Local Stress and Damage Response of Polycrystal Materials to Light Shock. . .
219
6 Conclusion
The microstructure of polycrystalline metallic materials is known to affect the
nature of porosity-based damage initiation and growth for shock loading conditions. Experimental results have suggested that for high-purity materials, such as
the tantalum of interest here, grain boundaries are prominent locations for pore
nucleation. The polycrystal calculations performed for this study have provided
insight into the stress conditions within the microstructure and the conditions at
the grain boundaries. Each of the polycrystal realizations are soft-coupled to the
macroscale model via the computed stress conditions predicted for a tantalum on
tantalum plate impact experiment. The computational results presented can provide
information which is supplemental to those derived by experiment due to the
diagnostic limitation of current experimental capability. This information can then
in turn be used to further advance our macroscale ductile damage models to improve
both physical and computational performance for component scale simulations.
Acknowledgments This work was performed at Los Alamos National Laboratory and funded
through the Laboratory Directed Research and Development program via projects 20170033DR
and 20150594ER. The authors also wish to acknowledge the assistance provided by Dr. M.
Ardeljan in constructing the SVEs used in this study.
References
1. F.L. Addessio, J.N. Johnson, Rate-dependent ductile failure model. J. Appl. Phys. 74, 1640–
1648 (1993)
2. C. Alleman, S. Ghosh, D.J. Luscher, C.A. Bronkhorst, Evaluating the effects of loading
parameters on single crystal slip in tantalum using molecular mechanics. Phil. Mag. 94, 92–116
(2013)
3. C. Alleman, D.J. Luscher, C.A. Bronkhorst, S. Ghosh, Distributed-enhanced homogenization
framework and model for heterogeneous elasto-plastic problems. J. Mech. Phys. Solids 85,
176–202 (2015)
4. L. Anand, Single-crystal elasto-viscoplasticity: application to texture evolution in polycrystalline metals at large strains. Comput. Methods Appl. Mech. Eng. 193, 5359–5383 (2004)
5. R.J. Asaro, J.R. Rice, Strain localization in ductile single crystals. J. Mech. Phys. Solids 25,
309–338 (1977)
6. A. Acharya, A.J. Beaudoin, Grain size effect in viscoplastic polycrystal at moderate strains. J.
Mech. Phys. Solids 48, 2213–2230 (2000)
7. R. Becker, Ring fragmentation predictions using the Gurson model with material stability
conditions as failure criteria. Int. J. Sol. Struct. 39, 3555–3580 (2002)
8. R. Becker, Effects of crystal plasticity on materials loaded at high pressures and strain rates.
Int. J. Plasticity 20, 1983–2006 (2004)
9. C.A. Bronkhorst, S.R. Kalidindi, L. Anand, Polycrystal plasticity and the evolution of
crystallographic texture in FCC metals. Phil. Trans. R. Soc. Lond. A 341, 443–477 (1992)
10. C.A. Bronkhorst, G.T. Gray III, F.L. Addessio, V. Livescu, N.K. Bourne, S.A. MacDonald,
P.J. Withers, Response and representation of ductile damage under varying shock loading
conditions in tantalum. J. Appl. Phys. 119, 085103 (2016)
219
6 Conclusion
The microstructure of polycrystalline metallic materials is known to affect the
nature of porosity-based damage initiation and growth for shock loading conditions. Experimental results have suggested that for high-purity materials, such as
the tantalum of interest here, grain boundaries are prominent locations for pore
nucleation. The polycrystal calculations performed for this study have provided
insight into the stress conditions within the microstructure and the conditions at
the grain boundaries. Each of the polycrystal realizations are soft-coupled to the
macroscale model via the computed stress conditions predicted for a tantalum on
tantalum plate impact experiment. The computational results presented can provide
information which is supplemental to those derived by experiment due to the
diagnostic limitation of current experimental capability. This information can then
in turn be used to further advance our macroscale ductile damage models to improve
both physical and computational performance for component scale simulations.
Acknowledgments This work was performed at Los Alamos National Laboratory and funded
through the Laboratory Directed Research and Development program via projects 20170033DR
and 20150594ER. The authors also wish to acknowledge the assistance provided by Dr. M.
Ardeljan in constructing the SVEs used in this study.
References
1. F.L. Addessio, J.N. Johnson, Rate-dependent ductile failure model. J. Appl. Phys. 74, 1640–
1648 (1993)
2. C. Alleman, S. Ghosh, D.J. Luscher, C.A. Bronkhorst, Evaluating the effects of loading
parameters on single crystal slip in tantalum using molecular mechanics. Phil. Mag. 94, 92–116
(2013)
3. C. Alleman, D.J. Luscher, C.A. Bronkhorst, S. Ghosh, Distributed-enhanced homogenization
framework and model for heterogeneous elasto-plastic problems. J. Mech. Phys. Solids 85,
176–202 (2015)
4. L. Anand, Single-crystal elasto-viscoplasticity: application to texture evolution in polycrystalline metals at large strains. Comput. Methods Appl. Mech. Eng. 193, 5359–5383 (2004)
5. R.J. Asaro, J.R. Rice, Strain localization in ductile single crystals. J. Mech. Phys. Solids 25,
309–338 (1977)
6. A. Acharya, A.J. Beaudoin, Grain size effect in viscoplastic polycrystal at moderate strains. J.
Mech. Phys. Solids 48, 2213–2230 (2000)
7. R. Becker, Ring fragmentation predictions using the Gurson model with material stability
conditions as failure criteria. Int. J. Sol. Struct. 39, 3555–3580 (2002)
8. R. Becker, Effects of crystal plasticity on materials loaded at high pressures and strain rates.
Int. J. Plasticity 20, 1983–2006 (2004)
9. C.A. Bronkhorst, S.R. Kalidindi, L. Anand, Polycrystal plasticity and the evolution of
crystallographic texture in FCC metals. Phil. Trans. R. Soc. Lond. A 341, 443–477 (1992)
10. C.A. Bronkhorst, G.T. Gray III, F.L. Addessio, V. Livescu, N.K. Bourne, S.A. MacDonald,
P.J. Withers, Response and representation of ductile damage under varying shock loading
conditions in tantalum. J. Appl. Phys. 119, 085103 (2016)