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Particuology 2024年第7期90卷 452-469页

作者： Abdulmuttalip Ari Suat Akbulut Department of civil engineering Yildiz Technical UniversityIstanbul34220Turkey

In this study,the effects of particle shape of rigid sand and soft rubber materials on macro-scale shear response were reasoned based on micro-scale *** this purpose,first,the shape properties of three different sand and two different rubber samples were quantified using image processing techniques,and the contact model parameters were calibrated through physical *** direct shear test was simulated in a two-dimensional discrete element software with realistic particle *** soft nature of rubber particles was reflected using body-centered cubic packing with a linear-parallel bond contact *** a result,coordination number,distribution of contact forces(i.e.,strong contact,and fabric anisotropy),and contact sliding were derived by the numerical *** has been observed that the particle shape leads to distinctive micro-scale responses due to the variations in the stiffness of the contacts.

关键词： Particle shape Sand Rubber Shear response Micro-scale response Discrete element method

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

A novel mitigation measure for normal fault-induced deformations on pile-raft systems

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Earthquake engineering and engineering Vibration 2024年第1期23卷 15-33页

作者： Mohammadreza Jahanshahi Nowkandeh Mehdi Ashtiani Faculty of civil engineering Babol Noshirvani University of TechnologyBabolIran

Evidence from recent earthquakes has shown destructive consequences of fault-induced permanent ground movement on *** observations have increased the demand for improvements in the design of structures that are dramatically vulnerable to surface fault *** this study a novel connection between the raft and the piles is proposed to mitigate the hazards associated with a normal fault on pile-raft systems by means of 3D finite element(FE)*** embarking on the parametric study,the strain-softening constitutive law used for numerical modeling of the sand has been validated against centrifuge test *** exact location of the fix-head and unconnected pile-raft systems relative to the outcropping fault rupture in the free-field is parametrically investigated,revealing different failure *** performance of the proposed connection for protecting the pile-raft system against normal fault-induced deformations is assessed by comparing the geotechnical and structural responses of both types of *** results indicate that the pocket connection can relatively reduce the cap rotation and horizontal and vertical displacements of the raft in most *** proposed connection decreases the bending moment response of the piles to their bending moment capacity,verging on a fault offset of 0.6 m at bedrock.

关键词： normal fault rupture failure mechanism pile-raft system pocket connection finite element modeling

Automatic detection and assessment of crack development in ultra-high performance concrete in the spatial and Fourier domains

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Frontiers of Structural and civil engineering 2024年第3期18卷 350-364页

作者： Jixing CAO Yao ZHANG Haijie HE Weibing PENG Weigang ZHAO Zhiguo YAN Hehua ZHU School of Safety engineering and Emergency Management Shijiazhuang Tiedao UniversityShijiazhuang 050043China College of civil engineering and Architecture Zhejiang UniversityHangzhou 310058China College of civil and Architectural engineering Taizhou UniversityTaizhou 318000China College of civil engineering and Architecture Zhejiang University of TechnologyHangzhou 310014China Department of Geotechnical engineering Tongji UniversityShanghai 200092China

Automatic detection and assessment of surface cracks are beneficial for understanding the mechanical performance of ultra-high performance concrete(UHPC).This study detects crack evolution using a novel dynamic mode decomposition(DMD)*** this method,the sparse matrix‘determined’from images is used to reconstruct the foreground that contains cracks,and the global threshold method is adopted to extract the crack *** application of the DMD method to the three-point bending test demonstrates the efficiency in inspecting cracks with high ***,the geometric features,including the area and its projection in two major directions,are evaluated over *** relationship between the geometric properties of cracks and load-displacement curves of UHPC is *** to the irregular shape of cracks in the spatial domain,the cracks are then transformed into the Fourier domain to assess their *** indicate that crack patterns in the Fourier domain exhibit a distinct concentration around a central ***,the power spectral density of cracks exhibits an increasing trend over *** investigation into crack evolution in both the spatial and Fourier domains contributes significantly to elucidating the mechanical behavior of UHPC.

