IRON COMPOSITES R. C. Batra and B. M. Love Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA We analyze the initiation and propagation of adiabatic shear bands in a tungsten heavy alloy by modeling each constituent as a heat-conducting, microporous, isotropic, elastother- moviscoplastic material. The two constituents are assumed to be perfectly bonded to each other so that the temperature, heat flux, displacements, and surface tractions are continuous across an interface between a tungsten particulate and the nickel-iron matrix. Three differ- ent modes of deformation, namely plane strain tension=compression, plane strain shear, and axisymmetric tension=compression are analyzed. No other defects are introduced. It is found that contours of the rate of temperature rise and=or velocity and=or the specific energy dissipation rate rather than those of effective plastic strain delineate the shear banded regions. For the same volume fraction of particulates smaller diameter particulates enhance the formation of adiabatic shear bands. The time of initiation of an adiabatic shear band also depends upon the particulate arrangement. Keywords: Mesoscale analysis; Finite element solution; Thermoviscoplasticity; Microporous materials; Particulate composite; Tungsten heavy alloys An adiabatic shear band (ASB) is a narrow region, usually a few lm wide, of intense plastic deformation that forms in most materials deformed at high strain rates. Even though heat conduction plays a significant role during the development of an ASB, it is termed adiabatic since there is not enough time for the heat to be conducted away from the shear banded region. The analysis of ASBs is important because they pre- cede ductile fracture and play an important role in penetration problems. Even though the initiation, development and propagation of ASBs have been extensively Received 2 February 2005; accepted 9 February 2005. This work was partially supported by the NSF grant CMS0002849, the ONR grants N00014-98-1-0300 and N00014-03-MP-2-0131, the ARO grant DAAD19-01-1-0657 and the AFOSR MURI to Georgia Institute of Technology with a subcontract to Virginia Polytechnic Institute and State University. Views expressed in the paper are those of authors and not of funding agencies. Address correspondence to R. C. Batra, Department of Engineering Science and Mechanics, MC 0219, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA. E-mail: rbatra@ vt.edu 747 Journal of Thermal Stresses, 28: 747–782, 2005 Copyright # Taylor & Francis Inc. ISSN: 0149-5739 print/1521-074X online DOI: 10.1080/01495730590932724