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Evolution mechanism and quantitative characterization of initial micro-cracks in marble under triaxial compression

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2024年第7期25卷 586-595页

作者： Zhiliang WANG Songyu LI Jianguo WANG Ao LI Weixiang WANG Chenchen FENG Jingjing FU school of civil engineering Hefei University of TechnologyHefei230009China school of Mechanics and civil engineering China University of Mining and TechnologyXuzhou221116China

The initial micro-cracks affect the evolution characteristics of macroscopic deformation and failure of rock but are often ignored in theoretical calculation,numerical simulation,and mechanical *** this study,we propose a quantitative analysis model to investigate the effects of initial micro-cracks on the evolution of marble deformation and *** relationship between the micro-crack propagation and the marble failure characteristics was comprehensively studied by combining theoretical analysis with a micro-computed tomography(micro-CT)scanning *** found that with the increase of confining pressure,the matrix elastic modulus of the marble first increased and then tended to be stable,while the micro-cracks increased *** sensitivity ranges of the marble sample matrix elastic modulus and micro-cracks to confining pressure were 0–30 MPa and 30–50 MPa,*** porosity and Poisson’s ratio decreased *** increasing proportion of internal micro-cracks led to an increase in the sample *** samples presented mainly shear failure under triaxial compression,and the failure angle decreased linearly with the increase of confining *** convergence direction of cracks decreased *** quantitative analysis model could accurately portray the relationship between the overall macroscopic deformation and the deviatoric stress of the samples at the compaction and the linear elastic stages,thus deepening the understanding of the stress–strain behavior of rocks.

关键词： Marble Initial micro-cracks Triaxial compression Constitutive relationship Crack evolution

Experimental and numerical study on dynamic mechanical behaviors of shale under true triaxial compression at high strain rate

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International Journal of Mining Science and Technology 2024年第2期34卷 149-165页

作者： Xiaoping Zhou Linyuan Han Jing Bi Yundong Shou school of civil engineering Wuhan UniversityWuhan 430072China College of civil engineering Guizhou UniversityGuiyang 550025China

High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing *** effectively extract shale gas,it is important to understand the dynamic mechanical properties of *** experiments on shale subjected to true triaxial compression at different strain rates are first conducted in this *** dynamic stress-strain curves,peak strain,peak stress and failure modes of shale are *** results of the study indicate that the intermediate principal stress and the minor principal stress have the significant influence on the dynamic mechanical behaviors,although this effect decreases as the strain rate *** characteristics of compression-shear failure primarily occur in shale subjected to triaxial compression at high strain rates,which distinguishes it from the fragmentation characteristics observed in shale under dynamic uniaxial ***,a numerical three-dimensional Split Hopkinson Pressure Bar(3D-SHPB),which is established by coupling PFC3D and FLAC3D methods,is validated to replicate the laboratory characteristics of *** dynamic mechanical characteristics of shale subjected to different confining stresses are systematically investigated by the coupling PFC3D and FLAC3D *** numerical results are in good agreement with the experimental data.

关键词： Dynamic behaviors True triaxial compression High strain rates Dynamic failure mechanism PFC3D-FLAC3D coupled method

Prediction model for corrosion rate of low-alloy steels under atmospheric conditions using machine learning algorithms

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 337-350页

作者： Jingou Kuang Zhilin Long school of civil engineering Xiangtan UniversityXiangtan 411105China

This work constructed a machine learning(ML)model to predict the atmospheric corrosion rate of low-alloy steels(LAS).The material properties of LAS,environmental factors,and exposure time were used as the input,while the corrosion rate as the output.6 dif-ferent ML algorithms were used to construct the proposed *** optimization and filtering,the eXtreme gradient boosting(XG-Boost)model exhibited good corrosion rate prediction *** features of material properties were then transformed into atomic and physical features using the proposed property transformation approach,and the dominant descriptors that affected the corrosion rate were filtered using the recursive feature elimination(RFE)as well as XGBoost *** established ML models exhibited better predic-tion performance and generalization ability via property transformation *** addition,the SHapley additive exPlanations(SHAP)method was applied to analyze the relationship between the descriptors and corrosion *** results showed that the property transformation model could effectively help with analyzing the corrosion behavior,thereby significantly improving the generalization ability of corrosion rate prediction models.

