Georgia Institute of Technology
Georgia Institute of Technology
Wright State University
Dr Moosbrugger's research focuses on plasticity and viscoplasticity of materials, including analytical/phenomenological modeling of nonproportional (biaxial), cyclic loading experiments, performing complex biaxial experiments, nonisothermal viscoplasticity model development for metals and thermomechanical behavior of semiconductor materials. Interests lie in macroscopic continuum mechanics, continuum micromechanics, and microstructural kinetics applied to constitutive equation development, fatigue life prediction and computational solid mechanics. This includes theoretical modeling using internal variable approaches at the micro- and macro-continuum levels as well as the interpretation and analysis of experimental results. Some projects are summarized below.
In conjunction with Dr. David Morrison, this work focuses on relationships between dislocation substructure and cyclic plasticity modeling. Numerous experiments have been performed on fine and course grain nickel and nickel single crystals and the dislocation substructures developed under constant plastic strain amplitude, cyclic loading have been characterized. Models have been developed and correlated with differences in the fine and course grain dislocation substructures. A mixtures model has been developed for the single crystal behavior that includes explicit dislocation substructure models. This model also incorporates reverse magnetostriction, which is a ferromagnetic phenomenon. Finiite element models have been developed using the mixtures models that simulate the formation and propagation of persistent slip bands, a type of shear band localization associated with a distinct dislocation substructure.
This project is aimed at achieving a fundamental understanding of low plastic strain amplitude cyclic deformation and fatigue behavior in ultra fine grain FCC metals that have a low initial dislocation density. Ultra fine grain metals are those that have grain diameters in the submicron range, but generally greater than about 10 nm. Ultra fine grain metals have been shown to exhibit exceptional strength with, in many cases, reasonable ductility. They are generally produced in one of three ways: by inert gas condensation and powder metallurgy, by severe plastic deformation of conventional grain size materials, and by electrodeposition. Materials produced by severe plastic deformation can exhibit both high strength and good ductility, but they have a very high dislocation density. Materials produced by inert gas condensation and powder metallurgy generally exhibit poor ductility. Only materials produced by electrodeposition have both low dislocation density and exhibit both high strength and good ductility. Thus, they offer potential for achieving good fatigue life characteristics relative to conventional grain size materials and ultra fine grain materials produced by other means.
Research Experience for Undergraduates: Nanoscale Science and Engineering for Materials Systems and Materials Processing. This program is designed to focus undergraduate research on an area identified as a national priority, thus providing an excellent platform for promoting graduate school among participating students. Undergraduate students participate in a ten week summer program with projects that focus either on materials processing/materials systems issues where alteration/exploitation of structure at the nanoscale is critical for achieving technological advances.
N.R. Batane, D.J. Morrison, and J.C. Moosbrugger, “Cyclic Plasticity of Polycrystalline Nickel under Axial-Torsional Loading,” Materials Science and Engineering A, 528, 467-473, doi:10.1016/j.msea.2010.09.039, 2010.
J.G. Kirk, S. Naik, D. Volkov, J.C. Moosbrugger, D.J. Morrison, and I. Sokolov, “Self-healing Epoxy Composites Based on the use of Nanoporous Silica Capsules,” International Journal of Fracture, 159, 101-102, DOI 10.1007/s10704-009-9375-y, 2009.
D. Zhou, J.C. Moosbrugger and D.J. Morrison, “A Substructure Mixtures Model for the Cyclic Plasticity of Single Slip Oriented Nickel Single Crystal at Low Plastic Strain Amplitudes,” accepted for publication in International Journal of Plasticity (January, 2005).
D.J. Morrison, Y. Jia and J.C. Moosbrugger, “Cyclic Plasticity of Nickel at Low Plastic Strain Amplitude: Constricted Hysteresis Loops,” Scripta Materialia, 44, pp. 449-453 (2001).
D.J. Morrison, Y. Jia and J.C. Moosbrugger, “Cyclic Plasticity of Nickel at Low Plastic Strain Amplitude: Hysteresis Loop Shape Analysis,” Materials Science and Engineering A,314, pp. 24-30 (2001).
J.C. Moosbrugger, D.J. Morrison and Y. Jia, “Nonlinear Kinematic Hardening Rule Parameters-Relationship to Substructure Evolution in Polycrystalline Nickel,” International Journal of Plasticity, 16, pp.439-467 (2000).
J.C. Moosbrugger, "Continuum Slip Viscoplasticity with the Haasen Constitutive Model: Application to CdTe Single Crystal Inelasticity,” International Journal of Plasticity, 11, pp. 799-826 (1995).
J.C. Moosbrugger and D.J. Morrison, “Nonlinear Kinematic Hardening Rule Parameters – Direct Determination from Completely Reversed Proportional Cycling,” International Journal of Plasticity, 13, pp. 633-668 (1997).
T.E. Stevens, J.C. Moosbrugger and F.M. Carlson, “Creep of CdZnTe at High Homologous Temperatures,” Journal of Materials Research, 14, pp. 3864-3869 (1999).
J.C. Moosbrugger, “Experimental Parameter Estimation for Nonproportional Cyclic Viscoplasticity: Nonlinear Kinematic Hardening Rules for Two Waspaloy Microstructures at 650 o C,” International Journal of Plasticity, 9, pp. 345-373 (1993).
J.C. Moosbrugger, “Nonisothermal Constitutive Model for the Small Strain Behavior of 9Cr-1Mo-V-Nb Pressure Vessel Steel,” ASME Journal of Engineering Materials and Technology , 114, pp. 354-361 (1992).
J.C. Moosbrugger, “Some Developments in the Characterization of Material Hardening and Rate Sensitivity for Cyclic Viscoplasticity Models,” International Journal of Plasticity, 7, pp. 405-431 (1991).