关键词： dynamic mode decomposition ultra-high performance concrete crack detection geometric features Fourier domain

Bayesian Optimized LightGBM model for predicting the fundamental vibrational period of masonry infilled RC frames

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Frontiers of Structural and civil engineering 2024年第7期18卷 1084-1102页

作者： Taimur RAHMAN Pengfei ZHENG Shamima SULTANA Department of civil engineering World University of BangladeshDhaka 1230Bangladesh School of civil engineering Zhengzhou UniversityZhengzhou 450001China Department of Computer Science&engineering University of Asia PacificDhaka 1205Bangladesh

The precise prediction of the fundamental vibrational period for reinforced concrete(RC)buildings with infilled walls is essential for structural design,especially earthquake-resistant *** learning models from previous studies,while boasting commendable accuracy in predicting the fundamental period,exhibit vulnerabilities due to lengthy training times and inherent dependence on pre-trained models,especially when engaging with continually evolving data *** predicament emphasizes the necessity for a model that adeptly balances predictive accuracy with robust adaptability and swift data *** latter should include consistent re-training ability as demanded by realtime,continuously updated data *** research implements an optimized Light Gradient Boosting Machine(LightGBM)model,highlighting its augmented predictive capabilities,realized through the astute use of Bayesian Optimization for hyperparameter tuning on the FP4026 research data set,and illuminating its adaptability and efficiency in predictive *** results show that the R^(2) score of LightGBM model is 0.9995 and RMSE is 0.0178,while training speed is 23.2 times faster than that offered by XGBoost and 45.5 times faster than for Gradient ***,this study introduces a practical application through a streamlit-powered,web-based dashboard,enabling engineers to effortlessly utilize and augment the model,contributing data and ensuring precise fundamental period predictions,effectively bridging scholarly research and practical applications.

关键词： masonry-infilled RC frame fundamental period LightGBM FP4026 research dataset machine learning data-driven approach Bayesian Optimization

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

Microstructural analysis of marl stabilized with municipal solid waste and nano-MgO

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Journal of Rock Mechanics and Geotechnical engineering 2024年第8期16卷 3258-3269页

作者： Ali Ohadian Navid Khayat Mehdi Mokhberi Department of civil engineering Ahvaz BranchIslamic Azad UniversityAhvazIran Department of civil engineering Estahban BranchIslamic Azad UniversityEstahbanIran

Municipal solid waste(MSW)is accumulating over elapsed time across the world,and it is observed in many projects associated with weak soils,such as ***,effective solutions to the environmental problem are *** techniques for stabilizing marl generally use substances such as lime and cement,which could exacerbate *** this,some new stabilizers,***-MgO,are *** are large quantities of marls and MSW in Shiraz City,*** present study aims to evaluate the feasibility of using nano-MgO as a green low-carbon binder to remove MSW from the environment and make construction projects more *** drained shear tests were conducted to evaluate the mechanical behaviors of the nano-MgO treated marl specimens at high normal *** marl specimens containing MSW percentages of 15%,25%,35%,and 45%and nano-MgO percentages of 0.25%,0.5%,0.75%,and 1%,were *** is found that the marl containing 15%and 25%MSW and 0.5%nano-MgO at 28-d curing can perform cation exchange and form new cementitious *** soils with merely MSW show good performance due to the removal of the kaolinite and the formation of ***,the soil with 25%MSW and 0.5%nano-MgO shows the same strength enhancement as the specimen with the optimal nano-MgO(0.75%)through the formation of dolomite,with a 20.59%increase in strain energy(SE).

关键词： Marl Shear strength Microstructure Nano-MgO Municipal solid waste(MSW)

Bending strength degradation of a cantilever plate with surface energy due to partial debonding at the clamped boundary

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Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1573-1594页

作者： Zhenliang HU Xueyang ZHANG Xianfang LI School of civil engineering University of South ChinaHengyang 421001Hunan ProvinceChina School of civil engineering Central South UniversityChangsha 410075China

This paper investigates the bending fracture problem of a micro/nanoscale cantilever thin plate with surface energy,where the clamped boundary is partially debonded along the thickness *** fundamental mechanical equations for the bending problem of micro/nanoscale plates are given by the Kirchhoff theory of thin plates,incorporating the Gurtin-Murdoch surface elasticity *** two typical cases of constant bending moment and uniform shear force in the debonded segment,the associated problems are reduced to two mixed boundary value *** solving the resulting mixed boundary value problems using the Fourier integral transform,a new type of singular integral equation with two Cauchy kernels is obtained for each case,and the exact solutions in terms of the fundamental functions are determined using the PoincareBertrand *** elastic fields near the debonded tips including the bending moment,effective shear force,and bulk stress components exhibit the oscillatory *** dependence relations among the singular fields,the material constants,and the plate's thickness are analyzed for partially debonded cantilever *** surface energy is neglected,these results reduce the bending fracture of a macroscale partially debonded cantilever plate,which has not been previously reported.

