...Rolf Sandström; Fangfei Sui For a long time, only empirical models existed for creep curves in the tertiary stage. To understand the role of creep damage, including changes in the dislocation structure, cavitation, and necking, basic models that do not involve adjustable parameters have, however...

... to this is provided based on the increase in dislocation density and necking in the tested specimens during high strain rate loading and the consequent stress wave attenuation as it propagates within the specimen. The fracture behavior and effect of high strain rate testing on microstructure changes are examined...

... demonstrates strain localization that is in agreement with the locations of diffuse necks in experimental observations. The tests are conducted using a federated multiple-program multiple-data simulation, which allows for load balancing between the coarse and fine scale calculations. Such a simulation...

...C. Hari Manoj Simha; Javad Gholipour; Alexander Bardelcik; Michael J. Worswick This paper presents an extended stress-based forming limit curve (XSFLC) that can be used to predict the onset of necking in sheet metal loaded under non-proportional load paths, as well as under three-dimensional stress...

.... With the aid of the acquired data, finite element simulations for analyzing the forming process of TWBs were carried out using a general purpose finite element package, LS-DYNA. A localized necking criterion based on the vertex theory was employed to predict forming limit strains and failure locations...

...C. L. Chow; M. Jie; X. Wu The paper presents the development of a localized necking criterion based on the singularity of acoustic tensor. This criterion is applicable to materials exhibiting strain-softening behavior. The tensor form of the criterion is deployed in simple mathematical expressions...

...I. Scheider; W. Brocks; A. Cornec The problem of determining true stress-strain curves from flat tensile specimens beyond the onset of necking has been investigated based on finite element analyses under consideration of experimental accessible data using digital image correlation (DIC...

... to characterize the localized necking (or localized bifurcation) mechanism in elastoplastic materials. The plastic anisotropy of materials is considered. A generalized deformation theory of plasticity is proposed. The theory considers Hosford’s high-order yield criterion (1979), Hill’s quadratic yield criterion...

.... For the prediction of limit strains under nonproportional loading, a damage criterion for localized necking of sheet metals subjected to complex strain history is proposed. The model is employed to predict the FLDs of AL6111-T4 alloy. The predicted results agree well with those determined experimentally...

...Xinhai Zhu; Klaus Weinmann, Fellow ASME; Abhijit Chandra, Fellow ASME The purpose of this study is to determine analytically the orientations of localized necks occurring in sheet metal forming processes, and obtain the corresponding forming limit diagrams (FLDs). In addition to the force...

... and damage behaviors. With the aid of the damage viscoplastic potential, the damage evolution equations are established. Based on a proposed damage criterion for localized necking, the model is employed to predict the FLC of aluminum 6111-T4 sheet alloy. The predicted results agree well with those determined...

...Thomas B. Stoughton A strain-based forming limit criterion is widely used throughout the sheet-metal forming industry to gauge the stability of the deformed material with respect to the development of a localized neck prior to fracture. This criterion is strictly valid only when the strain path...