An efficient way of reducing CO2 emissions from the transportation sector is to reduce the vehicle weights, i.e. lightweighting. A common strategy for lightweighting of vehicles is to replace the steels used to build structural parts of the vehicle, usually manufactured by metallic sheets, with stronger, advanced high strength steel (AHSS) grades. Using stronger steel grades enables down-gauging while the structural integrity of the parts remain unchanged. However, the increase in strength of AHSS typically comes with a loss of ductility, affecting their forming properties. A common AHSS manufacturing defect is edge cracking occurring when a sheared edge (damaged by the shearing operation) is bent or stretched. It is known in the sheet metal forming industry that the shear cutting process introduces damage, in terms of micro-cracks and notches, to sheared edges from which edge cracks can grow. Conventional forming analyses do not include the effects from sheared edge damage and therefore can not predict edge cracking during forming. Numerical modelling of the shear cutting process can aid the understanding of sheared edge damage and how it affects the AHSS edge cracking phenomena.

This thesis presents experimental and numerical methods for calibration of acommercial damage- and failure model, intended for shear cutting simulations. Crack initiation and propagation govern the shear cutting process of AHSS sheets. Therefore, a commercial numerical damage- and failure model was studied regarding its ability to predict shear edge damage. The investigation shows that the damage and failure model has limitations concerning prediction of crack initiation, thus concluding that modelling of processes including formation of cracks using the said damage- and failure model risks to generate erroneous results. This phenomena was also seen in modelling of shear cutting, where the crack-driven fracture process following burnish formation was delayed. Through sensitivity analysis of uncalibrated areas on the failure locus could accurate correlation between numerical and experimental cut edge morphology be obtained. Such results show that additional calibration experiments are necessary, but also the need for development of stress-state dependent failure modelling of AHSS that includes the effect from cracks.

Shear cutting is the primary method for preparing blanks in sheet metal forming, widely used across various sheet materials. However, when applied to advanced high-strength steels (AHSS), the process introduces additional challenges. While AHSS offer superior strength-to-weight performance, their limited ductility makes them highly sensitive to shear-induced edge damage, which can lead to premature edge cracking and reduced formability. Accurate numerical modelling of shear cutting and its effects is therefore essential for optimising manufacturing processes and improving formability predictions.

In this thesis, the Particle Finite Element Method (PFEM) was employed to develop a numerical framework for modelling of the shear cutting process, addressing challenges associated with extreme deformations and localised strain effects. PFEM provided a robust approach for modelling large localised deformations and material separation while preserving detailed information in critical regions along the cut edge. The method was validated against experimental sheet punching tests, demonstrating its ability to accurately capture key aspects of the shear cutting process. The developed PFEM model was further extended to examine the influence of cutting conditions on sheared edge formability, providing insights into how variations in cutting parameters affect edge cracking. A hybrid modelling approach was introduced, combining numerical shear cutting results with experimental observations to assess circumferential variations in cut edge morphology. This approach enabled a more detailed analysis of local heterogeneities in sheared edges, which are often overlooked in conventional numerical assessments. Additionally, a critical investigation of continuum-based ductile damage modelling for pre-cracked AHSS sheets highlighted the limitations of strain-driven failure models in capturing crack evolution. This study suggested that fracture mechanics approaches could provide a more reliable alternative for predicting crack propagation in edge cracking scenarios.

The findings of this thesis enhance the understanding of shear-induced damage mechanisms and their role in subsequent forming defects, providing valuable insights for minimising edge cracking in AHSS. The successful application of PFEM, combined with ductile damage and failure modelling, demonstrates its effectiveness as a robust and computationally efficient method for capturing extreme deformations and fracture evolution in shear cutting, contributing to the advancement of state-of-the-art shear cutting simulations. Moreover, the results highlights the significance of circumferential variations in sheared edge morphology, emphasising the need for precise cutting conditions and tool maintenance. These advancements contribute to the optimisation of shear cutting processes and broader applications of PFEM in large deformation solid mechanics, supporting the development of lightweight, high-performance AHSS structures.