| Resumo : |
A device apparatus was designed and built to enable testing of sheet metal undergoing to cyclic forward and reverse tension-compression loads, under plastic deformation, while preventing buckling of the specimen. This test allows the identification of parameters for the characterization of material according to advanced hardening models, which are of great interest to the automotive industry. Material simulation through more sophisticated models allows for a improved accuracy, hence, a better representation of the physical phenomena of mechanical forming, which enables tighter manufacturing tolerances. The test specimens were manufactured from steel sheets of the materials BH220 and DP600, with thicknesses of 0.65 mm and 1.0 mm, respectively. For each tested specimen, three tension-compression cycles were performed at a displacement rate of 0.5 mm/min. The maximum displacements were 0.6 mm in tension and 0.6 mm in compression. A fork configuration was used, in which the device has four main plate blocks to transmit the longitudinal displacement of the machine to the sheet metal and to restrict the out-of- plane transverse displacement. The test analysis indicates that the device can provide accurate results for high-resistance steels, with maximum deviation of 0.3%. |