A Continuum Framework for Finite Viscoplasticity and Classes of Flow Rules for Finite Viscoplasticity

Abstract

A continuum framework for finite viscoplasticity is developed based on Lee's multiplicative decomposition with internal variables. Noteworthy features include a thermodynamically consistent treatment of the storage of cold work and plastic volume change and a careful examination of the restrictions imposed by the entropy inequality and the property of instantaneous thermoelastic response. Classes of flow rules for finite viscoplasticity are defined by assuming that certain measures for plastic strain rate and plastic spin depend on the state variables but not on the plastic deformation. It is shown that three of these classes are mutually exclusive for finite elastic strains. For small elastic shear strains, two of the three classes are approximately equivalent. A number of exact and approximate kinematic relations between the various measures for plastic strain rate and plastic spin are derived. Some inconsistent flow rules encountered in the literature are also discussed. Throughout the paper, arbitrarily anisotropic materials are considered, and some of the simplifications resulting from the assumption of isotropy are noted.

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 2003
Accession Number
ADA418246

Entities

People

  • Mike Scheidler
  • T. W. Wright

Organizations

  • United States Army Research Laboratory

Tags

DTIC Thesaurus Topics

  • Continuum Mechanics
  • Crystal Lattices
  • Crystal Structure
  • Crystals
  • Elastic Properties
  • Materials
  • Mechanical Properties
  • Mechanical Working
  • Mechanics
  • Plastic Deformation
  • Plastic Flow
  • Plastic Properties
  • Strain Rate
  • Stress Strain Relations
  • Temperature Gradients
  • Thermodynamics
  • Viscoplasticity

Readers

  • Mathematical Modeling and Probability Theory.
  • Mechanical Engineering/Mechanics of Materials.
  • Theoretical Analysis.