Quasi-static fracturing in double-flawed specimens under uniaxial loading: the role of strain rate

Zhang, Jian‐Zhi; Zhou, Xiaoping; Zhu, Jiayi; Xian, Chao; Wang, Yunteng

doi:10.1007/s10704-018-0277-8

Cited by 51 publications

(24 citation statements)

References 48 publications

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“…The crack initiation modes observed in the present experiments support this speculation. After the first crack initiation, the stress in specimen redistributes . Secondary stress distribution is controlled by geometric characteristics of both initiated macrocracks (tensile cracks) and preexisting flaws.…”

Section: Fracture Mechanism Of Sandstone With Non‐isometric Flawsmentioning

confidence: 99%

“…It is of fundamental significance to investigate the effects of preexisting flaws on mechanical and cracking behaviours of brittle rocks. Up to date, many experimental and theoretical studies were carried out to investigate mechanical and cracking behaviours in brittle flawed rocks or rock‐like specimens under uniaxial compression. For example, a comparative experimental study on the crack initiation, growth, and coalescence behaviours in gypsum specimens respectively containing open and closed flaws was conducted by Park and Bobet .…”

Section: Introductionmentioning

confidence: 99%

“…The present study aims at understanding how non‐isometric flaws interact to trigger a series of fracturing behaviours in flawed rocks. Hereafter, the term flaws refer to preexisting artificial fractures in rock specimens, while the newly generated fractures are described as cracks . To better capture the fracturing process, specimen behaviours are monitored by the combined acoustic emission (AE) and digital image correlation (DIC) techniques in real time.…”

Section: Introductionmentioning

confidence: 99%

“…[3][4][5] It is of fundamental significance to investigate the effects of preexisting flaws on mechanical and cracking behaviours of brittle rocks. Up to date, many experimental and theoretical studies 1,4,[6][7][8][9][10][11][12][13] were carried out to investigate mechanical and cracking behaviours in brittle flawed rocks or rock-like specimens under uniaxial compression. For example, a comparative experimental study on the crack initiation, growth, and Nomenclature: a, half flaw length; A, amplitude; AE, acoustic emission; AOM, acousto-optic-mechanical; b, half flaw spacing; DIC, digital image correlation; E s , elastic modulus; F (τ), inter-event time (IET) function; IET, inter-event time; N, number of AE events; NDT, nondestructive testing; PD, peridynamics; R l , flaw length ratio; RT, rise time; t, loading time; t f , failure-time; t i , time instant that the ith AE event occurs; u, horizontal displacement field; v, vertical displacement field; α, flaw inclination angle; σ UCS , peak stress; ε 1 , maximum principal strain field; ε 1c , peak axial strain; ε xy , maximum shear strain field; τ i , mean value of IETs; Δt i , time span for each group of N consecutive AE events coalescence behaviours in gypsum specimens respectively containing open and closed flaws was conducted by Park and Bobet.…”

Section: Introductionmentioning

confidence: 99%

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Progressive failure of brittle rocks with non‐isometric flaws: Insights from acousto‐optic‐mechanical (AOM) data

Zhang

Zhou

et al. 2019

Fatigue Fract Eng Mat Struct

124

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Uniaxial compression tests combined with nondestructive testing techniques are performed to explore the roles of non‐isometric flaws in crack developments in brittle rocks. The acoustic emission (AE) rate‐process theory is adopted to analyze fracture‐related AE event rate characteristics. The full‐field optical method is applied to detect cracking modes. Experimental results show that AE activity is quite active when the matrix microcracking is dominant, while after each macrocracking event, AE activity becomes inactive because of the stress release. Multiphysical data for each tested flaw configuration faithfully confirm the rupture progressivity. The larger the flaw length ratio, the lower the peak stress (also peak axial strain and elastic modulus), as well as the more progressive the cracking process. Moreover, ultimate failure is triggered by the shear fracturing from the relatively long flaw. The short flaw is conditionally involved in ultimate failure when the stress buildup effect dominates. Finally, the fracture mechanism of brittle rocks with non‐isometric flaws is revealed.

