Article
Engineering, Civil
Zhitao Zhang, Weijie Gu
Summary: The propagation process of 3-D internal cracks under semi-circular bending was investigated through numerical simulations based on the finite element method. The results show that the crack propagation characteristics and fracture morphology are different for the symmetrical and asymmetrical loading models. In the symmetrical loading model, the internal crack propagates in-plane, causing specimen failure. In the asymmetrical loading model, the internal crack propagates in a wing shape, resulting in specimen fracture into two parts. The crack propagation path is influenced by factors such as loading mode and loading span.
PERIODICA POLYTECHNICA-CIVIL ENGINEERING
(2022)
Article
Chemistry, Physical
Taoying Liu, Mengyuan Cui, Qing Li, Shan Yang, Zhanfu Yu, Yeshan Sheng, Ping Cao, Keping Zhou
Summary: Multiple compression tests were conducted on rock-like samples with different crack geometries to investigate strength properties and crack propagation behavior considering multi-crack interactions. The study proposed a mechanical model of the multi-crack rock mass to investigate fracture and damage evolution traits based on the exploration of compression-shear wing crack initiation and propagation. The comparison between theory and experimental results revealed the variation of peak strength with fissure inclination angles and density of fissure distribution.
Article
Geosciences, Multidisciplinary
Yiwei Gao, Xuhua Ren, Jixun Zhang, Tao Xu, Hongyan Gu, Xun Xiang, Zhenyang Xin
Summary: Numerical simulation of rock fracture mechanics is a challenging and important research area in rock mechanics. In this study, a new numerical simulation method called RGIMP is proposed to simulate the brittle fracture process of rocks and display the resulting cracks. The accuracy of the method is verified through numerical simulations of different specimens. The research results have significant implications for the application of smooth particle dynamics methods in rock mechanics engineering and the understanding of rock fracture mechanisms.
Article
Energy & Fuels
Jinwei Fu, Joseph F. Labuz, Mengdi Guo, Huixiang Cheng, Rongbin Hou
Summary: A new transparent resin material with a high compression-tension strength ratio has been developed, which can simulate various engineering rocks. Uniaxial and biaxial hydraulic fracturing experiments were conducted to analyze the effect of water injection on the mechanical properties of the specimens. The results were validated through numerical simulations, indicating the feasibility of the proposed method.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Geological
Wenchen Fan, Hui Yang, Xueliang Jiang, Ping Cao
Summary: The study investigates the failure mechanism of rock masses with overlapped fissures by conducting uniaxial compressive tests and numerical studies on Portland cement samples containing folded flaws of different dip angles and undulation angles. Results show that the deformational curves of specimens containing folded flaws exhibit two patterns, and five different failure modes were observed. The folded flaw can still resist shear stress after crack coalescence, contributing to the residual peak strength in stress-displacement curves. The findings provide a better understanding of the failure mechanism of rock masses with folded fractures.
ENGINEERING GEOLOGY
(2021)
Article
Engineering, Geological
C. Wei, B. Zhang, W. Zhu, S. Wang, J. Li, L. Yang, C. Lin
Summary: The study shows that applying fluid pressure in the fracture can accelerate wing crack propagation while inhibiting the formation of secondary cracks, leading to tensile failure of specimens. Fluid pressure in the fracture promotes the initiation and propagation of wing cracks, but also gradually decreases the initiation stress and peak strength of the specimens.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Engineering, Geological
Martina Pressacco, Jari J. J. Kangas, Timo Saksala
Summary: This study numerically evaluates the effects of microwave heating on the mechanical properties of hard rock, showing that microwave heating can significantly reduce the compressive and tensile strength of the rock.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Mechanics
Shan Guo, Quan Zhang, Manchao He, Jiong Wang, Jianning Liu, Can Ming, Longji Guo, Lanxiang Fan
Summary: This article introduces the technology of Instantaneous Expansion with a Single Fracture (IESF), which uses expansion gas induced by special slitting agents to produce a single fracture in the selected direction. Numerical simulations and field experiments have shown that this technology has advantages such as a high crack rate, low induced vibration, high-level safety, and rapid rock-breaking response, providing a new method for directional rock-breaking.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Multidisciplinary Sciences
Kesheng Li, Zhen Zhao, Depeng Ma, Chuanxiao Liu, Jinpeng Zhang
Summary: This study investigates the influence of single fracture dip on the mechanical properties and acoustic emission parameters of rock-like materials through experiments and numerical simulations. The results indicate that as the crack dip angle increases, the rock material's peak strength will be affected, with the lowest strength at a dip angle of 45 degrees. The specimens with prefabricated 45 degrees inclined fractures show the highest degree of deterioration, releasing approximately 1/10 of the energy of other rock-like materials.
