The mixed mode SIFs were calculated at those points shown in the Figs.
(6-10, 6-11, 6-12 on page 69) for all the three specimens on the mid plane of the
Brazilian disk specimens, assuming plane strain assumption. AKrms was calculated
using the following equation in order to compare with AKss.
AKrms = AKj + AK}, + AK}JJ
(6.15)
K..s was calculated using the equation (6.10), where state of stress obtained
from equation (6.11) was multiplied by Schmid's factor for FCC single i i,-l I as
defined in equation (1.13) to get the resolved shear stress intensity on all the 12
primary slip systems. The trace of the two slip planes (111) and (111) were found
to be making equal angles with the (111) plane (67.780), while the trace of the
plane (111) was making 00 with the crack plane (111) as shown in the Fig. 6-13.
(111) {1To0}
Plane along depth {1 1 2}
Trace of Slip Planes 11) Trace
SC Trace Plane
y 0 (Plane normal to
0= 670 Crack Plane)
0 = -670
z Trace of Slip Planes
Crack Surface ( 1 1)
Figure 6-13: Trace of primary slip planes on the plane normal to the crack plane
The load ratio R (min load/max load) was 0.1 (Table 6-1 on page 68), as the
load on the BD specimen alv-,x compressive. As SIFs are linearly proportional to
the load applied, therefore Krs. was multiplied with R to get the AKrss.