Nanoscale deformation and crack processes of kaolinite under water impact using molecular dynamics simulations

Jia, Xiaotian; Hao, Youzhi; Li, Peichao; Zhang, Xin; Lu, Detang

doi:10.1016/j.clay.2021.106071

Cited by 11 publications

(7 citation statements)

References 27 publications

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“…To mimic the dynamic process of CO 2 injection, an external force F (kcal mol –1 Å –1 ) is applied downward onto each atom of the CO 2 molecules by varying different values in the LAMMPS command. In the simulation, the relationship between the applied force F and the injection pressure p can be derived as p = F n S N normalA where n refers to the total number of CO 2 molecules, N A is Avogadro’ s constant, which is equal to 6.02 × 10 23 , and S indicates the contact area between the CO 2 cluster and the surface of α-quartz. In simulation, the contact area S is just the surface area of the crack.…”

Section: Model and Methodologymentioning

confidence: 99%

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Crack Propagation during the Process of Carbon Dioxide Fracturing Based on Molecular Dynamics Simulations

2023

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Carbon dioxide (CO 2 ) fracturing is a powerful strategy for enhancement of oil recovery by creating more fractures in the formation so that it can efficiently improve the flow conditions of oils and gases underground. In the present study, we explore the whole process of crack propagation by injecting CO 2 molecules into the formation based on the molecular dynamics simulation. For the I-type crack of a rock sample, the details on the crack propagation are demonstrated, accompanied by the damage process near the crack tip. Next, the fracture toughness of the I-type crack is calculated according to the critical intensity factor and the energy balance equation, and the two results are in good agreement. Moreover, the CO 2 fracturing process is probed when the rock includes natural fractures, and all of the cracks are finally merged after propagation. The effects of CO 2 fracturing and hydraulic fracturing for breaking rocks are compared, and it is found that the first method is more conducive to the formation of multiple fractures and complicated crack surfaces. The reason is attributed to the expansion effect of the CO 2 molecules, and the diffusion coefficient and the radial distribution function are calculated. These findings are beneficial to depict the details of rock fracturing and provide some inspirations on inventing effective techniques of oil and gas development.

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Section: Model and Methodologymentioning

confidence: 99%

“…To mimic the dynamic process of CO 2 injection, an external force F (kcal mol −1 Å −1 ) is applied downward onto each atom of the CO 2 molecules by varying different values in the LAMMPS command. In the simulation, the relationship between the applied force F and the injection pressure p can be derived as32 …”

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confidence: 99%

Crack Propagation during the Process of Carbon Dioxide Fracturing Based on Molecular Dynamics Simulations

2023

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“…Zhang et al [ 9 ] analyzed three crack characterization parameters, crack width, depth and surface crack area rate, using iodine-starch staining tracer tests combined with digital image processing techniques. Jia et al [ 10 ] used molecular dynamics to simulate the deformation and cracking process of nanoclay particles under water impact, and found that the shedding of SiO 2 tetrahedral units led to cracks or holes, which also provided a molecular explanation for the microscopic mechanism and process of rupture of geotechnical materials. Wu et al [ 11 ] conducted evaporation tests on clay soils while monitoring shrinkage cracking and hygrothermal evolution, and found that the large difference in suction between the topsoil and the deep soil is an important reason for the uneven shrinkage of the soil at different depths.…”

Section: Introductionmentioning

confidence: 99%

Study on Cracking Law of Earthen Soil under Dry Shrinkage Condition

et al. 2022

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Earthen sites are easily eroded by the natural environment, resulting in a large number of micro cracks on the surface. In order to explore the internal relationship between environmental factors and the cracking law of soil sites, this paper carries out dry shrinkage tests of different soil layers at the Zhouqiao site, reconstructs the study on cracking law of earthen soil under dry shrinkage-conditioned microstructure of site soil at different depths based on electron microscope pictures and finite element method, and explores the influence of different moisture content on the cracking of soil samples at the site. The results show that under conditions of dry shrinkage, the thickness of the soil layer has the greatest influence on the cracking of site soil samples. Due to the internal water loss and shrinkage of the soil sample, the thinner the soil layer, the more often the soil layer cracks first. The crack rate of the soil sample with a thickness of 1 cm is nearly three times higher than that of the soil sample with a thickness of 5 cm. Through numerical simulation analysis, it is found that the evolution process of soil fractures at the Zhouqiao site is mainly divided into the formation stages of initial stress field, single main fracture, secondary fracture and fracture network. The formation time of the secondary fracture is longer than that of the initial stress field and single main fracture, and the cracking of the upper soil sample is more serious than that of the lower soil sample. Under conditions of dry shrinkage, the particle arrangement of the soil sample is relatively loose, and there are many cracks inside, which provides evaporation and infiltration channels for water, forming unrecoverable weak pores, and finally, the cracks start to sprout at the weak points. The research results provide some reference for the disease mechanism and safety analysis of earthen sites.

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“…They found that the Elastic modulus of the zigzag configuration with 15-36 Å radius is in the range of 230-300 GPA, and 300-340 GPa for the armchair arrangement with 21-46 Å radius 1 . Other researchers also determined that the HNTs are significantly flexible and can be bent 90 degrees without breaking 8 while a few investigations have been conducted to analyze the influence of geometry on stiffness 9 , strength 1,7,10,11 .…”

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confidence: 99%

Molecular Insight into Structural and Mechanical Properties of Halloysite Structure

Pebdani

2022

Preprint

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In this study, we simulated the rolling mechanism of Halloysite by molecular dynamics (MD) under different conditions. We have illustrated that the transformation from slab Halloysite to scroll shape depends on the initial geometry, dimension and proper selection of the interatomic potential. Also, the molecular simulation was conducted to determine the mechanical properties of Halloysite under different conditions. The results show that the Elastic modulus of the armchair Nano scroll was higher than the zigzag with similar dimensions and that Young's modulus of both arrangements decreases with increased radius. Moreover, with an increasing radius (>20 Å), Young's modulus of a Halloysite nano-scroll approaches that of the Halloysite slab configuration. Finally, the tensile strain of a Halloysite nanosheet was 0.08±0.04. The result of this study is a great help for understanding Halloysite, which can be used for designing nanocomposites.

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Nanoscale deformation and crack processes of kaolinite under water impact using molecular dynamics simulations

Cited by 11 publications

References 27 publications

Crack Propagation during the Process of Carbon Dioxide Fracturing Based on Molecular Dynamics Simulations

Crack Propagation during the Process of Carbon Dioxide Fracturing Based on Molecular Dynamics Simulations

Study on Cracking Law of Earthen Soil under Dry Shrinkage Condition

Molecular Insight into Structural and Mechanical Properties of Halloysite Structure

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