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Guodong Li, Changlong Li, Jianxing Liao, Hong Wang
Summary: This study proposes an equivalent fracture model that incorporates unsaturated seepage and fracture deformation to predict tunnel water inflow in karst regions. The model's effectiveness is verified through its application to predict water inflow in the Jianxing Tunnel in Guizhou Province. The results indicate that the inflow rate in a fractured network reaches a steady state faster than that in a non-fractured network.
Article
Computer Science, Interdisciplinary Applications
Luming Zhou, Shu Zhu, Zhende Zhu
Summary: This paper proposes an ordinary state-based peridynamic (OS-PD) model based on the Cosserat continuum to predict the propagation and coalescence of rock cracks. Compared with the classical OS-PD model, the pairwise moment between two material points is also considered in the proposed Cosserat ordinary state-based peridynamic (COS-PD) model. The rotational stiffness and rotation angle are introduced to characterize the microdeformation and microstructure of rock, and the expression of rotational stiffness coefficient is derived. Three numerical cases are presented to compare the performance of OS-PD model and COS-PD model, and the effect of rotational stiffness on crack growth is investigated. The results show that the introduction of pairwise moment accelerates the rock failure process, and the crack propagation type and coalescence mode are more inclined to shear failure with the increase of rotation stiffness coefficient. Compared with experimental results, it is found that the COS-PD model can extend the classical OS-PD model and better capture the evolution process of the rock crack.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Engineering, Mechanical
Mohammad Khalili, Ahmad Fahimifar, Hooman Shobeiri
Summary: This paper investigates the effect of bedding planes on the failure and crack propagation mechanism in rock-like materials. The laboratory studies conducted on concrete specimens reveal that bedding planes generally affect the crack propagation mechanism and change the fracture mode. The anisotropic specimens exhibit smaller strength and fracture parameters compared to the isotropic ones, and the fracture mode changes from pure opening mode to mixed modes. Furthermore, the parameters exhibit different trends with increasing bedding angles.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Geosciences, Multidisciplinary
Shaorui Sun, Jin Wang, Huilin Le, Haotian Fan, Wuchao Wang
Summary: This study investigates the influence of confining stress and inclination angle on cracking behavior and failure mechanism in jointed rock masses. Tensile failure and tensile shear failure are observed, with equal frequency. Nine crack modes are summarized, with mode 8 being the most special. Compressive strength and internal friction are found to be the smallest in samples with a inclination angle of 60 degrees. The compressive strength decreases with increasing inclination angle from 0 to 60 degrees, but increases from 60 to 90 degrees. Numerical tests confirm the impact of the width-to-length ratio of opening flaws on compressive strength and opening fracture intensity factor K-I.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Engineering, Mechanical
Yong Niu, Jin-Guo Wang, Xing-Kai Wang, Yun-Jin Hu, Jian-Zhi Zhang, Ran-Ran Zhang, Zhi-Jun Hu
Summary: In this study, the extended non-ordinary state-based peridynamics (NOSB-PD) theory is used to simulate the fracture process of rocks with pre-existing flaws. The maximum tensile stress criterion and the Mohr-Coulomb criterion are implemented to determine the types of fracture. The effects of inclination angles and ligament angles on crack initiation and coalescence modes are investigated, and the numerical results are in good agreement with previous experimental results. The fracture mechanism of flawed rocks is revealed based on the distribution characteristics of stress fields obtained by the extended NOSB-PD theory.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Engineering, Geological
Chao Wei, Shucai Li, Bo Zhang, Yang Song, Yu Zhang, Xianggang Wang
Summary: This study investigates the influence of fluid pressure and lateral pressure on crack propagation, rock bridge failure mechanism, and rock failure modes through experimental analysis. The results show that under uniaxial compression, fluid pressure and lateral pressure change the failure forms and strength characteristics of rock bridges, promoting the growth of tensile cracks and causing more obvious brittle failure characteristics in the specimen.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Mechanics
Xiaolong Liu, Kelian Luo, Pengcheng Gao, Tao Cong, Xi Wang, Wenjing Wang
Summary: This paper investigates the formation mechanisms of the zig-zag crack region on the shattered rim of railway wheels. The zig-zag crack region, identified as a typical region for crack propagation in rolling contact fatigue behavior, was observed using scanning electron microscopy and transmission electron microscopy. The formation of the zig-zag morphology is attributed to the periodic deflection of the propagation path relative to the initial propagation plane, caused by the limited plastic deformation zone at the crack tip. Grain refinement and secondary cracks in the zig-zag crack region are a result of the large compressive and shear stresses induced by rolling contact loading.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Anastasia Iziumova, Aleksei Vshivkov, Ivan Panteleev, Virginia Mubassarova, Oleg Plekhov, Denis Davydov
