Article
Geochemistry & Geophysics
Michael J. Braunagel, W. Ashley Griffith
Summary: Fracture initiation and growth in rocks is a complex process that is influenced by grain-scale heterogeneity and changing stress states under dynamic loading conditions. Both crystalline and granular rocks exhibit similar fracture behaviors as engineered materials, such as rate-dependent fracture initiation toughness and a relationship between propagation toughness and crack velocity. However, the measured propagation toughness in rocks is higher than quasi-static values at lower crack velocities. Additionally, mixed mode crack propagation is fundamentally different between granite and sandstone due to grain scale controls on the fracture process.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Engineering, Mechanical
Sana Zafar, Ahmadreza Hedayat, Omid Moradian
Summary: This study conducted laboratory-scale experiments and data analysis on rock specimens to understand the evolution of tensile and shear cracking under different stress levels. By using acoustic emission and digital image correlation techniques, we were able to track the changes in the source mechanisms of the cracks and identify the correlation between the cracking mechanisms at different stages of the cracks.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Engineering, Geological
Erick Rogenes, Marcio Muniz de Farias, Leandro Lima Rasmussen
Summary: This paper presents a numerical model for representing the fracture process in hard rocks, validated through calibration with laboratory test results for Creighton granite. A sensitivity study led to the proposal of a calibration methodology to facilitate future use of the CVBM.
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
(2022)
Article
Engineering, Mechanical
Guang Liu, Ming Cai, Huayan Yao, Guan Rong, Zhenhua Zhang, Yanqiao Wang
Summary: This study proposes an empirical model based on microstructure to describe the relationship between the strength of rocks and their micro-property parameters. By analyzing the heterogeneity index of granular rocks, it is verified that the proposed model can better predict the strength of rocks and also predict the crack initiation and damage stresses of rocks.
ENGINEERING FAILURE ANALYSIS
(2022)
Article
Energy & Fuels
Xianwei Dai, Zhongwei Huang, Wenchao Zou, Xiaoguang Wu, Huaizhong Shi
Summary: This study examines the effects of PDC cutter indentation on rocks through a series of experiments. The results show that back rake angle significantly influences the rock cutting process and the position of brittle failure, with plastic failure dominating at angles below 20 degrees and chipping occurring at angles above 40 degrees.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Geological
Xiao-Ping Zhou, Jian-Zhi Zhang
Summary: This paper experimentally evaluates stress-induced damage progression and acoustic emission in granite and sandstone based on continuous acousto-optic-mechanical observations. Mechanistic correlations among the AOM characteristics in the two rock types are also investigated in detail. The results show significant differences in the AE event rate characteristics and acoustic-optical evidences for process zone nucleation between granite and sandstone.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Physics, Fluids & Plasmas
J. S. Langer
Summary: This paper attempts to construct a first-principles theory of the fracture toughness of crystalline solids based on the thermodynamic dislocation theory. The analysis results show that the theory's predictions quantitatively agree with experimental data, including both brittle and ductile fracture under various conditions.
Article
Materials Science, Multidisciplinary
Fengshi Li, Hewei Zhao, Xiaoyi Sun, Yonghai Yue, Zhongchang Wang, Lin Guo
Summary: In this study, a super-strong and flexible fiber was successfully prepared by introducing a crystalline GO and amorphous ZrO2 superstructure, which is analogous to a naturally ordered microstructure in nacre. The fiber showed excellent combination of high strength and toughness. The findings demonstrate that the crystalline-amorphous dual-phase strategy can serve as an economical and environment-friendly method to prepare GO-based fibers with high performance.
Article
Geosciences, Multidisciplinary
Lei Wu, Guoqing Chen, Jingfang Xing, Zhiyi Lin
Summary: This paper investigates the brittle cataclastic process of fault rocks, focusing on the structural evolution and mechanical behavior. A large-displacement direct shear model is proposed to simulate the process. The results indicate that the reduction in friction coefficient is caused by the crushing and rounding of rock fragments.
JOURNAL OF STRUCTURAL GEOLOGY
(2022)
Article
Polymer Science
Xintian Xie, Liang Wu, Huai Sun, Xuzhou Yan, Xinyuan Zhu
Summary: In this study, coarse-grained molecular dynamics simulation is used to investigate the thermodynamics and phase behavior of [2]catenane. The mechanical bond in [2]catenane not only destabilizes the packing between molecular rings but also provides additional internal degrees of freedom. The [2]catenane molecule undergoes a conformation transition from free-rolling to cross-stacking with respect to density increase, and exhibits a smectic layering structure with high free volume, showing cubatic ordering due to the interpenetration of macrocycles.
Article
Geochemistry & Geophysics
Auriol S. P. Rae, Thomas Kenkmann, Vivek Padmanabha, Michael H. Poelchau, Frank Schaefer, Matthias A. Doerfler, Louis Mueller
Summary: Brittle deformation at high strain rates can cause fragmentation and pulverisation of rocks. The characteristic strain rates for rate-dependent brittle failure range from 150 to 300 s(-1) in the investigated lithologies. There is an empirical inverse power-law relationship between fragment size and strain rate, while fragment shape is independent of strain rate.