关键词： micro/nanoscale cantilever plate partially debonded bending fracture singular integral equation oscillatory singularity

Numerical Exploration of Asymmetrical Impact Dynamics: Unveiling Nonlinearities in Collision Problems and Resilience of Reinforced Concrete Structures

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Structural Durability & Health Monitoring 2024年第3期18卷 223-254页

作者： AL-Bukhaiti Khalil Yanhui Liu Shichun Zhao Daguang Han School of civil engineering Southwest Jiaotong UniversityChengdu610031China Faculty of civil engineering Southeast UniversityNanjingChina

This study provides a comprehensive analysis of collision and impact problems’ numerical solutions, focusing ongeometric, contact, and material nonlinearities, all essential in solving large deformation problems during a *** initial discussion revolves around the stress and strain of large deformation during a collision, followedby explanations of the fundamental finite element solution method for addressing such issues. The hourglassmode’s control methods, such as single-point reduced integration and contact-collision algorithms are detailedand implemented within the finite element framework. The paper further investigates the dynamic responseand failure modes of Reinforced Concrete (RC) members under asymmetrical impact using a 3D discrete modelin ABAQUS that treats steel bars and concrete connections as bond slips. The model’s validity was confirmedthrough comparisons with the node-sharing algorithm and system energy relations. Experimental parameterswere varied, including the rigid hammer’s mass and initial velocity, concrete strength, and longitudinal and stirrupreinforcement ratios. Findings indicated that increased hammer mass and velocity escalated RC member damage,while increased reinforcement ratios improved impact resistance. Contrarily, increased concrete strength did notsignificantly reduce lateral displacement when considering strain rate effects. The study also explores materialnonlinearity, examining different materials’ responses to collision-induced forces and stresses, demonstratedthrough an elastic rod impact case study. The paper proposes a damage criterion based on the residual axialload-bearing capacity for assessing damage under the asymmetrical impact, showing a correlation betweendamage degree hammer mass and initial velocity. The results, validated through comparison with theoreticaland analytical solutions, verify the ABAQUS program’s accuracy and reliability in analyzing impact problems,offering valuable insights into collision

关键词： Geometric nonlinearity contact nonlinearity material nonlinearity collision problems finite element method stress and strain damage criterion RC members asymmetrical impact

Extending the decision-making process during yellow phase from human drivers to autonomous vehicles:A microsimulation study with safety considerations

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Journal of Traffic and Transportation engineering(English Edition) 2024年第2期11卷 362-379页

作者： Efthymis Papadopoulos Anastasia Nikolaidou Emmanouil Lilis Ioannis Politis Panagiotis Papaioannou Transport engineering Laboratory School of Civil EngineeringFaculty of EngineeringAristotle University of ThessalonikiThessaloniki 54124Greece

One of the main factors affecting the safety of signalised intersections is the stop/go behaviour during the yellow *** previous research has exhaustively examined drivers’stop/go decision-making,the expected autonomous vehicles’(AVs’)stop/go behaviour has not yet been thoroughly *** a series of simulation experiments developed for conventional and autonomous vehicles using different carfollowing,lane-changing,lateral placement and stop/go model parameter values,we examine here whether the default VISSIM stop/go parameter values can adequately replicate the observed drivers’behaviour at the considered intersection and assess the suitability of using the currently available options,albeit referring to human drivers,to simulate the expected stop/go behaviour of *** also propose a policy framework for determining the desired behaviour of AVs in yellow interval,which is integrated into an AVs logic and achieved in the last simulation to explore the effect of automation on the stop/go outcome and,hence,on the safety level of signalised *** data analysis and modeling techniques were used for the formulation of certain scenarios,including binary choice *** default stop/go parameter values were found unfit to replicate the observed stop/go behaviour and subjected to *** to the currently available options,the proposed AVs logic proved to produce the most accurate results,in terms of the stop/go simulation *** the impact of automation on the stop/go outcome,the simulation experiments showed that AVs preferred a more conservative behaviour in favor of road safety,as indicated by the significant reduction(≈15%)in the number of vehicles crossing the stop line during the yellow light and zero instances of red light ***,compared to the conservative drivers represented by the default stop/go parameter values,AVs preferred a more rational behaviour in favor of intersection capacit

关键词： Driver behaviour AVs behaviour Signalised intersection Choice model Micro-simulation Policy framework