Showing papers on "Fracture (geology) published in 2022"
TL;DR: Wang et al. as discussed by the authors used three-dimensional dynamic scanning technology to reconstruct the fracture morphology of disced cores extracted from Songke-2 as well as part of the Chinese Continental Scientific Drilling Project.
74 citations
TL;DR: In this paper, a CO2 foam fracturing fracture propagation model with temperature-pressure-phase coupling is established, and the results of this model are compared with the field measured data, KGD model and EFRAC-3D model to verify the model.
69 citations
TL;DR: In this article, a new method for estimating crack-initiation stresses is proposed based on the evolution of T2 curve and fractal dimension DT of the total pores with stress.
68 citations
TL;DR: In this paper , a series of microscopic tests and a thermal damage simulation were combined to evaluate the changes in the internal structure of coal caused by liquid nitrogen (LN 2 ) cooling, firstly, Brazilian splitting tests were carried out on the bedding coal, and influences of cryogenic cooling fracturing and bedding orientation on mechanical properties and fracture morphology of coal were analyzed.
66 citations
TL;DR: In this article, the authors proposed a thermo-hydro-mechanical coupling model considering the deformation of fractal fractures, which is regarded as a thin elastic layer existed in the bedrock, whoes deformation depends to the bedrock and its own mechanical properties.
60 citations
TL;DR: In this paper , the authors proposed a thermo-hydro-mechanical coupling model considering the deformation of fractal fractures, which is regarded as a thin elastic layer existed in the bedrock, whoes deformation depends to the bedrock and its own mechanical properties.
59 citations
TL;DR: In this article , a CO 2 foam fracturing fracture propagation model with temperature-pressure phase coupling is established, and the results of this model with the field measured data, KGD model and EFRAC-3D model are compared.
56 citations
TL;DR: In this paper , a multistage constant-amplitude-cyclic (MCAC) loading experiments were conducted on interbedded skarns to investigate and characterize fatigue mechanical behavior of the tested rock.
53 citations
TL;DR: In this article , the fracture mechanics parameters of new concrete composites based on quaternary blended cements (QBC) have been investigated and a composition of the two most commonly used mineral additives, i.e., fly ash (FA) and silica fume (SF), in combination with nanosilica (nS), has been proposed as a partial replacement for ordinary Portland cement (OPC) binder.
Abstract: This study presents test results and in-depth discussion regarding the measurement of the fracture mechanics parameters of new concrete composites based on quaternary blended cements (QBC). A composition of the two most commonly used mineral additives, i.e., fly ash (FA) and silica fume (SF), in combination with nanosilica (nS), has been proposed as a partial replacement for ordinary Portland cement (OPC) binder. Four series of concrete were made, one of which was the reference concrete (REF) and the remaining three were QBC. During the research, the main mechanical parameters of compressive strength (fcm) and splitting tensile strength (fctm), as well as fracture mechanics parameters and the critical stress intensity factor KIcS, along with critical crack-tip opening displacements (CTODc) were investigated. Based on the tests, it was found that the total addition of siliceous materials, i.e., SF + nS without FA, increases the strength and fracture parameters of concrete by approximately 40%. On the other hand, supplementing the composition of the binder with SF and nS with 5% of FA additive causes an increase in all mechanical parameters by approximately 10%, whereas an increase by another 10% in the FA content in the concrete mix causes a significant decrease in all the analyzed factors by 10%, compared to the composite with the addition of silica modifiers only.
53 citations
TL;DR: In this article , the fracture toughness of quaternary binder concretes has been evaluated using the Digital Image Correlation (DIC) measurements and visual analysis of cracks propagation.
53 citations
TL;DR: In this article , the influence of polyethylene fiber and water-binder ratio on the fracture properties of high-tough geopolymer is studied, and the results indicated that the fiber factor (product of fiber length-diameter ratio and volume fraction) for PFRG can describe the comprehensive effect of fiber lengths and content.
