Initiation and Fracture Characteristics of Different Width Cracks of Concretes under Compressional Loading
A stress concentration at a crack tip may cause fracture initiation even under low-stress conditions. The maximum axial stress theory meets the challenges of explaining the fracture propagation of a non-closed fracture of cracked concretes under compressional loading. Uniaxial loading tests of singl...
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MDPI AG
2022-05-01
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| Online Access: | https://www.mdpi.com/2076-3417/12/10/4803 |
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| author | Lizhou Wu Jianting Zhou Jun Yang Jingzhou Xin Hong Zhang Bu Li |
| author_facet | Lizhou Wu Jianting Zhou Jun Yang Jingzhou Xin Hong Zhang Bu Li |
| author_sort | Lizhou Wu |
| collection | DOAJ |
| description | A stress concentration at a crack tip may cause fracture initiation even under low-stress conditions. The maximum axial stress theory meets the challenges of explaining the fracture propagation of a non-closed fracture of cracked concretes under compressional loading. Uniaxial loading tests of single-crack concrete specimens were carried out and a numerical simulation of fracture propagation under uniaxial compression was performed. The radial shear stress criterion for a mode-II fracture is proposed to examine the stress intensity factor (SIF) of the pre-crack specimens under compressional loading. When the maximum radial shear stress at the crack tip is larger than the maximum axial tensile stress, and the maximum dimensionless SIFs can satisfy <i>f<sub>rθ</sub></i><sub>max</sub>/<i>f<sub>θ</sub></i><sub>max</sub> > 1 and <i>f<sub>rθ</sub></i><sub>max</sub>/<i>f<sub>θ</sub></i><sub>max</sub> > <i>K</i><sub>IIC</sub>/<i>K</i><sub>IC</sub> (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>f</mi><mrow><mi>θ</mi><mi>max</mi></mrow></msub><mo>=</mo><mrow><mrow><msub><mi>K</mi><mrow><mi>Ie</mi></mrow></msub></mrow><mo>/</mo><mrow><msubsup><mi>σ</mi><mi>y</mi><mrow></mrow></msubsup></mrow></mrow><msqrt><mrow><mi>π</mi><mi>a</mi></mrow></msqrt></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>f</mi><mrow><mi>r</mi><mi>θ</mi><mi>max</mi></mrow></msub><mo>=</mo><mrow><mrow><msub><mi>K</mi><mrow><mrow><mi>II</mi><mi mathvariant="normal">e</mi></mrow></mrow></msub></mrow><mo>/</mo><mrow><msubsup><mi>σ</mi><mi>y</mi><mrow></mrow></msubsup></mrow></mrow><msqrt><mrow><mi>π</mi><mi>a</mi></mrow></msqrt></mrow></semantics></math></inline-formula> are maximum dimensionless mode-I and mode-II SIFs, respectively), the crack will extend along the direction of the maximum radial shear stress. The influence of the single-crack angle and width on the mechanical properties of the specimens was examined. The experimental and numerical results indicate that the existence of cracks can considerably weaken the strength of the specimen. The distribution and width of the cracks had a significant effect on the specimen strength. The strength of the concrete specimen initially decreased and then increased with increasing fracture angle. The failure mechanism and rupture angle of pre-crack brittle material while considering crack width will be discovered. |
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| spelling | doaj.art-c0a2ab418b7d4715a9fcb35291f79ad12023-11-23T09:53:26ZengMDPI AGApplied Sciences2076-34172022-05-011210480310.3390/app12104803Initiation and Fracture Characteristics of Different Width Cracks of Concretes under Compressional LoadingLizhou Wu0Jianting Zhou1Jun Yang2Jingzhou Xin3Hong Zhang4Bu Li5State Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing Jiaotong University, Chongqing 400074, ChinaState Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing Jiaotong University, Chongqing 400074, ChinaState Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing Jiaotong University, Chongqing 400074, ChinaState Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing