An efficient meshing approach for the calculation of notch stresses

For the application of the notch stress approach, local stresses at the notch root have to be calculated. This demands a fine discretization of the finite element model in the notch leading for complex structures to large finite element models which are difficult to handle and take a high amount of calculation time. This paper contains the detailed investigation of the required finite element mesh in the notch area for application of the notch stress approach. Based on small-scale specimens, various meshing rules are applied and compared to each other. As the most important factor for the efficiency of a finite element mesh, the element shape in the notch root was identified. It should be chosen according to the stress gradients: The higher the stress gradients are, the smaller the element edge length should be modeled. The shape of the subsequent elements inside the volume has no major influence on the accuracy of the calculation. Recommendations for practical use are given for various element types, including commonly used tetrahedron and hexahedron element with linear and quadratic shape function. Expected numerical errors for the chosen mesh configuration are indicated.