4. Features and validation#

4.1. Tips for using settings#

In summary, for the search for the crack path the necessary parameters are:

  • \({l}_{\mathrm{orth}}\) (LONG_ORTH)

  • \({l}_{\mathrm{reg}}\) (LONG_REG)

  • \(a\) (PAS)

  • \({N}_{\mathit{orth}}\) (NB_POINT)

  • BORNE_MIN

to be entered under the keyword factor RECHERCHE. The recommended range of use is as follows:

  • \({l}_{\mathit{orth}}\) must be greater than or equal to the width of the damaged band; good results are already obtained by adopting twice this width;

  • \({l}_{\mathrm{reg}}\) may be in the interval \(0.5\Delta \le {l}_{\mathit{reg}}\le 2\Delta\), \(\Delta\) being the size of the finite elements in the damaged areas (compromise between sufficient smoothing and the risk of losing too much information from the unsmoothed damage profile);

  • \(a\) depends on the curvature of the path and how many points the user wants to describe the crack, as an indication it can also be taken in an interval \(0.5\Delta \le a\le 2\Delta\);

  • the choice of \({N}_{\mathrm{orth}}\) must guarantee at least 10 points per finite element;

  • BORNE_MIN is the value of the field for which the search is stopped in one direction; in the case of damage, values \(>0.5\) are taken to be sure that the crack is well formed.

For the calculation of the crack opening, the parameter BORNE_MAX must be less than 0.8, if field \(X\) is the damage.

4.2. Validation#

The order is validated by the zzzz264 test case [V1.01.264].

In modeling A, a crack path is sought and compared with an analytical path.

In B, C modeling, we look for the crack path and the opening on a mechanical result, obtained using Code_Aster damage laws.