• elementi finiti
• meccanica della frattura
• stress intensity factor
• weight function

In the study of the cracks located in a Reactor Pressure Vessel, the weight functions method is a quick method because allows to calculate the SIF conveniently for a given geometry and dimension of the cracks without to develop the cracks in the structural analysis. In the last century many weight functions have been developed. The application of these functions has been showed different results. For this reason a parametric finite element model have been modelled for the analyses with Ansys. The first step of our work has been the verification of the finite element model, with exact solution of the stress intensity factor for embedded circular and with approximated solution for elliptical cracks in an infinite body.
The model is building in a parametric manner to be used for any dimension of the crack.
If we consider an elliptical crack with aspect ratio of a/c with the width of the plate w, the only parameters that we change are c and w. For the circular crack in an infinite body the value for the parameter w are w/a¡Ý 8 and w/c¡Ý8 (see fig. 1).
These results for the embedded elliptical and semi-elliptical have been indicated that the finite element models are suitable for the analyses of the elliptical cracks with aspect ratios in the range 0 ¡Ü a/c ¡Ü 1 and relative depths 0 ¡Ü a/w ¡Ü 0.8. The second step has been executed the verify of the weight functions with the finite element results for the constant and linear stress fields and good agreement was achieved.