J. Flodr et alii, Frattura ed Integrità Strutturale, 39 (2017) 62-71; DOI: 10.3221/IGF-ESIS.39.08 65 Fine mesh size - 0.75 mm Typical mesh size - 1.5 mm Figure 4 : Numerical model of a sample with typical mesh. Figure 5 : Material diagram of steel. Maximal von Mises stress in deformed model is shown in the Fig. 6. This case is for critical force. Concentration of stress in numerical model corresponds with real deformation of sample, see Fig. 2.