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Model Describing Material-Dependent Deformation Behavior in High-Velocity Metal Forming Processes

Hallberg, Håkan LU ; Ryttberg, Kristina and Ristinmaa, Matti LU (2009) In Journal of Engineering Mechanics 135(4). p.345-357
Abstract
A constitutive model for rate-dependent and thermomechanically coupled plasticity at finite strains is presented. The plasticity model is based on a J(2) model and rate-dependent behavior is included by use of a Perzyna-type formulation. Adiabatic heating effects are handled in a consistent way and not, as is a common assumption, through a constant conversion of the internal work rate into rate of heating. The conversion factor is instead derived from thermodynamic considerations. The stored energy is assumed to be a function of a single internal variable which differs from the effective plastic strain. This allows a thermodynamically consistent formulation to be obtained which, as shown, can be calibrated by use of simple procedures.... (More)
A constitutive model for rate-dependent and thermomechanically coupled plasticity at finite strains is presented. The plasticity model is based on a J(2) model and rate-dependent behavior is included by use of a Perzyna-type formulation. Adiabatic heating effects are handled in a consistent way and not, as is a common assumption, through a constant conversion of the internal work rate into rate of heating. The conversion factor is instead derived from thermodynamic considerations. The stored energy is assumed to be a function of a single internal variable which differs from the effective plastic strain. This allows a thermodynamically consistent formulation to be obtained which, as shown, can be calibrated by use of simple procedures. Choosing 100Cr6 steel in two differently heat treated conditions as prototype material, experimental tests are performed, enabling the model to be calibrated. Significant differences in deformation behavior are noted as the differently heat treated specimens are compared. In addition, the local stress-updating procedure is reduced to a single scalar equation, permitting a very efficient numerical implementation of the model. The constitutive formulation proposed was employed in an explicit finite element solver, illustrative simulations of a high-velocity metal forming process being performed to demonstrate the capabilities of the model and certain characteristic traits of the materials that were studied. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Engineering Mechanics
volume
135
issue
4
pages
345 - 357
publisher
American Society of Civil Engineers (ASCE)
external identifiers
  • wos:000264148000011
  • scopus:63049102729
ISSN
1943-7889
DOI
10.1061/(ASCE)0733-9399(2009)135:4(345)
language
English
LU publication?
yes
id
687d0180-7727-4898-bcda-ef0212b79c5e (old id 1404784)
date added to LUP
2009-06-15 09:47:39
date last changed
2017-03-12 03:37:59
@article{687d0180-7727-4898-bcda-ef0212b79c5e,
  abstract     = {A constitutive model for rate-dependent and thermomechanically coupled plasticity at finite strains is presented. The plasticity model is based on a J(2) model and rate-dependent behavior is included by use of a Perzyna-type formulation. Adiabatic heating effects are handled in a consistent way and not, as is a common assumption, through a constant conversion of the internal work rate into rate of heating. The conversion factor is instead derived from thermodynamic considerations. The stored energy is assumed to be a function of a single internal variable which differs from the effective plastic strain. This allows a thermodynamically consistent formulation to be obtained which, as shown, can be calibrated by use of simple procedures. Choosing 100Cr6 steel in two differently heat treated conditions as prototype material, experimental tests are performed, enabling the model to be calibrated. Significant differences in deformation behavior are noted as the differently heat treated specimens are compared. In addition, the local stress-updating procedure is reduced to a single scalar equation, permitting a very efficient numerical implementation of the model. The constitutive formulation proposed was employed in an explicit finite element solver, illustrative simulations of a high-velocity metal forming process being performed to demonstrate the capabilities of the model and certain characteristic traits of the materials that were studied.},
  author       = {Hallberg, Håkan and Ryttberg, Kristina and Ristinmaa, Matti},
  issn         = {1943-7889},
  language     = {eng},
  number       = {4},
  pages        = {345--357},
  publisher    = {American Society of Civil Engineers (ASCE)},
  series       = {Journal of Engineering Mechanics},
  title        = {Model Describing Material-Dependent Deformation Behavior in High-Velocity Metal Forming Processes},
  url          = {http://dx.doi.org/10.1061/(ASCE)0733-9399(2009)135:4(345)},
  volume       = {135},
  year         = {2009},
}