Influences of notch width and notch-tip angle on the fracture toughness measurement using the semi-circular bend (SCB) specimen

Xu, Ying; Zhao, Guangyuan; Li, Xing; Wu, Bangbiao; Xia, Kaiwen

doi:10.1016/j.engfracmech.2023.109098

Cited by 16 publications

(3 citation statements)

References 52 publications

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“…The initial crack in the three-point bending (TPB) specimens was introduced using a thin diamond wire saw with a diameter of 0.3 mm to minimize the notch width effect on the fracture behavior of the rock specimens. 52 Based on the LEFM theory, the mode I and mode II stress intensity factors (K I and K II ) for the TPB specimen can be calculated by 50,51…”

Section: Rock Materials and Specimen Preparationmentioning

confidence: 99%

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Numerical investigation on the crack resistance curve of thermally treated quartz‐diorite rock under mixed mode I + II loading

Wu,

Yin,

Chen

et al. 2024

Fatigue Fract Eng Mat Struct

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To investigate the effects of thermal treatment and loading conditions on the crack initiation and propagation characteristics of quartz‐diorite, mixed mode I + II fracture tests were conducted by using three‐point bending (TPB) specimens. The numerical model, established on ABAQUS, couples the initial fracture toughness criterion and cohesive zone model to predict the crack initiation and propagation. The effects of thermal treatment and loading conditions on the crack propagation process, crack resistance curve, fracture path, and some fracture parameters at peak load have been analyzed and discussed. The results demonstrate that the thermal treatment has an obvious influence on the crack resistance curve of the specimen. The crack of the specimen will be dominated by the mode I fracture component with crack extension. The numerical results also show that the temperature and loading condition affect the crack length and fracture toughness at peak load.

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Section: Rock Materials and Specimen Preparationmentioning

confidence: 99%

“…These geometries are shown in Figure 1A. The initial crack in the three‐point bending (TPB) specimens was introduced using a thin diamond wire saw with a diameter of 0.3 mm to minimize the notch width effect on the fracture behavior of the rock specimens 52 …”

Section: Specimen Preparation and Experimental Programmentioning

confidence: 99%

Numerical investigation on the crack resistance curve of thermally treated quartz‐diorite rock under mixed mode I + II loading

Wu,

Yin,

Chen

et al. 2024

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

show abstract

“…[18], Xu Y. [19], and Ivan Gratchev [20] analyzed the rock damage process regarding fractures of different widths, discovering the relationship between fractures and rock formations and noting significant changes in fractures when they are smaller or larger than 1 mm. However, the aforementioned studies have presented significant variation in their crack-width measurements, thereby failing to comprehensively discuss the impact of crack width on the mechanical behavior of rocks within a suitable range.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Acoustic Emission Characteristics of Uniaxial Compression of MICP-Filled Sandstone

Fan

Wang

2023

Materials

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Rock masses are inherently heterogeneous, with numerous fractures that significantly affect their mechanical properties, fracture characteristics, and acoustic emission features due to the interactions between fractures or between fractures and the rock mass. Microbially induced calcite precipitation (MICP) technology, as an emerging non-destructive biological grouting reinforcement method, can repair fractured rock masses and alter their internal conditions. To investigate the mechanical properties, failure process evolution, and MICP repair effects of sandstone before and after repair, uniaxial compression tests were conducted on prefabricated, fractured (0.7–2.0 mm width) filled and unfilled rock samples, with acoustic emission monitoring throughout the process. Acoustic emission signal characteristics of the rock samples under stress were comparatively analyzed, determining the rock failure process and the microscopic failure types at compression-density stages, elastic stages, and destruction stages. The results show that the properties of the filled specimens improved, the failure process was mitigated, and the final failure stage was dominated by tension signals, accounting for over 60% of the total. The filling effect was better than 1.5–2.0 mm when the fracture width was 0.7–1.0 mm. The study deeply reveals the evolutionary process of compressive failure of the two types of rocks under different fracture widths, and by correlating the acoustic emission parameters with the stress–strain process, it provides a theoretical basis for repairing rock fractures using microbial engineering technology and offers experimental evidence and possible directions for the improvement and optimization of MICP technology.

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Estimation of mode I fracture toughness of rocks exposed to different environmental conditions using simple and linear multiple regression

Özdemir,

Eren Sarici

2024

Mech Time-Depend Mater

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Mode I fracture toughness (Kıc) is a critical parameter in rock mechanics that is essential for understanding how rocks behave under tensile loading and crucial for applications ranging from safety assessments to structural design in geotechnical engineering. This study comprehensively investigates the influence of various environmental conditions (dry, saturated, frozen, thermal shock and thermal aging) on the physico-mechanical properties and Kıc of rocks. The primary novelty of this study lies in its comprehensive modeling approach under diverse environmental conditions, providing a nuanced understanding of factors influencing rock fracture toughness. By extending analysis to less-studied conditions such as freezing and thermal shock cycles, the study enhances the predictive capacity of fracture toughness models in practical geotechnical applications. Physico-mechanical properties, including uniaxial compressive strength, point load strength, Brazilian tensile strength (BT), Schmidt hardness, and ultrasonic wave velocity were evaluated across different environmental scenarios. Simple and linear multiple regression models were developed using these properties to predict Kıc. Notably, BT emerged as a significant predictor in the simple regression analyzes. Ten linear multiple regression models were formulated using SPSS 20, combining mechanical tests (UCS, BT, PL) with non-destructive testing methods (Vp, Vs, SH), demonstrating robust predictive capabilities with R2 values exceeding 0.95. Performance metrics (mean absolute error, mean absolute percentage error, root mean square error) were used to verify the accuracy of the model.

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Influences of notch width and notch-tip angle on the fracture toughness measurement using the semi-circular bend (SCB) specimen

Cited by 16 publications

References 52 publications

Numerical investigation on the crack resistance curve of thermally treated quartz‐diorite rock under mixed mode I + II loading

Numerical investigation on the crack resistance curve of thermally treated quartz‐diorite rock under mixed mode I + II loading

Experimental Study on Acoustic Emission Characteristics of Uniaxial Compression of MICP-Filled Sandstone

Estimation of mode I fracture toughness of rocks exposed to different environmental conditions using simple and linear multiple regression

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