This paper modelled the cutting process of a bundle consisted of ultra-thin cold-rolled steel sheets using a guillotine. The geometry of a cutting tool with given dimensions was assumed. A bundle of sheets being cut was modelled as deformable, the cutting tool was rigid, and the finite element method along with computer system LS-DYNA was employed. Numerical simulations of the complex state of stress and of the corresponding complex state of strain were carried out. Cutting processes belong to fast changing physical phenomena, and therefore, highly nonlinear dynamical algorithms were applied in order to solve this particular problem. Experimental investigations were also conducted by means of the scanning electron microscopy. It was found that the fracture region consisted of two distinct zones: brittle and ductile separated from each other by the interfacial transition. Morphological features of the brittle, ductile, and the transition regions were identified. The ductile and brittle zones were separated at the depth of ca. 1/5 thickness of the cut steel sheet. Finally, the numerical results obtained by usage of the finite element method as well as experimental ones in the form of microscopic images were compared, showing quite good agreement.
Keywords: bundle of metal sheets; finite element method; metal fracture; nonlinear analysis; plastic and brittle cracking; plastic-brittle transition; scanning electron microscopy; ultra-thin steel sheet.