1. Introduction

The estimation of the opening of cracks is important in many industrial applications, for example the evaluation of permeability in structures that have the function of guaranteeing tightness.

The aim of POST_ENDO_FISS [U4.86.01] is to extract the crack opening from a calculation based on the mechanics of continuous media. The command is used as post-processing and therefore does not burden the calculation itself. The method used is able to find the crack path from the map of a field (scalar) \(X\) that represents the crack, and then determine the opening on the crack.

The evaluation of the crack opening is therefore divided into two steps: first the automatic search for the crack path, then the extraction of the opening. For now, the order applies to 2D studies.

If damage models or other softening laws of behavior are used for mechanical calculation, it is necessary for correct application of the command that regularization methods be used: this will make it possible to obtain fields that are well distributed over several finite elements. Also, the regularization methods will avoid any dependence of the results on the mesh.