Article
Engineering, Geological
Gabriel Walton, Steven Gaines, Leandro R. Alejano
Summary: This study examined the potential use of continuous-failure-state testing to constrain the residual strength envelope of rocks, finding that the data obtained from this method were consistent with traditional residual strength data. The primary factor limiting accurate characterization of residual strength for a given rock type is the variety of specimens available, rather than the amount of data for a single specimen. Therefore, continuous-failure-state testing is recommended only when the number of specimens available for testing is very limited.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2021)
Article
Geochemistry & Geophysics
Christopher Harbord, Nicolas Brantut, David Wallis
Summary: The study investigates the influence of grain size on the rheological behavior of calcite aggregates in the semi-brittle regime. Compressive triaxial deformation tests are conducted on different rocks with varying grain sizes. The results show that both strength and hardening rate increase with decreasing grain size, and flow stress scales with the inverse of grain size. Microstructural observations reveal high twin densities in deformed samples, which increase with stress. The effect of twins on dislocation accumulation and hardening rate is likely smaller than the effect of grain size.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Engineering, Mechanical
Peng Li, Meifeng Cai, Yubing Gao, Peitao Wang, Shengjun Miao, Yu Wang
Summary: The presence of cross joints and the change in included angles significantly affect the strength and deformation properties of brittle jointed rocks. Observations in mechanics, acoustics, and optics provide a comprehensive understanding of the fracture evolution and failure behavior around openings.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Engineering, Mechanical
X. F. Li, H. B. Li, G. K. Zhang, M. H. Ju, Jian Zhao
Summary: This study proposes a novel three-dimensional multiscale method to investigate the dynamic behaviors and microfracturing in granitic rocks, involving reproducing heterogeneity in mineral components and using particle filling in subgrains to allow for transgranular fracturing. The reasonability and accuracy of the method are verified by comparing with experimental results, and the underlying mechanism of grain-scale fracturing leading to fractal fracture surfaces, pervasively grain pulverization and deflection/penetration cracking model are discussed. The appearance of multicracks activation and the transition from intergranular fracturing to transgranular fracturing is identified as the underlying mechanism of rate dependency for granitic rocks.
INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
(2021)
Article
Engineering, Geological
Amit Kumar Shrivastava, K. Seshagiri Rao
ROCK MECHANICS AND ROCK ENGINEERING
(2018)
Article
Engineering, Geological
Aditya Singh, Chandan Kumar, L. Gopi Kannan, K. Seshagiri Rao, Ramanathan Ayothiraman
ENGINEERING GEOLOGY
(2018)
Article
Engineering, Geological
S. M. Mahdi Niktabar, K. Seshagiri Rao, Amit Kumar Shrivastava
GEOTECHNICAL TESTING JOURNAL
(2018)
Article
Engineering, Geological
Aditya Singh, Chandan Kumar, L. Gopi Kannan, K. Seshagiri Rao, Ramanathan Ayothiraman
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2018)
Article
Engineering, Civil
Akx Malik, Tanusree Chakraborty, K. Seshagiri Rao
THIN-WALLED STRUCTURES
(2018)
Article
Engineering, Civil
Swapnil Mishra, K. S. Rao, N. K. Gupta, Ankesh Kumar
THIN-WALLED STRUCTURES
(2018)
Article
Engineering, Geological
Ketan Arora, Tanusree Chakraborty, K. Seshagiri Rao
ROCK MECHANICS AND ROCK ENGINEERING
(2019)
Article
Geosciences, Multidisciplinary
Aditya Singh, K. Seshagiri Rao, Amanathan Ayothiraman
ARABIAN JOURNAL OF GEOSCIENCES
(2019)
Proceedings Paper
Energy & Fuels
A. Praveen, G. Lakshmi Narayana Rao, B. Balakrishna, K. Seshagiri Rao
RENEWABLE ENERGY SOURCES AND TECHNOLOGIES
(2019)
Article
Engineering, Geological
Aditya Singh, K. Seshagiri Rao, Ramanathan Ayothiraman
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2019)
Article
Engineering, Geological
Aditya Singh, K. Seshagiri Rao, Ramanathan Ayothiraman
INDIAN GEOTECHNICAL JOURNAL
(2019)
Proceedings Paper
Materials Science, Multidisciplinary
Aditya Singh, K. Seshagiri Rao, Ramanathan Ayothiraman
PLASTICITY AND IMPACT MECHANICS
(2017)
Article
Engineering, Geological
S. M. Mahdi Niktabar, K. Seshagiri Rao, Amit Kumar Shrivastava
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2017)
Proceedings Paper
Mining & Mineral Processing
A. P. Singh, T. Bhandari, R. Ayothiraman, K. Seshagiri Rao
ISRM EUROPEAN ROCK MECHANICS SYMPOSIUM EUROCK 2017
(2017)
Proceedings Paper
Mining & Mineral Processing
Tarun Singh, Ashwani Jain, K. S. Rao
ISRM EUROPEAN ROCK MECHANICS SYMPOSIUM EUROCK 2017
(2017)
