13th International Conference on Fracture June 16–21, 2013, Beijing, China -6- why the normal and shear stress fields are computed for different values of SBα and GBα . The GB normal stress reaches a maximum peak for SBα equal to 45 o because of the corresponding highest Schmid factor value (f = 0.5). For lower or higher SBα values, the normal stress is lower (Fig. 5 a)) and the same almost occurs to the shear stress (Fig. 5 b)). Indeed, a lower Schmid factor leads to delayed plastic flow and low plastic slip which induces the stress concentration. Figure 6. a) GB normal stress b) GB shear stress, with respect to the distance to the GB-SB intersection in close field configuration for: Austenitic stainless steel, L=10.71 μm, t=0.09 μm, Σ0 = 878 MPa, αSB = 45°, τ0 = 60 MPa Concerning the GB orientation, the results show that GB stress fields slightly decrease with respect to GBα (see Fig. 6 a) and b)). 3.3. Influence of elasticity parameters One now aims to evaluate the influence of isotropic elasticity parameters. Fig. 7 a) and b) show GB stress fields computed for different materials, E1 =68GPa (Aluminum), E2 =110 GPa (Copper), E3 = 180 GPa (Austenitic stainless steel), and corresponding Poisson ratios, ν1 = 0.33 (Aluminum), ν2 = 0.343 (Copper), ν3 = 0.33 (Austenitic stainless steel) [29] . a) b) Figure 7. a) GB normal stress b) GB shear stress, with respect to the distance to the GB-SB intersection in close field configuration for: L=10.71 μm, t=0.09 μm, Σ0 = 393 MPa, αGB = 33°, αSB = 45°, τ0 = 60 MPa No difference with respect to these parameters is evidenced in the graphs. It has been checked that GB stresses are the same whatever the isotropic elastic parameters provided the remote tensile stress 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01 0 1000 2000 3000 4000 5000 6000 7000 8000 r [micron] GB normal stress [MPa] α GB =33 o α GB =40 o α GB =45 o 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01 0 1000 2000 3000 4000 5000 6000 7000 8000 r [micron] GB shear stress [MPa] α GB =33 o α GB =40 o α GB =45 o a) b) 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01 0 1000 2000 3000 4000 5000 6000 r [micron] GB normal stress [MPa] Aluminum Copper Austenitic stainless steel 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01 0 500 1000 1500 2000 2500 3000 r [micron] GB shear stress [MPa] Aluminum Copper Austenitic stainless steel
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