关键词： machine learning low-alloy steel atmospheric corrosion prediction corrosion rate feature fusion

Analytical Solutions for an Isotropic Elastic Half-Plane with Complete Surface Effects Subjected to a Concentrated/Uniform Surface Load

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Acta Mechanica Solida Sinica 2024年第3期37卷 371-384页

作者： Xia-Hui Pan school of civil engineering Henan Polytechnic UniversityJiaozuo454003China

Within the context of Gurtin-Murdoch surface elasticity theory,closed-form analytical solutions are derived for an isotropic elastic half-plane subjected to a concentrated/uniform surface *** the effects of residual surface stress and surface elasticity are *** stress function method and Fourier integral transform technique are *** solutions are provided in a compact manner that can easily reduce to special situations that take into account either one surface effect or none at *** results indicate that surface effects generally lower the stress levels and smooth the deformation profiles in the *** elasticity plays a dominant role in the in-plane elastic fields for a tangentially loaded half-plane,while the effect of residual surface stress is fundamentally crucial for the out-of-plane stress and displacement when the half-plane is normally *** the remaining situations,combined effects of surface elasticity and residual surface stress should be *** results for a concentrated surface force serve essentially as fundamental solutions of the Flamant and the half-plane Cerruti problems with surface *** solutions presented in this work may be helpful for understanding the contact behaviors between solids at the nanoscale.

关键词： Surface effects Residual surface stress Surface elasticity Half-plane Analytical solutions

Stability analysis of a liquid crystal elastomer self-oscillator under a linear temperature field

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 337-354页

作者： Haiyang WU Jiangfeng LOU Biao ZHANG Yuntong DAI Kai LI school of civil engineering Anhui Jianzhu UniversityHefei 230601China

Self-oscillating systems abound in the natural world and offer substantial potential for applications in controllers,micro-motors,medical equipments,and so ***,numerical methods have been widely utilized for obtaining the characteristics of self-oscillation including amplitude and ***,numerical methods are burdened by intricate computations and limited precision,hindering comprehensive investigations into self-oscillating *** this paper,the stability of a liquid crystal elastomer fiber self-oscillating system under a linear temperature field is studied,and analytical solutions for the amplitude and frequency are ***,we establish the governing equations of self-oscillation,elucidate two motion regimes,and reveal the underlying ***,we conduct a stability analysis and employ a multi-scale method to obtain the analytical solutions for the amplitude and *** results show agreement between the multi-scale and numerical *** research contributes to the examination of diverse self-oscillating systems and advances the theoretical analysis of self-oscillating systems rooted in active materials.

关键词： self-oscillation stability analysis multi-scale method liquid crystal elastomer linear temperature field

MXene:Promising materials for magnesium-ion batteries

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Chinese Journal of Chemical engineering 2024年第5期69卷 199-211页

作者： Liuyu Song Haibo Li Pengkai Wang Yu Shang Yue Yang Zhaoyu Wu school of Resources and civil engineering Northeastern UniversityShenyang 110004China

Magnesium-ion batteries(MIBs)have attracted extensive attention due to their high theoretical capacity,superior safety,and low ***,the development of MIBs is hindered by the lack of cathode materials with long cycle life and rate *** stands out as a prime choice for MIB cathode or collector for anode-free magnesium batteries(AFMBs)because of its larger surface area,adjustable surface properties,and good electrical *** this paper,we summarized the preparation and layering methods of MXene and discussed the prospects of MXene as a cathode or collector for *** review will be immensely beneficial in critically analyzing the synthesis techniques and the applications of MXene material as MIB cathode or AFMB *** addition,the challenges of the preparation and layering were concluded,along with raising the research strategies of MXene for storing Mg ions.