TL;DR: In this article , a physics-informed variational formulation of DeepONet (V-DeepONet) is proposed for brittle fracture analysis, which is trained to map the initial configuration of the defect to the relevant fields of interests (e.g., damage and displacements).
TL;DR: In this article , the authors focus on two promising approaches: phase-field (PF) and peridynamic (PD) models applied to this class of problems and evaluate them in terms of their computational effort and predictive capabilities.
Abstract: Abstract Computational modeling of the initiation and propagation of complex fracture is central to the discipline of engineering fracture mechanics. This review focuses on two promising approaches: phase-field (PF) and peridynamic (PD) models applied to this class of problems. The basic concepts consisting of constitutive models, failure criteria, discretization schemes, and numerical analysis are briefly summarized for both models. Validation against experimental data is essential for all computational methods to demonstrate predictive accuracy. To that end, the Sandia Fracture Challenge and similar experimental data sets where both models could be benchmarked against are showcased. Emphasis is made to converge on common metrics for the evaluation of these two fracture modeling approaches. Both PD and PF models are assessed in terms of their computational effort and predictive capabilities, with their relative advantages and challenges are summarized.
TL;DR: In this paper, a finite volume method is used to discretize the mass and energy conservative equations, and all the connections between control volumes including two types of fracture-matrix (f-m), three types of fractures fracture-fracture (f -f), and one type of matrix-matrices (m-m) connections are constructed, and corresponding transmissibility formulas of mass and heat transfer in finite-volume discrete schemes for these connections are given.
TL;DR: In this article , the authors used 3D particle flow code to investigate the crack propagation mechanisms under uniaxial compression and found that the average peak strength increases with the growth of non-penetrating flaw angle and reduced by 21.8% for 0°, 16.0% for 30°, 13.0%, 4.7% for 60°, and 0.5% for 90° compared with the peak strength of the intact specimen.
TL;DR: In this article, the authors provide a critical review of the proppant settling in hydraulic fractures, with an emphasis on the experimental studies published in the past several decades. But, a gap still exists between experimental studies and the application of the experimental findings to numerical simulations of hydraulic fracturing.
TL;DR: In this article , two geometric parameters, namely, fractal dimension and fracture entropy, are proposed to determine the spatial and temporal states of rock mass fractures caused by mining, and a spatiotemporal model is created to examine the spatial patterns of hot and cold spots of the fractures based on a Geographic Information System (GIS).
Abstract: Fractures caused by mining are the main form of water inrush disaster. However, the temporal and spatial development characteristics of fractures of the rock mass due to mining are not clearly understood at present. In this paper, two geometric parameters, namely, fractal dimension and fracture entropy, are proposed to determine the spatial and temporal states of rock mass fractures caused by mining. The spatial and temporal structure characteristics of fractures in the rock mass due to mining are simulated with physical scale model testing based on digital image processing technology. A spatiotemporal model is created to examine the spatial and temporal patterns of hot and cold spots of the fractures based on a Geographic Information System (GIS). Results indicate that the fractal dimensions and entropy of the fractures network in the rock mass increase and decrease with the progression of mining, respectively, which can be examined in three stages. When the fractal dimension of the fractures in rock mass rapidly increases, the conductive fracture zone has a saddle shape. The fracture entropy of fracture has periodic characteristics in the advancing direction of the panel, which reflects the characteristics of periodic weighting. The fractal dimension and fracture entropy of fractures of the rock mass increase with time, and the rock mass system undergoes a process of increasing entropy. When the fractal dimension and fracture entropy of the fractures increase, the spatiotemporal state of fractures in rock mass caused by mining is initiated. When the fractal dimension and fracture entropy of the fractures decrease, the spatiotemporal state of fractures in rock mass is closed.
TL;DR: In this article , the authors present an overview of the theories and computer implementation aspects of phase field models (PFM) of fracture, which can elegantly simulate complicated fracture processes including fracture initiation, propagation, coalescence, and branching.
