2183 KB33 KB199920252014Halilovič, MiroslavStarman, BojanŠtok, BorisVrh, Markoštevilka:2letnik:60str. 84-92, SI 21ISSN:0039-2480COBISSID:13345307URN:URN:NBN:SI:doc-AW67Y117enZveza strojnih inženirjev in tehnikov Slovenije et al.Strojniški vestnikdegradacija togostielastična povračljivostelastične lastnostiplastična anizotropijapoškodovanostAdvanced modelling of sheet metal forming considering anisotropy and youngs modulus evolution|The paper focuses on the modelling of springback within a formed stainless steel sheet. The main subject of this work is the construction of aconstitutive model which simultaneously considers sheet anisotropy, damage evolution, and stiffness degradation in material during forming.The developed model is based on the Gurson-Tvergaard-Needleman damage model, which is adequately extended by the implementationof the anisotropic Hill48 plasticity and MoriTanakas approach to stiffness degradation. Considering the established relationships, somematerial parameters that are included in the model are characterised by the corresponding measurements. The experimental validation ofthe developed constitutive model is performed on a springback test, which consists of bending and releasing rectangular stainless steelspecimens that were previously plastically prestrained to a different degree, either in the rolling or transverse direction. A comparison ofthe proposed modelling approach to the classical approach by using the Hill48 model clearly indicates that the simultaneous modelling ofmaterial phenomena, especially the coupling of stiffness degradation with anisotropic plasticity, can be the true key to obtaining a moreaccurate prediction of the springback in sheet-metal-forming applicationsČlanek obravnava konstitutivno in numerično modeliranje procesa preoblikovanja nerjavne pločevine s poudarkom na napovedi elastične povračljivosti. Znano je, da se med obremenjevanjem v pločevini poleg trajne deformacije razvija tudi poškodovanost v obliki mikropraznin, votlinic in razpok. Pojav je razpoznaven z opazovanjem mikrostrukture pločevine, ki je bila predhodno obremenjena do določene stopnje trajne deformacije. Glede na teorijo mehanike poškodb so tako nastale praznine in mikro razpoke glavni vzrok za degradacijo togosti v duktilnih materialih, kar ima nadalje pomembno vlogo pri napovedovanju elastične povračljivosti. Ker je pločevina zaradi procesa izdelave anizotropna, ima tudi to pri napovedovanju pomemben vplivTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo