A PFEM approach to model shear cutting of high strength steel sheets

  • Sandin, Olle (Luleå University of Technology)
  • Rodríguez Prieto, Juan Manuel (EAFIT University)
  • Hammarberg, Samuel (Luleå University of Technology)
  • Casellas, Daniel (Eurecat)

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The use of Advanced High Strength Steel (AHSS) allows for lightweighting of sheet steel components, with maintained structural integrity of the part. This has enabled a wide-spread use of the materials and an ever-increasing development of new, even stronger AHSS grades. However, with increased strength comes limited formability and unforeseen manufacturing defects. Edge-cracking is a manufacturing defect common in cold forming of AHSS, which arises from damage introduced to the cut edge during the shear cutting process, prior to the forming steps. The edge-cracking phenomena cannot be predicted using conventional forming limit diagram. Consequently, new predictive tools are required. Numerical modelling of the shear cutting process can aid the understanding of the sheared edge damage, thus avoiding unforeseen edge failure in subsequent cold forming. However, the extreme deformations and failure of the workpiece during the shear cutting process are likely to cause numerical instabilities and divergence using conventional Finite Element modelling. To overcome these challenges, this work uses the Particle Finite Element Method (PFEM) for numerical modelling of the shear cutting process. Even though PFEM was developed for incompressible flows [1], it provides accurate handling of some of the challenges encountered in modelling of shear cutting, such as large deformation, angular distortions, generation of new boundaries and efficiently minimising results diffusion during remeshing. The efficiency of PFEM in non-linear solid mechanics has in previous research also been proven suitable for orthogonal metal cutting with chip formation [2,3]. The present work shows prediction of the shear cutting process of AHSS using an axisymmetric PFEM modelling scheme with ductile damage implementation, where the numerical results are verified against experiments. With these results, the authors show new possibilities to obtain accurate numerical prediction of the shear cutting process, which promotes further advances in prediction of edge damage related to shear cutting of AHSS.