PSI - Issue 42

António Mourão et al. / Procedia Structural Integrity 42 (2022) 1744–1751 António Mourão / Structural Integrity Procedia 00 (2019) 000 – 000

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Given that the analysis of the microstructural diagram shown in Fig. 2 portrays an isotropic grain distribution, an isotropic texture was also assumed in generated RVE model, i.e., the grain orientation were generated randomly, which can be visualized in Figure 4 where the pole figures for orientations <001> and <111> show no preferential crystallographic orientation of the RVE model. A set of Euler angles is used to specify the 3D orientation of each grain concerning the specimen axes.

Fig. 4. Pole figures of (a) <001>, (b) <111> orientation for the crystallographic orientations of the RVE model.

4. Results 4.1. Numerical results

Using the tensile monotonic tests conducted using Várzeas bridge material experimental data, it is possible to fit the material parameters used in the CPFE model, as shown in Table 1. As can be seen in Figure 5, this model neglects the yield stress level plateau, regardless, the model shows a good ability to represent the stress-strain monotonic curve of the case study. Additionally, obvious shear bands due to crystal slip can be observed in Figure 6. These local stress concentrations occur due to the non-uniformity of the material microstructure.

Table 1. Várzeas bridge material parameters of the CPFE model.

Slip system {110}<111>

Slip system {211}<111>

Material parameters

Elastic constants C 11 , MPa Elastic constants C 12 , MPa Elastic constants C 44 , MPa Reference strain rate ̇ , s -1 n Kinematic hardening, c 1 Kinematic hardening, c 2 Isotropic hardening, b Isotropic hardening, Q , MPa K , MPa

233000 135000 118000

233000 135000 118000

0.001

0.001

20 98 50

20

300 150

1.12

1 1

1

100

100