Numerical modelling of the fracture toughness of structural steel

This paper presents investigations on the numerical simulation of the toughness of structural steel S355 J2 G3. The simulations for the upper and lower shelf are carried out using a material model according to Johnson and Cook which is available in a publicly available numerical simulation tool. It is evaluated if a conventional material model according to Johnson and Cook leads to sufficient results or if modified variants of the Johnson-Cook-model need to be considered. For this purpose, experimental data from different published test series are used and evaluated. Parameters for the material model are determined from the test data. It is observed, that the modified material model according to Johnson and Cook leads to more accurate results by including the fracture strain from real tests. By using commonly available software tools, published test data to benchmark the material model, tensile test results can be precisely simulated. Furthermore, it is observed that the solidification behaviour can be sufficiently determined with the benchmarked material model. Finally, it can be shown, that it is possible to numerically reproduce the material behaviour of structural steel using a commercially available FE program with a predefined closed material model at different temperature levels and loading speeds. By this, the actual load-bearing and fatigue behaviour of load-bearing structures can be estimated roughly.