An integrated approach to model strain localization bands in magnesium alloys
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Strain localization bands (SLBs) that appear at early stages of deformation of magnesium alloys have been recently associated with heterogeneous activation of deformation twinning. Experimental evidence has demonstrated that such “Lüders-type” band formations dominate the overall mechanical behavior of these alloys resulting in sigmoidal type stress–strain curves with a distinct plateau followed by pronounced anisotropic hardening. To evaluate the role of SLB formation on the local and global mechanical behavior of magnesium alloys, an integrated experimental/computational approach is presented. The computational part is developed based on custom subroutines implemented in a finite element method that combine a plasticity model with a stiffness degradation approach. Specific inputs from the characterization and testing measurements to the computational approach are discussed while the numerical results are validated against such available experimental information, confirming the existence of load drops and the intensification of strain accumulation at the time of SLB initiation.
KeywordsStrain localization Magnesium alloys Twinning Digital image correlation Finite element method
The corresponding author acknowledges the financial support provided by the National Science Foundation through the CMMI #1434506 award to Drexel University. He also acknowledges the technical support received under the National Aeronautics and Space Administration Space Act Agreement, No. SAA1-19439 with Langley Research Center. The results reported were obtained by using computational resources supported by Drexel’s University Research Computing Facility. This investigation was also supported by the funds received in terms of fellowship to M. Cabal from the Greater Philadelphia Region Louis Strokes Alliance for Minority Participation.
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