Issue 17

M. Paggi et alii, Frattura ed Integrità Strutturale, 17 (2011) 5-14; DOI: 10.3221/IGF-ESIS.17.01 9 Figure 5 : Material microstructure of polycrystalline Copper numerically analyzed in this work. (a) (b) Figure 6 : (a) Grain size distribution and (b) interface thickness distribution of the microstructure shown in Fig. 5. According to the thickness-dependent nonlocal CZM summarized in the previous section, the distribution of the Mode I interface fracture energy, represented by the area below the Mode I traction-separation curve, is obtained and shown in Fig. 7. It is interesting to note that the distribution of Mode I interface fracture energies for the present case (dots in Fig. 7) is better approximated by a Gaussian than by a Weibull distribution (see the probability plots in Fig. 7(a) and 7(b), where the Gaussian and Weibull distributions computed from the sample population are depicted with dashed-dotted lines). This is in general agreement with ductility of the material microstructure herein examined. Incidentally, we note that the Weibull modulus for these data is equal to 7.7, which is in agreement with the typical range of variation between 5 and 10 found in polycrystals [16]. This can be considered as an indirect experimental confirmation of the fact that the interface thickness distribution is responsible for the interface fracture energy distribution. (a) Gaussian probability plot (b) Weibull probability plot Figure 7 : Mode I interface fracture energy distribution and comparison with the Gaussian and the Weibull distributions.  1 μm d m