A rate independent inelasticity model with smooth transition for unifying low-cycle to high-cycle fatigue life prediction

F. Mozafari, T Prakash G. Thamburaja, A. R. Srinivasa, N. Moslemi

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

A three-dimensional rate independent inelastic constitutive model has been developed to predict the fatigue behavior of metals spanning low to high cycles, based solely on the monotonic stress strain curve and a cyclic test for a few cycles ( < 1000). The key to the development of the model is that the “microplastic response” before full yield is accounted for by a new approach to inelastic modeling while retaining a rate independent response. A numerical algorithm based on the one-dimensional version of the constitutive theory has also been implemented into a computer code to model fatigue loading under simple tension/compression i.e. uniaxial loading conditions. The material parameters in the constitutive model were calibrated through fitting the constitutive model to the monotonic stress–strain curve obtained from a simple compression test experiment. By adopting the total inelastic work dissipation (which is related to the configurational entropy created due to damage) as the failure criteria and integrating the rate of entropy generation (under isothermal conditions) over a typical stabilized hysteresis cycle (including the small scale effects due to microplasticity), a close-formed expression for stress-fatigue life prediction is also derived for zero mean stress. Finally, it is shown that the model and numerical algorithm are able to predict the experimental stress-life and strain-life (with and without mean stress) responses quite well.

Original languageEnglish
Pages (from-to)325-335
Number of pages11
JournalInternational Journal of Mechanical Sciences
Volume159
DOIs
Publication statusPublished - 1 Aug 2019

Fingerprint

fatigue life
Constitutive models
Fatigue of materials
cycles
predictions
Entropy
Stress-strain curves
entropy
Hysteresis
scale effect
Compaction
compression tests
Metals
curves
retaining
dissipation
hysteresis
damage
computer programs
Experiments

Keywords

  • Computational implementation
  • Experimental investigation
  • Fatigue
  • Plasticity modeling

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

A rate independent inelasticity model with smooth transition for unifying low-cycle to high-cycle fatigue life prediction. / Mozafari, F.; G. Thamburaja, T Prakash; Srinivasa, A. R.; Moslemi, N.

In: International Journal of Mechanical Sciences, Vol. 159, 01.08.2019, p. 325-335.

Research output: Contribution to journalArticle

@article{0d4865c38d244ac98417808b331d83eb,
title = "A rate independent inelasticity model with smooth transition for unifying low-cycle to high-cycle fatigue life prediction",
abstract = "A three-dimensional rate independent inelastic constitutive model has been developed to predict the fatigue behavior of metals spanning low to high cycles, based solely on the monotonic stress strain curve and a cyclic test for a few cycles ( < 1000). The key to the development of the model is that the “microplastic response” before full yield is accounted for by a new approach to inelastic modeling while retaining a rate independent response. A numerical algorithm based on the one-dimensional version of the constitutive theory has also been implemented into a computer code to model fatigue loading under simple tension/compression i.e. uniaxial loading conditions. The material parameters in the constitutive model were calibrated through fitting the constitutive model to the monotonic stress–strain curve obtained from a simple compression test experiment. By adopting the total inelastic work dissipation (which is related to the configurational entropy created due to damage) as the failure criteria and integrating the rate of entropy generation (under isothermal conditions) over a typical stabilized hysteresis cycle (including the small scale effects due to microplasticity), a close-formed expression for stress-fatigue life prediction is also derived for zero mean stress. Finally, it is shown that the model and numerical algorithm are able to predict the experimental stress-life and strain-life (with and without mean stress) responses quite well.",
keywords = "Computational implementation, Experimental investigation, Fatigue, Plasticity modeling",
author = "F. Mozafari and {G. Thamburaja}, {T Prakash} and Srinivasa, {A. R.} and N. Moslemi",
year = "2019",
month = "8",
day = "1",
doi = "10.1016/j.ijmecsci.2019.05.017",
language = "English",
volume = "159",
pages = "325--335",
journal = "International Journal of Mechanical Sciences",
issn = "0020-7403",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - A rate independent inelasticity model with smooth transition for unifying low-cycle to high-cycle fatigue life prediction

AU - Mozafari, F.

AU - G. Thamburaja, T Prakash

AU - Srinivasa, A. R.

AU - Moslemi, N.

PY - 2019/8/1

Y1 - 2019/8/1

N2 - A three-dimensional rate independent inelastic constitutive model has been developed to predict the fatigue behavior of metals spanning low to high cycles, based solely on the monotonic stress strain curve and a cyclic test for a few cycles ( < 1000). The key to the development of the model is that the “microplastic response” before full yield is accounted for by a new approach to inelastic modeling while retaining a rate independent response. A numerical algorithm based on the one-dimensional version of the constitutive theory has also been implemented into a computer code to model fatigue loading under simple tension/compression i.e. uniaxial loading conditions. The material parameters in the constitutive model were calibrated through fitting the constitutive model to the monotonic stress–strain curve obtained from a simple compression test experiment. By adopting the total inelastic work dissipation (which is related to the configurational entropy created due to damage) as the failure criteria and integrating the rate of entropy generation (under isothermal conditions) over a typical stabilized hysteresis cycle (including the small scale effects due to microplasticity), a close-formed expression for stress-fatigue life prediction is also derived for zero mean stress. Finally, it is shown that the model and numerical algorithm are able to predict the experimental stress-life and strain-life (with and without mean stress) responses quite well.

AB - A three-dimensional rate independent inelastic constitutive model has been developed to predict the fatigue behavior of metals spanning low to high cycles, based solely on the monotonic stress strain curve and a cyclic test for a few cycles ( < 1000). The key to the development of the model is that the “microplastic response” before full yield is accounted for by a new approach to inelastic modeling while retaining a rate independent response. A numerical algorithm based on the one-dimensional version of the constitutive theory has also been implemented into a computer code to model fatigue loading under simple tension/compression i.e. uniaxial loading conditions. The material parameters in the constitutive model were calibrated through fitting the constitutive model to the monotonic stress–strain curve obtained from a simple compression test experiment. By adopting the total inelastic work dissipation (which is related to the configurational entropy created due to damage) as the failure criteria and integrating the rate of entropy generation (under isothermal conditions) over a typical stabilized hysteresis cycle (including the small scale effects due to microplasticity), a close-formed expression for stress-fatigue life prediction is also derived for zero mean stress. Finally, it is shown that the model and numerical algorithm are able to predict the experimental stress-life and strain-life (with and without mean stress) responses quite well.

KW - Computational implementation

KW - Experimental investigation

KW - Fatigue

KW - Plasticity modeling

UR - http://www.scopus.com/inward/record.url?scp=85067173473&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85067173473&partnerID=8YFLogxK

U2 - 10.1016/j.ijmecsci.2019.05.017

DO - 10.1016/j.ijmecsci.2019.05.017

M3 - Article

VL - 159

SP - 325

EP - 335

JO - International Journal of Mechanical Sciences

JF - International Journal of Mechanical Sciences

SN - 0020-7403

ER -