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Thermo-Mechanical Fatigue Lifetime Assessment of Spheroidal Cast Iron at Different Thermal Constraint Levels. / Ghodrat, Sepideh; Kalra, Aakarshit; Kestens, Leo; Riemslag, Ton.

In: Metals, Vol. 9, No. 10, 1068, 2019.

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@article{5c528b14d5d04849998e9ae4f95ee3f4,
title = "Thermo-Mechanical Fatigue Lifetime Assessment of Spheroidal Cast Iron at Different Thermal Constraint Levels",
abstract = "In previous work on the thermo-mechanical fatigue (TMF) of compacted graphite iron (CGI), lifetimes measured under total constraint were confirmed analytically by numerical integration of Paris{\textquoteright} crack-growth law. In current work, the results for CGI are further validated for spheroidal cast iron (SGI), while TMF tests at different constraint levels were additionally performed. The Paris crack-growth law is found to require a different CParis parameter value per distinct constraint level, indicating that Paris{\textquoteright} law does not capture all physical backgrounds of TMF crack growth, such as the effect of constraint level. An adapted version of Paris{\textquoteright} law is developed, designated as the local strain model. The new model considers cyclic plastic strains at the crack tip to control crack growth and is found to predict TMF lifetimes of SGI very well for all constraint levels with a single set of parameters. This includes not only full constraint but also over and partial constraint conditions, as encountered in diesel engine service conditions. The local strain model considers the crack tip to experience a distinct sharpening and blunting stage during each TMF cycle, with separate contributions to crack-tip plasticity, originating from cyclic bulk stresses in the sharpening stage and cyclic plastic bulk strains in the blunting stage. ",
keywords = "thermo-mechanical fatigue, spheroidal cast iron, partial constraint, crack growth models, crack-tip cyclic plasticity, crack-tip blunting and sharpening",
author = "Sepideh Ghodrat and Aakarshit Kalra and Leo Kestens and Ton Riemslag",
year = "2019",
doi = "10.3390/met9101068",
language = "English",
volume = "9",
journal = "Metals",
issn = "2075-4701",
publisher = "MDPI",
number = "10",

}

RIS

TY - JOUR

T1 - Thermo-Mechanical Fatigue Lifetime Assessment of Spheroidal Cast Iron at Different Thermal Constraint Levels

AU - Ghodrat, Sepideh

AU - Kalra, Aakarshit

AU - Kestens, Leo

AU - Riemslag, Ton

PY - 2019

Y1 - 2019

N2 - In previous work on the thermo-mechanical fatigue (TMF) of compacted graphite iron (CGI), lifetimes measured under total constraint were confirmed analytically by numerical integration of Paris’ crack-growth law. In current work, the results for CGI are further validated for spheroidal cast iron (SGI), while TMF tests at different constraint levels were additionally performed. The Paris crack-growth law is found to require a different CParis parameter value per distinct constraint level, indicating that Paris’ law does not capture all physical backgrounds of TMF crack growth, such as the effect of constraint level. An adapted version of Paris’ law is developed, designated as the local strain model. The new model considers cyclic plastic strains at the crack tip to control crack growth and is found to predict TMF lifetimes of SGI very well for all constraint levels with a single set of parameters. This includes not only full constraint but also over and partial constraint conditions, as encountered in diesel engine service conditions. The local strain model considers the crack tip to experience a distinct sharpening and blunting stage during each TMF cycle, with separate contributions to crack-tip plasticity, originating from cyclic bulk stresses in the sharpening stage and cyclic plastic bulk strains in the blunting stage.

AB - In previous work on the thermo-mechanical fatigue (TMF) of compacted graphite iron (CGI), lifetimes measured under total constraint were confirmed analytically by numerical integration of Paris’ crack-growth law. In current work, the results for CGI are further validated for spheroidal cast iron (SGI), while TMF tests at different constraint levels were additionally performed. The Paris crack-growth law is found to require a different CParis parameter value per distinct constraint level, indicating that Paris’ law does not capture all physical backgrounds of TMF crack growth, such as the effect of constraint level. An adapted version of Paris’ law is developed, designated as the local strain model. The new model considers cyclic plastic strains at the crack tip to control crack growth and is found to predict TMF lifetimes of SGI very well for all constraint levels with a single set of parameters. This includes not only full constraint but also over and partial constraint conditions, as encountered in diesel engine service conditions. The local strain model considers the crack tip to experience a distinct sharpening and blunting stage during each TMF cycle, with separate contributions to crack-tip plasticity, originating from cyclic bulk stresses in the sharpening stage and cyclic plastic bulk strains in the blunting stage.

KW - thermo-mechanical fatigue

KW - spheroidal cast iron

KW - partial constraint

KW - crack growth models

KW - crack-tip cyclic plasticity

KW - crack-tip blunting and sharpening

UR - http://www.scopus.com/inward/record.url?scp=85073510731&partnerID=8YFLogxK

U2 - 10.3390/met9101068

DO - 10.3390/met9101068

M3 - Article

VL - 9

JO - Metals

JF - Metals

SN - 2075-4701

IS - 10

M1 - 1068

ER -

ID: 57245526