In the last decade, the favorable properties of the press hardening process for advanced high strength steel (AHSS) have increased the demands concerning passenger safety and lightweight design. AHSS show excellent mechanical properties from e.g. tensile test measurements, but it has previously been shown that results from tensile elongation or energy calculation of un-notched and smooth specimen are not appropriate to classify the crash behavior of steel grades. This is because they completely underestimate the post-uniform region from start of necking to failure. Another issue, the mechanical behavior of a notched or cracked component is different than a smooth and un-notched component. If the mechanical behavior in some loading is dominated by crack propagation, it should be rationalized in terms of the materials crack propagation resistance. Therefore, the evolution of the material property that controls crack propagation, i.e. the fracture toughness, is an interesting approach to evaluate loading and deformation of AHSS. Process modelling including fracture toughness depending properties gives valuable information and addi-tional understanding of fracture behavior and crack propagation mechanisms in AHSS compo-nents. Fracture toughness in thin sheets can be readily measured through the application of the Essential Work of Fracture (EWF) methodology. The damage evolution law can be specified in terms of fracture energy (per unit area) or in terms of equivalent plastic failure strain as a function of triaxiality and lode angle. In this work, DENT test samples have been experimentally evaluated and finite element simulations of the DENT tests have been performed. By this approach the numerical study includes mechanical response of AHSS specimen including sharp cracks. In the numerical model, the J-integral was evaluated using the virtual crack-tip extension (VCE) method. From the comparison of the numerical and experimental results of load-displacement for differ-ent ligament length cases it is obvious that there are in agreement. Also, the numerically obtained value of fracture toughness Jc, is in agreement with the experimentally measured value of essen-tial work of fracture we. When finite element based fracture mechanics is applied to practical design, the fracture tough-ness can be used as design criteria. One appealing property of the evaluation of the J-integral is that it can be evaluated from the far field solution, which facilitates computation as many numer-ical errors arise close to the crack tip. Evolution of stress- and strain field, plastic zone, J-integral value and other mechanical properties is interesting to study with the combination of experi-mental and numerical investigations.
