Modeling single-crystal microstructure evolution due to shock loading

18th APS-SCCM; 24th AIRAPT

Lloyd, J.T.^1 ; Clayton, J.D.^2 ; Austin, R.A.^3 ; McDowell, D.L.^1,4

Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta

GA, United States^1

Impact Physics Branch, US Army Research Laboratory, Aberdeen Proving Ground

MD, United States^2

Materials Modeling and Simulation Group, Lawrence Livermore National Laboratory, Livermore

CA, United States^3

School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta

GA, United States^4

关键词: Artificial viscosity;    Dislocation density evolution;    Elastic-plastic Material;    Elastic-plastic response;    Macroscopic velocity;    Material orientation;    Micro-structure evolutions;    Numerical implementation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/500/11/112040/pdf
DOI  :  10.1088/1742-6596/500/11/112040

来源: IOP

【 摘 要 】

An existing high strain rate viscoplastic (HSRVP) model is extended to address single-crystal anisotropic, elastic-plastic material response and is implemented into a steady plastic wave formulation in the weak shock regime. The single-crystal HSRVP model tracks the nucleation, multiplication, annihilation, and trapping of dislocations, as well as thermally activated and phonon drag limited glide kinetics. The steady plastic wave formulation is used to model the elastic-plastic response with respect to a propagating longitudinal wave, and assumes that the magnitudes of quasi-transverse waves are negligible. This steady wave analysis does not require specification of artificial viscosity, which can give rise to spurious dissipative effects. The constitutive model and its numerical implementation are applied to single-crystal pure Al and results are compared with existing experimental data. Dislocation density evolution, lattice reorientation, and macroscopic velocity-time histories are tracked for different initial orientations subjected to varying peak shock pressures. Results suggest that initial material orientation can significantly influence microstructure evolution, which can be captured using the modified Taylor factor.