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Section: Fracture Mechanism Of Sandstone With Non‐isometric Flawsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Progressive failure of brittle rocks with non‐isometric flaws: Insights from acousto‐optic‐mechanical (AOM) data

Zhang

Zhou

et al. 2019

Fatigue Fract Eng Mat Struct

124

View full text Add to dashboard Cite

show abstract

“…Numerical methods can be classified into two categories: continuum‐based methods and discontinuum‐based methods. In terms of the continuum‐based methods, finite element method (FEM), finite difference method (FDM), boundary element method (BEM), extended finite element method (XFEM), phantom node method, strain softening elements, and specific meshfree methods, such as bond particle method (BPM), peridynamics (PD), smoothed particle hydrodynamics (SPH), and general particle dynamics (GPD), were developed to investigate interlayers and crack problems. In terms of the discontinuum‐based methods, distinct lattice spring model (DLSM), discrete element method (DEM), discontinuous deformation analysis (DDA), and numerical manifold method (NMM) were developed.…”

Section: Introductionmentioning

confidence: 99%

Simulation of cracking behaviours in interlayered rocks with flaws subjected to tension using a phase‐field method

Zhou

Jia

Berto

2019

Fatigue Fract Eng Mat Struct

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A phase‐field method (PFM) is used to investigate cracking behaviours, including crack initiation and propagation, in interlayered rocks with preexisting flaws subjected to tension. An example with a bi‐material plate with a centre flaw is used to validate the PFM. Then, numerical simulations of cracking behaviours in interlayered rocks with a single flaw and a cross‐flaw are carried out using PFM. Moreover, the load‐displacement responses are numerically investigated. The PFM numerical results show that the crack propagation trajectories and peak loads of rock specimens depend on the preexisting flaw configuration and the mechanical properties of the interlayers.

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Mechanical and Volumetric Fracturing Behaviour of Three-Dimensional Printing Rock-like Samples Under Dynamic Loading

2020

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Heterogeneous rock contains numerous pre-existing three-dimensional (3D) cracks, which control its mechanical and fracturing properties. Considerable effort has been devoted to studying the volumetric fracturing behaviour of rock under static loading conditions. Although rock masses are often subject to dynamic impacts such as earthquakes and blasting, the mechanical and volumetric fracturing behaviour of rock under dynamic loading is still poorly understood. In this paper, dynamic laboratory tests were performed on 3D-printed artificial rock samples with 3D embedded flaws created during three-dimensional printing (3DP), with the aim of studying the volumetric fracturing and mechanical properties of these samples under impact with high strain rate. The results show that the dynamic compressive strength and the tangent modulus decrease with an increasing number of flaws, but have very limited effects on the ratio of the fracture initiation stress of the first crack to the peak stress of the sample, the maximum axial strain of the sample and the volumetric fracturing behaviour of the sample. The tensile failure of a sample is caused by the continuous extension of wing cracks from the outer flaw tips. The mechanical and volumetric fracturing behaviour of samples with 3D embedded flaws are strain rate dependent. The tangential modulus and the ratio of the fracture initiation stress of the crack to the peak stress increase significantly when the loading type changes from static compression to dynamic compression. Under dynamic compression, wing cracks can continuously extend to the sample ends, whereas under static compression, wing cracks can intermittently extend only a limited distance. Moreover, the fracturing behaviour of 3D flaw differs from that of 2D flaws under dynamic loading. Under high strain rate loading, wing cracks generated at 3D flaw tips lead to splitting failure of the sample, while shear cracks formed at 2D flaw tips result predominant shear failure of the sample. The findings in this paper could facilitate a better understanding of rock failure subjected to dynamic loading conditions.

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Quasi-static fracturing in double-flawed specimens under uniaxial loading: the role of strain rate

Cited by 51 publications

References 48 publications

Progressive failure of brittle rocks with non‐isometric flaws: Insights from acousto‐optic‐mechanical (AOM) data

Progressive failure of brittle rocks with non‐isometric flaws: Insights from acousto‐optic‐mechanical (AOM) data

Simulation of cracking behaviours in interlayered rocks with flaws subjected to tension using a phase‐field method

Mechanical and Volumetric Fracturing Behaviour of Three-Dimensional Printing Rock-like Samples Under Dynamic Loading

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