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Effects of elastic unloading on multiple necking in tensile bars

Nilsson, Kristina LU (2004) In International Journal of Impact Engineering 30(10). p.1353-1367
Abstract
The deformation of round tensile bars subject to dynamic loading is studied numerically using two different plasticity theories: J(2)-flow theory and J(2)-deformation theory. Time development of neck localization is visualized and a comparison of the necking patterns obtained using the two different constitutive models is presented. The possibility of using J(2)-deformation theory as an alternative to J(2)-flow theory to model the dynamic behaviour of tensile bars subject to high rate deformation is investigated and the effects of elastic unloading are discussed. Influence of specimen geometry and initial thickness imperfections is also considered. The effects of elastic unloading on multiple necking are of particular interest, since... (More)
The deformation of round tensile bars subject to dynamic loading is studied numerically using two different plasticity theories: J(2)-flow theory and J(2)-deformation theory. Time development of neck localization is visualized and a comparison of the necking patterns obtained using the two different constitutive models is presented. The possibility of using J(2)-deformation theory as an alternative to J(2)-flow theory to model the dynamic behaviour of tensile bars subject to high rate deformation is investigated and the effects of elastic unloading are discussed. Influence of specimen geometry and initial thickness imperfections is also considered. The effects of elastic unloading on multiple necking are of particular interest, since elastic unloading may serve as a restricting factor regarding the growth of multiple neck localizations. In the present analysis, multiple necking is found to appear using both J(2)-flow theory and J(2)-deformation theory. The use of stubby bars leads to similar necking patterns when comparing the results obtained with J(2)-flow theory and J(2)-deformation theory. For slender bars subject to certain loading conditions a larger number of necks is obtained when J(2)-deformation theory is applied rather than J(2)-flow theory. In addition, results of simulations near the ideal-plastic limit are discussed as well as results where the yield stress is varied. (C) 2003 Elsevier Ltd. All rights reserved. (Less)
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author
organization
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Contribution to journal
publication status
published
subject
keywords
elastic unloading, numerical, J(2)-flow theory and J(2)-deformation theory, analysis, dynamic response, multiple necking
in
International Journal of Impact Engineering
volume
30
issue
10
pages
1353 - 1367
publisher
Elsevier
external identifiers
  • wos:000224181300005
  • scopus:4344609705
ISSN
1879-3509
DOI
10.1016/j.ijimpeng.2003.10.035
language
English
LU publication?
yes
id
dd6f0938-9709-4ad0-b038-cd794dd00be7 (old id 265398)
date added to LUP
2007-10-29 09:24:48
date last changed
2017-02-12 03:34:47
@article{dd6f0938-9709-4ad0-b038-cd794dd00be7,
  abstract     = {The deformation of round tensile bars subject to dynamic loading is studied numerically using two different plasticity theories: J(2)-flow theory and J(2)-deformation theory. Time development of neck localization is visualized and a comparison of the necking patterns obtained using the two different constitutive models is presented. The possibility of using J(2)-deformation theory as an alternative to J(2)-flow theory to model the dynamic behaviour of tensile bars subject to high rate deformation is investigated and the effects of elastic unloading are discussed. Influence of specimen geometry and initial thickness imperfections is also considered. The effects of elastic unloading on multiple necking are of particular interest, since elastic unloading may serve as a restricting factor regarding the growth of multiple neck localizations. In the present analysis, multiple necking is found to appear using both J(2)-flow theory and J(2)-deformation theory. The use of stubby bars leads to similar necking patterns when comparing the results obtained with J(2)-flow theory and J(2)-deformation theory. For slender bars subject to certain loading conditions a larger number of necks is obtained when J(2)-deformation theory is applied rather than J(2)-flow theory. In addition, results of simulations near the ideal-plastic limit are discussed as well as results where the yield stress is varied. (C) 2003 Elsevier Ltd. All rights reserved.},
  author       = {Nilsson, Kristina},
  issn         = {1879-3509},
  keyword      = {elastic unloading,numerical,J(2)-flow theory and J(2)-deformation theory,analysis,dynamic response,multiple necking},
  language     = {eng},
  number       = {10},
  pages        = {1353--1367},
  publisher    = {Elsevier},
  series       = {International Journal of Impact Engineering},
  title        = {Effects of elastic unloading on multiple necking in tensile bars},
  url          = {http://dx.doi.org/10.1016/j.ijimpeng.2003.10.035},
  volume       = {30},
  year         = {2004},
}