Determination of Fracture Toughness of Anisotropic Rocks by Boundary Element Method

Ke, Chien-Chung; Chen, Chao-Shi; Tu, Chih-Ho

doi:10.1007/s00603-005-0089-9

Cited by 81 publications

(21 citation statements)

References 38 publications

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“…Many investigations were typically focused in opening mode failure for crack growth (Alfano et al, 2009;Erdogan & Sih, 1963;Fowell et al, 1995;Lim et al, 1994;Yoshihara & Kawamura, 2006;Zhang, 2002;Zhou et al, 2012). The cracks in brittle materials are often vulnerable to compressive loading rather than tensile loading (Ke et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Numerical evaluation of mode I/II SIF of quasi-brittle materials using cracked semi-circular bend specimen

Fayed¹

2018

10.5267/j.esm

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An in-house finite element code was utilized to evaluate mode I/II stress intensity factor (SIF) of an edge cracked semi-circular disc subjected to three-point bending. The specimen was considered as an isotropic and homogeneous material. Relative span length ratios of 0.3 to 0.8 in steps of 0.1 were invoked. Relative crack length ratios of 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 were analyzed with crack angles up to 60° in steps of 5°. At the same crack length, mode I SIF decreases with increasing crack angle or decreasing the span length. The range of pure mode II decreases with increasing the span length. For the same crack length, the crack angle corresponding to the transition from a mixed mode I/II to a pure mode II increases with increasing the relative span length ratio. On the contrary, that angle decreases with increasing the crack length for the same span length. Good agreement has been generally obtained with relevant results found in the literature.

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Section: Introductionmentioning

confidence: 99%

Numerical evaluation of mode I/II SIF of quasi-brittle materials using cracked semi-circular bend specimen

Fayed¹

2018

10.5267/j.esm

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“…Many investigations have typically focused in the opening mode of crack extension . However, cracks in brittle materials are often subjected to compressive loading rather than tensile loading . Many applications of such materials show mixed mode I/II and/or pure mode II fracture.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8] However, cracks in brittle materials are often subjected to compressive loading rather than tensile loading. 9 Many applications of such materials show mixed mode I/II and/ or pure mode II fracture. Engineering designers are interested in crack growth in such materials.…”

Section: Introductionmentioning

confidence: 99%

“…Different methodologies exist in the literature to analyse diametrically compressed homogeneous isotropic Brazilian discs with inclined central cracks for the evaluation of their mixed mode K I and K II values. [9][10][11][19][20][21][22][23][24][25] Table 1 lists some researchers with the scope of their relevant researches in terms of the used methodology and the analysed relative crack length, a/R, θ and friction coefficient, μ. Here, R is the disc radius.…”

Section: Introductionmentioning

confidence: 99%

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Modes I/II SIF of a diametrically compressed Brazilian disc having a central inclined crack with frictional surfaces

Hammouda

Fayed

2017

Fatigue Fract Eng Mat Struct

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An in‐house finite element code was used to analyse a diametrically compressed isotropic homogeneous Brazilian disc having a central inclined crack with frictional surfaces for the evaluation of its corresponding modes I and II stress intensity factor (SIF). One‐half of the disc was successfully idealized. The coefficient of friction between the crack surfaces ranged from 0 to 1 in steps of 0.1. Relative crack length ratios of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 were analysed with crack angles up to 90° in steps of 5°. The crack angle corresponding to the transition from a mixed mode I/II to a pure mode II decreases with increasing the relative crack length ratio. An increase in the relative crack length ratio leads to an increase in the range of crack angles corresponding to a partially closed crack. The crack angle at which fully closed sliding crack surfaces commences is 30° independent of the relative crack length ratio and the friction coefficient. With the same relative crack length ratio and increasing the friction coefficient, there is a corresponding decrease in the crack angle for the maximum mode II SIF. With a decrease in the relative crack length ratio or the friction coefficient, the crack angle beyond which the crack surfaces become in a fully sticking mode decreases resulting in zero mode II SIF. Generally, mode II SIF decreases with increasing the friction coefficient between the crack surfaces. Good agreement has been generally obtained with relevant results found in the literature.

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“…The Brazilian tests on CSTBD specimens with a diameter of 7.4 cm, a thickness of 1 cm, and a crack length of 2.2 cm are conducted to observe the actual propagation paths and are compared with the numerical predictions. Details of the experimental procedure can be found in the paper by Ke et al [49]. The five elastic constants of anisotropic marble are E = 78.302 GPa, cracked specimens, the paths of crack propagation for AM-4, CM-4, DM-4, and EM-4 are shown in Figures 17, 19 of crack propagation paths between experimental observations and numerical predictions in AM4, CM-4, DM-4, and EM-4, respectively.…”

Section: Example 2 (Anisotropic Cracked Brazilian Disc Specimens Undementioning

confidence: 99%

Modeling crack propagation path of anisotropic rocks using boundary element method

Ke¹,

Chen

et al. 2008

Num Anal Meth Geomechanics

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SUMMARYIn a cracked material, the stress intensity factors (SIFs) at the crack tips, which govern the crack propagation and are associated with the strength of the material, are strongly affected by the crack inclination angle and the orientation with respect to the principal direction of anisotropy. In this paper, a formulation of the boundary element method (BEM), based on the relative displacements of the crack tip, is used to determine the mixed-mode SIFs of isotropic and anisotropic rocks. Numerical examples of the application of the formulation for different crack inclination angles, crack lengths, and degree of material anisotropy are presented. Furthermore, the BEM formulation combined with the maximum circumferential stress criterion is adopted to predict the crack initiation angles and simulate the crack propagation paths. The propagation path in cracked straight through Brazilian disc specimen is numerically predicted and the results of numerical and experimental data compared with the actual laboratory observations. Good agreement is found between the two approaches. The proposed BEM formulation is therefore suitable to simulate the process of crack propagation.

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Determination of Fracture Toughness of Anisotropic Rocks by Boundary Element Method

Cited by 81 publications

References 38 publications

Numerical evaluation of mode I/II SIF of quasi-brittle materials using cracked semi-circular bend specimen

Numerical evaluation of mode I/II SIF of quasi-brittle materials using cracked semi-circular bend specimen

Modes I/II SIF of a diametrically compressed Brazilian disc having a central inclined crack with frictional surfaces

Modeling crack propagation path of anisotropic rocks using boundary element method

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