Determination of critical criterion of tensile-shear failure in Brazilian disc based on theoretical analysis and meso-macro numerical simulation

Abstract To define the critical criterion between tensile failure and shear failure of Brazilian disc is crucial for determination of tensile strength under combination of tensile and compressive stresses. Although Griffith's tensile failure criterion is consistent with theoretical solution of radial splitting disc, there are still some shortcomings in which the compression-tension ratio is regarded as a constant and the critical criterion only depend on single parameter of tensile strength. Therefore a critical criterion for tensile-shear failure including tensile truncation was proposed firstly based on Mohr-Coulomb criterion. Then, a new calculation method of shear strength parameters was deduced based on the critical state stress circle. Finally, effective diameter and range of compression-tension ratio of Brazilian disc under tensile failure are proposed, and failure process of Brazilian disc from meso to macro is carried out based on numerical simulation. The results show that the modified Mohr-Coulomb criterion can be determined by two indexes of compressive strength and tensile strength. The deduced compression-tension ratio is in good agreement with experiment results. The accuracy of tensile strength test results is closely related to this ratio. When the ratio is greater than 6, failure of rock can be regarded as ideal tensile failure. If the ratio is less than 6, wedge-shape failure in loading area is the main failure type. On this condition, even if radial crack occurs, it is still not considered to be caused by pure tension.

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Parallel Offset Crack Interactions in Rock under Unloading Conditions

Advances in Materials Science and Engineering ◽

10.1155/2019/1430624 ◽

2019 ◽

Vol 2019 ◽

pp. 1-18 ◽

Cited By ~ 1

Author(s):

Zihan Zhou ◽

Zhonghui Chen

Keyword(s):

Numerical Simulation ◽

Theoretical Analysis ◽

Inclination Angle ◽

Shear Failure ◽

Superposition Principle ◽

Interaction Strength ◽

Jointed Rock ◽

Interaction Coefficient ◽

Open Pit ◽

Type I

Rock slopes contain numerous nonpenetrating intermittent joints which maintain stability under excavation disturbance. The tip interaction coefficient (IC) of parallel offset double cracks in a typical rock mass under unloading conditions was calculated in this study based on the superposition principle and fracture mechanics to determine the meso-influence law of intermittent joint interaction in the slope under the action of excavation. The influence of many factors on the said interaction was also analyzed theoretically. Lateral unloading tests were conducted on rock-like specimens with parallel offset cracks in addition to RFPA2D numerical simulation and theoretical analysis. The results show that a smaller length of rock bridge or staggered distance between the cracks results in more severe and sensitive interactions at the crack tip. The Type I interaction strength of the tip of the crack is not affected by the inclination angle of the crack, but shear failure gradually weakens as the angle changes. The shear failure of the tip of the crack is more sensitive to changes in the inclination angle when the cracks are closer to each other; the change is the most intense when α is about 60°. Lateral unloading test and RFPA2D numerical simulation results are in close agreement with the theoretical analysis, which validates the theoretical results. The current study shows the interaction of the parallel offset cracks in rock under unloading conditions and is conducive to the study of the meso-failure mechanism of the jointed rock slope in an open-pit mine under the action of excavation.

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Adhesives. Wood adhesives for non-structural applications. Determination of tensile shear strength of lap joints

10.3403/30315353u ◽

2017 ◽

Keyword(s):

Shear Strength ◽

Lap Joints ◽

Tensile Shear Strength ◽

Tensile Shear ◽

Wood Adhesives ◽

Structural Applications

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Theoretical Analysis and Numerical Simulation of GFRP Specimens' Defects Detection Using Infrared Thermal Wave Testing Technology Based on Linear Frequency Modulation Excitation

2020 5th International Conference on Mechanical, Control and Computer Engineering (ICMCCE) ◽

10.1109/icmcce51767.2020.00106 ◽

2020 ◽

Author(s):

Tang Qingju ◽

Wang Yunze

Keyword(s):

Numerical Simulation ◽

Theoretical Analysis ◽

Frequency Modulation ◽

Thermal Wave ◽

Linear Frequency Modulation ◽

Linear Frequency ◽

Testing Technology ◽

Modulation Excitation

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Determination of the critical system and data processing parameters for Raman-DIAL O3 and H2O measurements: numerical simulation

10.1117/12.364165 ◽

1999 ◽

Author(s):

Max Frioud ◽

Valentin Mitev ◽

Renaud Matthey

Keyword(s):

Numerical Simulation ◽

Data Processing ◽

Processing Parameters ◽

Critical System

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Optimal design of the solar tracking system of parabolic trough concentrating collectors

International Journal of Low-Carbon Technologies ◽

10.1093/ijlct/ctaa065 ◽

2020 ◽

Vol 15 (4) ◽

pp. 613-619

Author(s):

Li Kong ◽

Yunpeng Zhang ◽

Zhijian Lin ◽

Zhongzhu Qiu ◽

Chunying Li ◽

...

Keyword(s):

Numerical Simulation ◽

Solar Radiation ◽

Tracking System ◽

Low Cost ◽

Parabolic Trough ◽

The North ◽

Tracking Mode ◽

Solar Tracking ◽

East West

Abstract The present work aimed to select the optimum solar tracking mode for parabolic trough concentrating collectors using numerical simulation. The current work involved: (1) the calculation of daily solar radiation on the Earth’s surface, (2) the comparison of annual direct solar radiation received under different tracking modes and (3) the determination of optimum tilt angle for the north-south tilt tracking mode. It was found that the order of solar radiation received in Shanghai under the available tracking modes was: dual-axis tracking > north-south Earth’s axis tracking > north-south tilt tracking (β = 15°) > north-south tilt tracking (β = 45) > north-south horizontal tracking > east-west horizontal tracking. Single-axis solar tracking modes feature simple structures and low cost. This study also found that the solar radiation received under the north-south tilt tracking mode was higher than that of the north-south Earth’s axis tracking mode in 7 out of 12 months. Therefore, the north-south tilt tracking mode was studied separately to determine the corresponding optimum tilt angles in Haikou, Lhasa, Shanghai, Beijing and Hohhot, respectively, which were shown as follows: 18.81°, 27.29°, 28.67°, 36.21° and 37.97°.

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