Prediction of fracture toughness in ductile-to-brittle transition region using combined CDM and Beremin models

The effect of subcritical ductile crack growth on cleavage fracture probability in the transition regime using continuum damage mechanics simulation

“…What characterize the proposed modeling approach with respect to similar attempts proposed in the literature is that the use of BDM allows to predict with high accuracy the effective ductile crack growth occurring in cracked geometry with different constraint without the need to adjust or recalibrate material parameters. With this modeling, the scatter band occurring in the fracture toughness values for different specimen geometry could be predicted with a very good agreement with master curve prediction (error at 95% of failure probability less than 10%) [21]. Numerical simulation provided a prediction of the amount of ductile crack growth occurring prior to cleavage.…”

“…The authors found the following physically-based relationship for the dependence of this parameter with temperature as discussed in [21],…”

“…Predicted behavior was compared with experimental data, coming from different sources [40,47], and with the master curve [48]. A detailed discussion can be found elsewhere [21]. In Figs.…”

“…Here, the modified Beremin model (MBM) [19] for cleavage fracture and the Bonora damage model (BDM) [20] for ductile rupture have been combined and used for this purpose. In the following, the combined model, which was previously used to predict specimen geometry effect on the master curve reference temperature T 0 [21], is briefly reviewed. Successively, results of a detailed computational analysis of compact tension (CT) and single edge notch in bending (SEB) specimen geometry, with different crack depth ratios, in the upper shelf region (T 0 + 50°C) -where stable crack growth prior to cleavage fracture becomes relevant-are presented and discussed.…”

Statistical assessment of notch toughness against cleavage fracture of ferritic steels

“…The Beremin model has suffered from the ambiguity in model parameter calibration, ie, the variation of the model parameters with temperature and geometrical constraint. Many empirical modifications to the Beremin model have been proposed by either introducing a fixed‐value threshold stress (σ th ), eg, in the literature, or incorporating the plastic strain (ε p ) effect, eg, in Ruggieri et al As a result, different expressions of the Weibull stress σ W have been proposed to calculate the cumulative probability based on Equation . Here are 2 examples that used a fixed‐vale threshold stress σ th for modifications: Bakker and Koers redefined the Weibull stress σ W in Equation as …”