5. Alternative approaches

Among the local models introduced in code_aster ([R7.02.06] and [U2.05.08]) that make it possible to describe fragile breakage by cleavage, there is the Bordet model (see [16] and []). R7.02.06 This model represents an extension of the Beremin model where it is assumed that the microcracks created when the plasticity threshold is reached remain potentially active throughout the subsequent loading. However, in steels, the overall failure is mainly linked to newly created microcracks. It is therefore necessary to take into account the level of plastic deformation reached at each moment. This option is possible in the Beremin model via the plastic correction option described in paragraph § 3.4. The effect of plasticity on microdefects is taken into account in the Bordet model by considering that the probability of cleavage is expressed as the product of the probability of nucleation and propagation at the same time.

Among other alternative approaches, there is the Gp approach, which makes it possible to define a criterion for initiating an already existing crack through the calculation of elastic energy recovery rates. This approach is valid for linear elasticity as well as for non-linear elasticity.

The Gp model is a deterministic energy approach. This approach is currently internal to EDF; it does not have the maturity of Beremin’s approach, but it nevertheless has the advantage of being similar, in its use, to the J-approach, which also makes it a credible candidate for use in engineering files [29]. For more details on this approach, we can refer to [R7.02.16].