Limits to the ductility of metal sheets subjected to complex strain-paths

Experimental characterization and numerical prediction of ductile damage in forming of AA1050-O sheets

“…2b). Hydraulic bulge tests can give more informations about the nature of the material anisotropy and its dependence to the strain paths (Mesrar et al, 1998).…”

Intrinsic diagram of sheet metal forming limits for arbitrary strain paths

“…Assuming a given value of θ b , ψ b can be determined from equation ( 23) and ε b is derived from equation (24). As for the bulk, the principal strain-increment ε b 1 and ε b 2 are determined using equation (7), and the through-thickness strainincrement ε a 3 is determined from the condition of plastic incompressibility.…”

“…The assessment of material ductility has received a great deal of attention during the last thirty years [1][2][3][4][5][6][7][8][9][10]. For sheet metals under biaxial tension, the forming limit diagram (FLD) is currently employed as an indicator of ductility [11,12]. The FLD represents the plot of the value ε * 1 of the larger surface strain against the limit value ε * 2 of the smaller surface strain under proportional in-plane loading.…”

A crystal plasticity based estimate for forming limit diagrams from textural inhomogeneities

“…The onset of necking is often defined by the appearance of a much higher strain rate inside a shear band than outside. That definition is successfully exploited within the framework of the MK approach [5][6][7][8][9][10][11][12][13][14][15], where the location of a shear band is known. In the case of a material imperfection based method, the morphology of the localisation zone is unknown and therefore this straight-forward approach cannot be pursued.…”

“…The MK analysis was successfully used to predict the formability under monotonic deformation [5,6] and deformation with strain path changes [7][8][9]. Within the MK framework, the influence of various constitutive features on FLDs has been explored using phenomenological plasticity models [10,11].…”