Abstract: This paper, first of all,
goes into the mechanism of necking deformation of a sheet metal
under plastic tension and, based on this using a constitutive
relation in form of non-quadratic orthotropic yield function, develop a predicting method for the right-side curves in
forming limit diagram of a sheet metal. In this part, the
criterion coming in the instable deformation process, the
developmental state of instable deformation process and the
conditions coming in the instable deformation state in form of
localized necking lines are searched for a sheet metal under
biaxial tensile stresses. In this analysis, the occurrent
mechanism of necking deformation of a sheet metal is searched
from the angel of minimal strain energy.
Key words:
Forming limit diagram Right-side
curves Instable deformation Localized necking line Minimal
strain energy
*
This project
is supported by National Natural Science Foundation of China
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