Jiaotong University, Chongqing 400074, ChinaState Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing Jiaotong University, Chongqing 400074, ChinaChina Southwest Geotechnical Investigation & Design Institute Co., Ltd., Chengdu 610052, ChinaA stress concentration at a crack tip may cause fracture initiation even under low-stress conditions. The maximum axial stress theory meets the challenges of explaining the fracture propagation of a non-closed fracture of cracked concretes under compressional loading. Uniaxial loading tests of single-crack concrete specimens were carried out and a numerical simulation of fracture propagation under uniaxial compression was performed. The radial shear stress criterion for a mode-II fracture is proposed to examine the stress intensity factor (SIF) of the pre-crack specimens under compressional loading. When the maximum radial shear stress at the crack tip is larger than the maximum axial tensile stress, and the maximum dimensionless SIFs can satisfy <i>f<sub>rθ</sub></i><sub>max</sub>/<i>f<sub>θ</sub></i><sub>max</sub> > 1 and <i>f<sub>rθ</sub></i><sub>max</sub>/<i>f<sub>θ</sub></i><sub>max</sub> > <i>K</i><sub>IIC</sub>/<i>K</i><sub>IC</sub> (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>f</mi><mrow><mi>θ</mi><mi>max</mi></mrow></msub><mo>=</mo><mrow><mrow><msub><mi>K</mi><mrow><mi>Ie</mi></mrow></msub></mrow><mo>/</mo><mrow><msubsup><mi>σ</mi><mi>y</mi><mrow></mrow></msubsup></mrow></mrow><msqrt><mrow><mi>π</mi><mi>a</mi></mrow></msqrt></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>f</mi><mrow><mi>r</mi><mi>θ</mi><mi>max</mi></mrow></msub><mo>=</mo><mrow><mrow><msub><mi>K</mi><mrow><mrow><mi>II</mi><mi mathvariant="normal">e</mi></mrow></mrow></msub></mrow><mo>/</mo><mrow><msubsup><mi>σ</mi><mi>y</mi><mrow></mrow></msubsup></mrow></mrow><msqrt><mrow><mi>π</mi><mi>a</mi></mrow></msqrt></mrow></semantics></math></inline-formula> are maximum dimensionless mode-I and mode-II SIFs, respectively), the crack will extend along the direction of the maximum radial shear stress. The influence of the single-crack angle and width on the mechanical properties of the specimens was examined. The experimental and numerical results indicate that the existence of cracks can considerably weaken the strength of the specimen. The distribution and width of the cracks had a significant effect on the specimen strength. The strength of the concrete specimen initially decreased and then increased with increasing fracture angle. The failure mechanism and rupture angle of pre-crack brittle material while considering crack width will be discovered.https://www.mdpi.com/2076-3417/12/10/4803crackconcrete materialuniaxial compressionstrengthmixed-mode fracture criterion |
| spellingShingle | Lizhou Wu Jianting Zhou Jun Yang Jingzhou Xin Hong Zhang Bu Li Initiation and Fracture Characteristics of Different Width Cracks of Concretes under Compressional Loading Applied Sciences crack concrete material uniaxial compression strength mixed-mode fracture criterion |
| title | Initiation and Fracture Characteristics of Different Width Cracks of Concretes under Compressional Loading |
| title_full | Initiation and Fracture Characteristics of Different Width Cracks of Concretes under Compressional Loading |
| title_fullStr | Initiation and Fracture Characteristics of Different Width Cracks of Concretes under Compressional Loading |
| title_full_unstemmed | Initiation and Fracture Characteristics of Different Width Cracks of Concretes under Compressional Loading |
| title_short | Initiation and Fracture Characteristics of Different Width Cracks of Concretes under Compressional Loading |
| title_sort | initiation and fracture characteristics of different width cracks of concretes under compressional loading |
| topic | crack concrete material uniaxial compression strength mixed-mode fracture criterion |
| url | https://www.mdpi.com/2076-3417/12/10/4803 |
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