Issue 41

L. Patriarca et alii, Frattura ed Integrità Strutturale, 41 (2017) 277-284; DOI: 10.3221/IGF-ESIS.41.37 282 crack, which was not visible in Fig. 4. The secondary crack is emanating from the right side of the notch; its length is 40  m and its effect will be considered in the following models. Figure 5 : Residual strain field at crack tip measured by Digital Image Correlation. Q UASI - STATIC CRACK - FINITE ELEMENT ANALYSIS he characterization of the model shown in Fig. 6 required the adoption of some hypotheses: 1. The volume modeled by CP material is confined around the notch and reproduces the EBSD scan information; 2. The remaining volume of the specimen is modeled as purely elastic: its main purpose is to transfer the displacement field generated by the remote applied loading/boundary conditions to the CP portion of material. This hypothesis is acceptable since plastic deformations are confined around the notch; 3. The geometry of the grains in the thickness was considered columnar; 4. The primary crack first, and the secondary one later, were modeled as uniform through the thickness. Figure 6 : Model of the quasi-static crack experiment: definition of the loading condition and constraints. Focus on the area modeled by crystal plasticity. Fig. 6 shows loading and constraint configurations: the load was applied as a force to one node whose displacements were coupled to all nodes belonging to the loaded surface; the opposing face of the specimen was fully constrained in displacement. Finally, Fig. 6 focuses on the details of the CP area modeled and the mesh; here grains geometry and orientations derive from the EBSD. The model, in the CP volume, counts about 1230 grains; they were modeled by 235000 linear hexahedral elements, out of the 350000 of the whole model. T 