Local Stress and Damage Response of Polycrystal Materials to Light Shock. . .
215
Fig. 10 Density estimates of vonMises stress at all computational points in the 10 statistical
volume element polycrystal simulations at the conclusion of the loading profile given in Fig. 5
The experimental results shown earlier suggest that grain boundaries can provide
the conditions to enable pore formation for lightly loaded shock conditions.
Certainly, there is much which we do not yet understand about grain boundaries
which leads to grain boundaries being critical defects in some high purity materials.
The results given in Figs. 11, 12, 13, and 14 demonstrate high stress conditions at
some points on grain boundaries computed for the 10 statistical volume elements
used in this study. The results given in Figs. 15 and 16 feature the normal and shear
components of traction stresses on all grain boundaries within the 10 polycrystal
calculations as a function of angle of inclination of the grain boundary segment
relative to the shock direction. In both figures, angles of 0 and 180 are the points on
the curves where the grain boundary normal is parallel to the direction of shock. The
results in Fig. 15 show that the normal traction on grain boundaries perpendicular
to the shock direction display a high-tensile traction loading. Since the loading for
the shock conditions is overall hydrostatic, the results demonstrate that the normal
traction is tensile on all grain boundary surfaces. The shear traction component
215
Fig. 10 Density estimates of vonMises stress at all computational points in the 10 statistical
volume element polycrystal simulations at the conclusion of the loading profile given in Fig. 5
The experimental results shown earlier suggest that grain boundaries can provide
the conditions to enable pore formation for lightly loaded shock conditions.
Certainly, there is much which we do not yet understand about grain boundaries
which leads to grain boundaries being critical defects in some high purity materials.
The results given in Figs. 11, 12, 13, and 14 demonstrate high stress conditions at
some points on grain boundaries computed for the 10 statistical volume elements
used in this study. The results given in Figs. 15 and 16 feature the normal and shear
components of traction stresses on all grain boundaries within the 10 polycrystal
calculations as a function of angle of inclination of the grain boundary segment
relative to the shock direction. In both figures, angles of 0 and 180 are the points on
the curves where the grain boundary normal is parallel to the direction of shock. The
results in Fig. 15 show that the normal traction on grain boundaries perpendicular
to the shock direction display a high-tensile traction loading. Since the loading for
the shock conditions is overall hydrostatic, the results demonstrate that the normal
traction is tensile on all grain boundary surfaces. The shear traction component