A 3-D model for void evolution in viscous materials under large compressive deformation

Investigation on the void closure efficiency in cogging processes of the large ingot by using a 3-D void evolution model

“…The 3-D evolution model for ellipsoidal voids was established on the basis of multi-scale framework and representative volume element (RVE) by Feng and Cui (2015), and it was applied to investigate the evolution behavior of the void defects in the large ingot. This void evolution model is described as follows.…”

“…Therefore, it is necessary to further research the evolution behavior of the void under complex stress and strain state. Using the RVE method, Feng and Cui (2015) established a 3-D model to describe the evolution behavior of the arbitrary ellipsoidal void, considering the influences of load condition and instantaneous void shape changing. Combining this model with stress and strain distributions obtained in FE simulation, the evolution of void shape and volume can be predicted in all the regions of the ingot, without the need of embedded void geometries in the billet.…”

“…However, using a reasonable cogging process can improve the forming efficiency and utilize the workability of the press machine more effectively. The main purpose of this study is to perform a comprehensive investigation of the void closure efficiency in different cogging processes of the large ingot, by adopting the 3-D void evolution model established by Feng and Cui (2015). The actual void defects in the large ingot are treated as the prolate ellipsoidal voids, and the influences of void shape, position and stress-strain state on void closure efficiency are analyzed.…”

Influence of Lode angle on modelling of void closure in hot metal forming processes

“…The evolution of the initial void is studied with respect to various mechanical parameters, for dierent types of material. A large number of studies consider this approach (Zhang et al, 2009), (Saby et al, 2014a) and (Feng and Cui, 2015). Voids are typically assumed to be spherical or cylindrical.…”

“…Recently, (Feng and Cui, 2015) studied the evolution of dilute ellipsoidal void in power law viscous material under triaxial loading conditions. A semi-analytical expression was dened to predict void closure for large compressive strain.…”