TY - JOUR

T1 - A methodology for performing and evaluating miniaturized wedge splitting tests accompanied by digital image correlation

AU - Fruhstorfer, Jens

AU - Gruber, Dietmar

N1 - Publisher Copyright: © 2023 The Author(s)

PY - 2023/5/30

Y1 - 2023/5/30

N2 - This methodology study investigated the application of a miniaturized wedge splitting test (WST) accompanied by digital image correlation (DIC) for the novel analysis of fracture mechanisms occurring during fracture of quasi-brittle refractories. Results from representative miniaturized WST were compared to standard WST results. Accuracy was improved by excluding experiments where unstable crack growth occurred or when the crack propagated perpendicular to the notch direction. Besides a sample size effect, a limitation of the fracture process zone (FPZ) size occurred. This FPZ limitation reduced the specific fracture energy G‘F from 112.4 N/m for the standard WST to 55.4 N/m for the miniaturized WST. Due to the sample size effect, the brittleness number was 0.194 and lower than for the standard WST with 0.414. The miniaturized WST enabled a more detailed evaluation of the acting mechanisms by analyzing the load–displacement curves together with the DIC. Grain bridging, microcracking, crack deflection/branching mechanisms and friction effects were evaluable. The analysis of the miniaturized WST could prove the supposed mechanisms acting during the standard WST. However, not all observed mechanisms also occurred in the standard WST due to the difference in the samples' brittleness.

AB - This methodology study investigated the application of a miniaturized wedge splitting test (WST) accompanied by digital image correlation (DIC) for the novel analysis of fracture mechanisms occurring during fracture of quasi-brittle refractories. Results from representative miniaturized WST were compared to standard WST results. Accuracy was improved by excluding experiments where unstable crack growth occurred or when the crack propagated perpendicular to the notch direction. Besides a sample size effect, a limitation of the fracture process zone (FPZ) size occurred. This FPZ limitation reduced the specific fracture energy G‘F from 112.4 N/m for the standard WST to 55.4 N/m for the miniaturized WST. Due to the sample size effect, the brittleness number was 0.194 and lower than for the standard WST with 0.414. The miniaturized WST enabled a more detailed evaluation of the acting mechanisms by analyzing the load–displacement curves together with the DIC. Grain bridging, microcracking, crack deflection/branching mechanisms and friction effects were evaluable. The analysis of the miniaturized WST could prove the supposed mechanisms acting during the standard WST. However, not all observed mechanisms also occurred in the standard WST due to the difference in the samples' brittleness.

KW - Digital image correlation

KW - Fracture mechanisms

KW - Microscopy

KW - Refractories

KW - Wedge splitting test

UR - http://www.scopus.com/inward/record.url?scp=85163295483&partnerID=8YFLogxK

U2 - 10.1016/j.engfracmech.2023.109357

DO - 10.1016/j.engfracmech.2023.109357

M3 - Article

AN - SCOPUS:85163295483

VL - 288.2023

JO - Engineering Fracture Mechanics

JF - Engineering Fracture Mechanics

SN - 0013-7944

IS - 4 August

M1 - 109357

ER -