Open AccessCalculation for tensile strength and fracture toughness of granite with three kinds of grain sizes using three-point-bending test
Author(s) -
Miao Yu,
Chenhui Wei,
Leilei Niu,
Shaohua Li,
Yang Yu
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0180880
Subject(s) - ultimate tensile strength , fracture toughness , materials science , microstructure , three point flexural test , bending , composite material , toughness , fracture (geology) , fractal , grain size , flexural strength , tensile testing , fracture mechanics , point (geometry) , structural engineering , geometry , mathematics , engineering , mathematical analysis
Tensile strength and fracture toughness, important parameters of the rock for engineering applications are difficult to measure. Thus this paper selected three kinds of granite samples (grain sizes = 1.01mm, 2.12mm and 3mm), used the combined experiments of physical and numerical simulation (RFPA-DIP version) to conduct three-point-bending (3-p-b) tests with different notches and introduced the acoustic emission monitor system to analyze the fracture mechanism around the notch tips. To study the effects of grain size on the tensile strength and toughness of rock samples, a modified fracture model was established linking fictitious crack to the grain size so that the microstructure of the specimens and fictitious crack growth can be considered together. The fractal method was introduced to represent microstructure of three kinds of granites and used to determine the length of fictitious crack. It is a simple and novel method to calculate the tensile strength and fracture toughness directly. Finally, the theoretical model was verified by the comparison to the numerical experiments by calculating the nominal strength σ n and maximum loads P max .