PSI - Issue 42

Lucas Mangas Araújo et al. / Procedia Structural Integrity 42 (2022) 1591–1599 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Table 1. Material parameters calibrated for the SAE 1045 in Monotonic and ULCF conditions, Bai [1].

3.2. Monotonic results. A simulation with = = 0 (recovering von Mises) is conducted to evaluate the influence of 3 on the Ductile Fracture behavior of SAE 1045 steel. The result of this simulation enables to estimate a range of possible values. Based on works in the literature [3, 12, 13] and on the predicted von Mises numerical response, one tests different within the interval [−100.0, −10.0] . The lower bound of this range was chosen due convexity issues related with high negative values (see [12]). The best trade-off relation (with respect to computational time and convergence) was achieved with = −60.0 . When larger (in absolute value) were tested, convergence issues were observed, possibly related to convexity loss. This latter implies on non-positive dissipation, which is reflected on the convergence problems of the numerical solution. On the left of Fig.3, the numerical reaction curves obtained with = = 0 and = 0 (red star-dashed line), = −60.0 (blue square-dashed line) are displayed and compared with the experimental data.

Fig. 3. Comparison between the numerical responses of Mises and Gao based formulations with the experimental reaction curve for the horizontal tension test (+0◦ loading direction). On the left, only is activated, while on the left both and are considered.