Summary: The aim of this study was to investigate the correlation between structural, acoustic emission, and thermal characteristics of fatigue crack growth in titanium alloys. Cluster analysis of the acoustic emission signals revealed two different types of signals observed during the fatigue crack development. It was experimentally demonstrated that the stored energy tends to reach an asymptotic value at the final stage of fatigue crack growth and this is correlated with the twinning process intensification in titanium alloy Ti Grade 2. A correlation was assumed between the stages of change in heat flux, the cumulative energy of the first cluster of acoustic emission signals, and the crack length.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
M. Vieira de Carvalho, I. A. Rodrigues Lopes, F. M. Andrade Pires
Summary: This study investigates the numerical challenges of fracture mechanics models within implicit quasi-static frameworks and proposes an instability criterion. The ratio of cohesive to internal power is identified as a crucial factor. Two strategies for handling fracture problems with instabilities are discussed and a comparative assessment is performed. The study also examines more complex material responses, including transformation-induced plasticity effects.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Thomas Duminy, Aurelien Doitrand, Sylvain Meille
Summary: This study conducted in situ wedge splitting tests on millimeter-size PMMA samples and proposed a method to determine the material tensile strength and critical energy release rate using digital image correlation and a full finite element implementation of the coupled criterion.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Xin Chang, Xingyi Wang, Chunhe Yang, Yintong Guo, Yanghui Wan
Summary: The influence of cyclic thermal shock and high-temperature acid etching on the Mode I fracture of shale was investigated in this study. It was found that cyclic thermal shock severely degrades the strength and fracture toughness of shale, while high-temperature acid etching treatment improves the fracture toughness. These findings are valuable for optimizing process parameters to reduce initiation pressure in deep shale formations.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Liaojun Yao, Mingyue Chuai, Zhangming Lyu, Xiangming Chen, Licheng Guo, R. C. Alderliesten
Summary: Methods based on fracture mechanics have been widely used in fatigue delamination growth (FDG) characterization of composite laminates. This study proposes appropriate similitude parameters to represent FDG behavior with different R-ratios.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Zesheng Zang, Zhonghui Li, Yue Niu, Shan Yin
Summary: This study conducted experiments and recorded signals to investigate the fracture behavior and damage evolution characteristics of coal samples. The results showed that as loading proceeds, the stress, electric potential (EP), and acoustic emission (AE) values increase, and EP and AE signals are excited when stress drops. The fracture behavior of coal samples is altered by flaw inclination, and the destruction mode becomes increasingly complicated. The damage evolution characteristics of coal samples can be evaluated and analyzed by defining the coefficient of variation (CV value) of EP and the b value of AE.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Clotilde Berdin, Nathalie Prud'homme
Summary: In this study, zirconia layers with different fractions of tetragonal phase and thicknesses were tested for multi-cracking behavior. Cracks perpendicular to the tensile direction were observed, showing a blunting effect into the substrate. The ratio of crack spacing at saturation to layer thickness decreased as the layer thickness increased. Unit cell modeling was used to establish a relationship between crack spacing and layer strength, which fell within the bounds of Hu and Evans model and was found to be insensitive to the tetragonal zirconia fraction.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Huadong Zhang, Weichen Kong, Y. H. Liu, Yuh J. Chao
Summary: Williams' series expansion crack tip solution in linear elasticity is modified to include a uniform crack face pressure. Practical methods to calculate T-stress from near crack tip stresses are outlined. The analytical results are consistent with numerical results.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Jiahao Kong, Haoyue Han, Tao Wang, Guangyan Huang, Zhuo Zhuang
Summary: This paper introduces a phase-field model for polymer foam materials by combining the phase-field method with the crushable foam model. The model is calibrated using experimental data and successfully simulates the fracture processes of polyurethane under different loading conditions. The study is important for the engineering applications of polymer foam materials.
ENGINEERING FRACTURE MECHANICS
(2024)