TL;DR: In this paper, the authors investigated the relationship between fracture behavior and pumping parameters (pressure and injection rate) by performing laboratory fracturing experiments under constant pressure injection mode (Pcon = 17, 19, and 21 MPa), and they found that fracture initiation, arrest, stable propagation, and unstable propagation are closely correlated to the variations of pumping pressure, injection rate, and pressure decay rate.
TL;DR: In this paper , a new test configuration was used to investigate the full range of mixed-mode I/II fracture behavior of asphalt mixtures using a Short Beam Bending (SBB) specimen with a vertical edge crack, which was subjected to an asymmetric three-point bending load.
TL;DR: In this article, a new test configuration was used to investigate the full range of mixed-mode I/II fracture behavior of asphalt mixtures using a Short Beam Bending (SBB) specimen with a vertical edge crack, which was subjected to an asymmetric three-point bending load.
TL;DR: In this article , a cohesive/volumetric modeling technique based on a diffuse interface fracture approach is proposed to in-depth investigate the debonding mechanisms in FRP-plated RC beams and subsequently validated through experimental results.
TL;DR: In this article , the fracture characteristics of high-strength hydraulic concrete subjected to different FT damage (0, 100, 200, 300, 400 FT cycles) are studied by experimental analysis and discrete element method (DEM) simulation.
TL;DR: In this paper , the crack-tip blunting effect from FPZ width and length is analyzed for quasi-brittle fracture of heterogeneous solids, showing that FPZW at the peak fracture load bridges the gap between the fracture toughness KIC and tensile strength ft.
TL;DR: In this paper , the mode I tensile fracture toughness tests at different temperatures (253.15-343.15 K) and loading rates (2-500 mm/min) were conducted on the newly designed circumferentially notched cylinder sample with different initial crack sizes (4.5 and 6.5 mm) for hydroxyl-terminated polybutadiene (HTPB) propellant.
Abstract: To comprehensively understand the fracture properties of solid propellants, the mode I tensile fracture toughness tests at different temperatures (253.15–343.15 K) and loading rates (2–500 mm/min) were conducted on the newly designed circumferentially notched cylinder sample with different initial crack sizes (4.5 and 6.5 mm) for hydroxyl-terminated polybutadiene (HTPB) propellant. Test results reveal that the shape of the tensile fracture stress-strain curves was not significantly influenced by temperature, loading rate and the initial crack size. Higher loading rate and lower temperature can lead to a rise in the tensile fracture toughness of HTPB propellant described by the stress intensity factor, however, continuously increasing loading rate cannot dramatically improve this fracture toughness beyond the rate of 250 mm/min. In addition, the fracture toughness is more sensitive to temperature. Furthermore, the variation of the initial crack size causes obvious changes in the fracture toughness with the coupled effects of low temperature and higher loading rates. At these test conditions, a higher tensile fracture toughness can be obtained with the shorter initial crack. For all the test conditions, there is a linear rise in the strain corresponding to the fracture toughness as temperature increases. Meanwhile, this strain increases with the shorter initial crack. Whereas, the effect of loading rate on this strain is complex. Based on the time-temperature superposition principle (TTSP), the master curves with a log-curvilinear form were constructed to predict the mode I tensile fracture toughness of the propellant at different initial crack sizes in a wide range of loading conditions.
TL;DR: In this paper , the fracture behavior of 3D-printed fiber-reinforced composites and steel specimens was determined and compared, and a series of experiments on semi-circular bending specimens was performed.
TL;DR: In this paper , the authors investigated the relationship between fracture behavior and pumping parameters (pressure and injection rate) by performing laboratory fracturing experiments under constant pressure injection mode (Pcon = 17, 19, and 21 MPa).
TL;DR: In this paper , the authors investigated the fracture evolution and instability warning predication for the fissure-contained hollow-cylinder granite exposed to multi-stage cyclic loads, and the influence of the hollow hole diameter on rock fracture was experimentally investigated in terms of deformation, hysteresis damping effects, energy conversion, and failure modes.