A simplified use of Gp 2D approach
by R. Bargellini, EDF R&D / AMA
The Gp approach of fracture mechanics enables the prediction of the initiation of a cleavage default. This deterministic approach is valid for an elastoplastic framework, even when unloading occurs. It has been developed at EDF R&D for the past fifteen years and accounts for the effects of small defects and warm pre-stressing.
A barrier to the wide-spread use of this approach is the need for a particular mesh, where the fault is represented by a notch, in front of which particular zones, called shavings, are defined.
The new CALC_GP and RAFF_GP commands allow to overcome the definition of these shavings. The user can now provide any mesh, in which the defect is still represented by a notch (sufficiently refined).
Before the mechanical calculation, the mesh may be refined in the area of interest (downstream of the notch tip) with the new RAFF_GP command. The figure below presents a mesh before and after the refinement.
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The calculation of the Gp parameter is done in post-processing of the mechanical computation through the CALC_GP command, which accepts any 2D mesh (3D meshes must still contain the predefined shavings). The zones are then reconstructed by groups of Gauss points, as shown in figure 2.
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Available in 11.3.7 and later versions for CALC_GP and in 12.0.15 and later versions for RAFF_GP.