The study of the different theories of brittle fracture mechanics shows that the tenacity of a material can be used as a maximum value of the stress intensity factor of the opening mode of a crack to determine the risk of brittle fracture of a thin piece of a structure submitted to a tensile load. Among the different practical methods of determination of the stress intensity factor which are presented: Iterative methods, finite element method (FEM), boundary integral equation methods (BIEM), the last one seems to be the most convenient in a general three dimensional case. Their different formulations are developed. For a three dimensional case, a comparison between FEM and BIEM shows that the second one leads to a simpler surface meshing with far less... |