Local fracture toughness testing of sandstone based on X-ray tomographic reconstruction

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378297%3A_____%2F21%3A00537395" target="_blank" >RIV/68378297:_____/21:00537395 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68145535:_____/21:00537395

Výsledek na webu

<a href="https://doi.org/10.1016/j.ijrmms.2020.104578" target="_blank" >https://doi.org/10.1016/j.ijrmms.2020.104578</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.ijrmms.2020.104578" target="_blank" >10.1016/j.ijrmms.2020.104578</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Local fracture toughness testing of sandstone based on X-ray tomographic reconstruction

Popis výsledku v původním jazyce

It is well known that the measured values of the fracture toughness of rocks are influenced by material heterogeneity, dimensions, boundary conditions, and asymmetric mechanical behavior. Consequently, the results obtained by standard testing methods developed primarily for homogenous materials with symmetric mechanical behavior, can significantly differ. The standard methods take global approach. Thus, they suppose that the material tested will follow a specific physical model and that one can consider the selected testing method as a black box in which some simple characteristics are measured and the required values can be evaluated. If the material behavior is too different from the theoretically expected one, this global approach will fail. The authors present a method called Local Fracture Toughness Testing (LFTT) to overcome these obstacles. LFFT is calculated independently of the boundary conditions and the crack length. LFTT is based on a complex methodology using a series of tomographic reconstructions, for which data are recorded during specimen loading. Subsequent extended data processing using digital image correlation serves for calculating the evolution of the displacement/ strain fields and for identifying the crack which develops during increased loading. Later on, the crack tip opening displacement and the local fracture toughness KIC are calculated at arbitrarily selected positions independent of the geometry and boundary conditions. The LFTT methodology was tested on a sandstone specimen, since such material is usually considered to be brittle. In this work, the authors demonstrate that even a stable crack extension can be identified after maximal loading. Using a loading machine developed in-house, the experimental data allowed for the measurement of fracture toughness at five loading levels/crack lengths. In addition, fracture toughness was measured in nine planes crossing the crack tip for each loading level.n

Název v anglickém jazyce

Local fracture toughness testing of sandstone based on X-ray tomographic reconstruction

Popis výsledku anglicky

It is well known that the measured values of the fracture toughness of rocks are influenced by material heterogeneity, dimensions, boundary conditions, and asymmetric mechanical behavior. Consequently, the results obtained by standard testing methods developed primarily for homogenous materials with symmetric mechanical behavior, can significantly differ. The standard methods take global approach. Thus, they suppose that the material tested will follow a specific physical model and that one can consider the selected testing method as a black box in which some simple characteristics are measured and the required values can be evaluated. If the material behavior is too different from the theoretically expected one, this global approach will fail. The authors present a method called Local Fracture Toughness Testing (LFTT) to overcome these obstacles. LFFT is calculated independently of the boundary conditions and the crack length. LFTT is based on a complex methodology using a series of tomographic reconstructions, for which data are recorded during specimen loading. Subsequent extended data processing using digital image correlation serves for calculating the evolution of the displacement/ strain fields and for identifying the crack which develops during increased loading. Later on, the crack tip opening displacement and the local fracture toughness KIC are calculated at arbitrarily selected positions independent of the geometry and boundary conditions. The LFTT methodology was tested on a sandstone specimen, since such material is usually considered to be brittle. In this work, the authors demonstrate that even a stable crack extension can be identified after maximal loading. Using a loading machine developed in-house, the experimental data allowed for the measurement of fracture toughness at five loading levels/crack lengths. In addition, fracture toughness was measured in nine planes crossing the crack tip for each loading level.n

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20302 - Applied mechanics

Projekt

<a href="/cs/project/EF16_019%2F0000766" target="_blank" >EF16_019/0000766: Inženýrské aplikace fyziky mikrosvěta</a><br>

Návaznosti

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

Rok uplatnění

2021

Kód důvěrnosti údajů

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

Název periodika

International Journal of Rock Mechanics and Mining Sciences

ISSN

1365-1609

e-ISSN

1873-4545

Svazek periodika

138

Číslo periodika v rámci svazku

February

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

17

Strana od-do

104578

Kód UT WoS článku

000620285300001

EID výsledku v databázi Scopus

2-s2.0-85098695463