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Title: A closure model for predicting crack growth under creep-fatigue loading

Abstract

A strip-yield model was formulated here to simulate creep-fatigue crack growth and to quantify the influence of hold time on plasticity-induced crack closure during creep-fatigue crack growth. Creep-fatigue experiments have shown that longer creep hold times result in faster crack growth rates in subsequent fatigue cycles. This model advances the idea that a decrease of plasticity-induced crack closure is experienced by the crack during fatigue loading when a longer hold time is applied each creep-fatigue cycle. Consequently, the crack tip experiences an increase in the effective stress intensity factor range causing faster growth rate during the fatigue loading. The weight function method was used to compute stress intensity factors and surface displacements for cracks embedded in a material experiencing elastic, plastic and creep deformations at elevated temperatures. It is shown that the longer the hold time, the larger the creep deformation and crack opening displacements in the near crack-tip region. In turn, this leads to a decrease in the crack-tip opening stress/load and faster crack growth rates during the subsequent fatigue cycle. The model was used to perform simulations of creep-fatigue crack growth at elevated temperatures in a nickel-base superalloy and AISI 316 austenitic steel.

Authors:
 [1]
  1. Univ. of Idaho, Moscow, ID (United States). Mechanical Engineering Dept.
Publication Date:
Research Org.:
Univ. of Idaho, Moscow, ID (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1502740
Grant/Contract Number:  
NE0008443
Resource Type:
Accepted Manuscript
Journal Name:
International Journal of Fatigue
Additional Journal Information:
Journal Name: International Journal of Fatigue; Journal ID: ISSN 0142-1123
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; creep fatigue; plasticity-induced crack closure; strip yield model; nickel base alloy; austenitic 316 steel

Citation Formats

Potirniche, Gabriel P. A closure model for predicting crack growth under creep-fatigue loading. United States: N. p., 2019. Web. doi:10.1016/j.ijfatigue.2019.03.029.
Potirniche, Gabriel P. A closure model for predicting crack growth under creep-fatigue loading. United States. doi:10.1016/j.ijfatigue.2019.03.029.
Potirniche, Gabriel P. Wed . "A closure model for predicting crack growth under creep-fatigue loading". United States. doi:10.1016/j.ijfatigue.2019.03.029.
@article{osti_1502740,
title = {A closure model for predicting crack growth under creep-fatigue loading},
author = {Potirniche, Gabriel P.},
abstractNote = {A strip-yield model was formulated here to simulate creep-fatigue crack growth and to quantify the influence of hold time on plasticity-induced crack closure during creep-fatigue crack growth. Creep-fatigue experiments have shown that longer creep hold times result in faster crack growth rates in subsequent fatigue cycles. This model advances the idea that a decrease of plasticity-induced crack closure is experienced by the crack during fatigue loading when a longer hold time is applied each creep-fatigue cycle. Consequently, the crack tip experiences an increase in the effective stress intensity factor range causing faster growth rate during the fatigue loading. The weight function method was used to compute stress intensity factors and surface displacements for cracks embedded in a material experiencing elastic, plastic and creep deformations at elevated temperatures. It is shown that the longer the hold time, the larger the creep deformation and crack opening displacements in the near crack-tip region. In turn, this leads to a decrease in the crack-tip opening stress/load and faster crack growth rates during the subsequent fatigue cycle. The model was used to perform simulations of creep-fatigue crack growth at elevated temperatures in a nickel-base superalloy and AISI 316 austenitic steel.},
doi = {10.1016/j.ijfatigue.2019.03.029},
journal = {International Journal of Fatigue},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {3}
}

Journal Article:
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This content will become publicly available on March 20, 2020
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