关键词： MXene Nanomaterials Electrochemistry Optimization Magnesium-ion batteries(MIBs)

Three-dimensional pseudo-dynamic reliability analysis of seismic shield tunnel faces combined with sparse polynomial chaos expansion

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Journal of Central South University 2024年第6期31卷 2087-2101页

作者： GUO Feng-qi LI Shi-wei ZOU Jin-Feng school of civil engineering Central South UniversityChangsha 410075China

To address the seismic face stability challenges encountered in urban and subsea tunnel construction,an efficient probabilistic analysis framework for shield tunnel faces under seismic conditions is *** on the upper-bound theory of limit analysis,an improved three-dimensional discrete deterministic mechanism,accounting for the heterogeneous nature of soil media,is formulated to evaluate seismic face *** metamodel of failure probabilistic assessments for seismic tunnel faces is constructed by integrating the sparse polynomial chaos expansion method(SPCE)with the modified pseudo-dynamic approach(MPD).The improved deterministic model is validated by comparing with published literature and numerical simulations results,and the SPCE-MPD metamodel is examined with the traditional MCS *** on the SPCE-MPD metamodels,the seismic effects on face failure probability and reliability index are presented and the global sensitivity analysis(GSA)is involved to reflect the influence order of seismic action ***,the proposed approach is tested to be effective by a engineering case of the Chengdu outer ring *** results show that higher uncertainty of seismic response on face stability should be noticed in areas with intense earthquakes and variation of seismic wave velocity has the most profound influence on tunnel face stability.

关键词： reliability analysis shield tunnel face sparse polynomial chaos expansion modified pseudo-dynamic approach seismic stability assessment

Dynamic Response of A Group of Cylindrical Storage Tanks with Baffles Considering the Effect of Soil Foundation

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China Ocean engineering 2024年第1期38卷 129-143页

作者： SUN Ying WANG Jia-dong HUO Rui-li ZHOU Ding GU Zhen-yuan QIAN Wang-ping school of Transportation and civil engineering Nantong UniversityNantong 226019China Faculty of civil engineering and Mechanics Jiangsu UniversityZhenjiang 212013China College of civil engineering Nanjing Tech UniversityNanjing 211816China

The sloshing in a group of rigid cylindrical tanks with baffles and on soil foundation under horizontal excitation is studied *** solutions for the velocity potential are derived out by the liquid subdomain *** models with mass-spring oscillators are established to replace continuous *** with the least square technique,Chebyshev polynomials are employed to fit horizontal,rocking and horizontal-rocking coupling impedances of soil,respectively.A lumped parameter model for impedance is presented to describe the effects of soil on tank structures.A mechanical model for the soil-foundation-tank-liquid-baffle system with small amount of calculation and high accuracy is proposed using the substructure *** analytical solutions are in comparison with data from reported literature and numerical codes to validate the effectiveness and correctness of the *** dynamic properties and seismic responses of the soil-tank system are given for the baffle number,size and location as well as soil parameter.

关键词： cylindrical tanks multiple annular baffles equivalent analytical model soil−structure interaction subdomain method dynamic response

Selection of digital fabrication technique in the construction industry--A multi-criteria decision-making approach

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Frontiers of Structural and civil engineering 2024年第7期18卷 977-997页

作者： M.P.SALAIMANIMAGUDAM J.JAYAPRAKASH Department of Structural and Geotechnical engineering School of Civil EngineeringVellore Institute of TechnologyVellore 632014India

Digital fabrication techniques,in recent decades,have provided the basis of a sustainable revolution in the construction ***,selecting the digital fabrication method in terms of manufacturability and functionality requirements is a complex *** paper presents alternatives and criteria for selection of digital fabrication techniques by adopting the multi-criteria decision-making *** alternatives considered in the study are concrete three-dimensional(3D)printing,shotcrete,smart dynamic casting,material intrusion,mesh molding,injection concrete 3D printing,and thin forming *** criteria include formwork utilization,reinforcement incorporation,geometrical complexity,material enhancement,assembly complexity,surface finish,and build *** demonstrates different multi-criteria decision-making techniques,with both subjective and objective weighting *** given ranking is based on the current condition of digital fabrication in the construction *** study reveals that in the selection of digital fabrication techniques,the criteria including reinforcement incorporation,build area,and geometrical complexity play a pivotal role,collectively accounting for nearly 70% of the overall *** the evaluated techniques,concrete 3D printing emerged as the best performer,however the shotcrete and mesh molding techniques in the second and third positions.

关键词： digital fabrication multicriteria decision-making concrete 3D printing