Quantitative dependence of oxide-induced crack closure on air humidity for railway axle steel

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081723%3A_____%2F19%3A00506183" target="_blank" >RIV/68081723:_____/19:00506183 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216305:26620/19:PU135414

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0142112319300453?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0142112319300453?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.ijfatigue.2019.02.019" target="_blank" >10.1016/j.ijfatigue.2019.02.019</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Quantitative dependence of oxide-induced crack closure on air humidity for railway axle steel

Popis výsledku v původním jazyce

The paper analyses fatigue crack closure in the near-threshold regime of the EA4T railway axle steel. The dependence of fatigue crack growth threshold on air humidity was experimentally obtained. Varying air humidity led to changes of fatigue threshold values K-max,K-th in the range from 4 to 7 MPa m(0.5), which was explained by the effect of oxide-induced crack closure (OICC). Such a wide range of threshold values results in significant changes of residual fatigue lifetime of railway axles (by one or two orders of magnitude) operated under various humidity conditions. The Newman's model of plasticity-induced crack closure is not sufficient to explain high portions of crack closure near threshold and their variation, since roughness-induced crack closure (RICC) and OICC has also be taken into account. Detailed explanations and interpretations of the parameters quantifying crack closure are presented. A quantitative model for separation of the crack closure components was applied to threshold data from literature for dry and humid atmosphere as well as for new experimental data of the EA4T steel tested at various levels of humidity. The levels of OICC determined from threshold values were compared to those calculated from thicknesses of oxide debris measured on fracture surfaces. The oxide layers were measured after the experiments in scanning electron microscope using focused-ion-beam cuts. The results were plotted as dependences on absolute air humidity and were in a good agreement. Very low threshold values measured in dry air can occur in operation when the temperature is around 0 degrees C which is not exceptional in many countries.

Název v anglickém jazyce

Quantitative dependence of oxide-induced crack closure on air humidity for railway axle steel

Popis výsledku anglicky

The paper analyses fatigue crack closure in the near-threshold regime of the EA4T railway axle steel. The dependence of fatigue crack growth threshold on air humidity was experimentally obtained. Varying air humidity led to changes of fatigue threshold values K-max,K-th in the range from 4 to 7 MPa m(0.5), which was explained by the effect of oxide-induced crack closure (OICC). Such a wide range of threshold values results in significant changes of residual fatigue lifetime of railway axles (by one or two orders of magnitude) operated under various humidity conditions. The Newman's model of plasticity-induced crack closure is not sufficient to explain high portions of crack closure near threshold and their variation, since roughness-induced crack closure (RICC) and OICC has also be taken into account. Detailed explanations and interpretations of the parameters quantifying crack closure are presented. A quantitative model for separation of the crack closure components was applied to threshold data from literature for dry and humid atmosphere as well as for new experimental data of the EA4T steel tested at various levels of humidity. The levels of OICC determined from threshold values were compared to those calculated from thicknesses of oxide debris measured on fracture surfaces. The oxide layers were measured after the experiments in scanning electron microscope using focused-ion-beam cuts. The results were plotted as dependences on absolute air humidity and were in a good agreement. Very low threshold values measured in dry air can occur in operation when the temperature is around 0 degrees C which is not exceptional in many countries.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20306 - Audio engineering, reliability analysis

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

International Journal of Fatigue

ISSN

0142-1123

e-ISSN

—

Svazek periodika

123

Číslo periodika v rámci svazku

JUN

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

12

Strana od-do

213-224

Kód UT WoS článku

000463463600018

EID výsledku v databázi Scopus

2-s2.0-85061845913