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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

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Nonlinear vibration of Timoshenko FG porous sandwich beams subjected to a harmonic axial load

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Earthquake engineering and engineering Vibration 2024年第3期23卷 649-662页

作者： Milad Lezgi Moein Zanjanchi Nikoo Majid Ghadiri Department of civil engineering Sharif University of TechnologyTehran ***Iran civil engineering Department K.N.Toosi University of TechnologyTehran ***Iran Faculty of engineering Department of MechanicsImam Khomeini International UniversityQazvin ***Iran

In this study,the instability and bifurcation diagrams of a functionally graded(FG)porous sandwich beam on an elastic,viscous foundation which is influenced by an axial load,are investigated with an analytical *** do so,the Timoshenko beam theory is utilized to take the shear deformations into account,and the nonlinear Von-Karman approach is adopted to acquire the equations of ***,to turn the partial differential equations(PDEs)into ordinary differential equations(ODEs)in the case of equations of motion,the method of Galerkin is employed,followed by the multiple time scale method to solve the resulting *** impact of parameters affecting the response of the beam,including the porosity distribution,porosity coefficient,temperature increments,slenderness,thickness,and damping ratios,are explicitly *** is found that the parameters mentioned above affect the bifurcation points and instability of the sandwich porous beams,some of which,including the effect of temperature and porosity distribution,are less noticeable.

关键词： sandwich beam Timoshenko beam parametric excitation bifurcation diagrams dynamic instability

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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

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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)

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Transfer learning-based encoder-decoder model with visual explanations for infrastructure crack segmentation:New open database and comprehensive evaluation

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Underground Space 2024年第4期17卷 60-81页

作者： Fangyu Liu Wenqi Ding Yafei Qiao Linbing Wang Illinois Center for Transporation Department of Civil and Environmental EngineeringUniversity of Illinois Urbana-ChampaignIllinois 61801USA Department of Geotechnical engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground engineering of the Ministry of Education Tongji UniversityShanghai 200092China School of Environmental CivilAgricultural and Mechanical EngineeringUniversity of GeorgiaGeorgia 30602USA

Contemporary demands necessitate the swift and accurate detection of cracks in critical infrastructures,including tunnels and *** study proposed a transfer learning-based encoder-decoder method with visual explanations for infrastructure crack ***,a vast dataset containing 7089 images was developed,comprising diverse conditions—simple and complex crack patterns as well as clean and rough ***,leveraging transfer learning,an encoder-decoder model with visual explanations was formulated,utilizing varied pre-trained convolutional neural network(CNN)as the *** explanations were achieved through gradient-weighted class activation mapping(Grad-CAM)to interpret the CNN segmentation ***,accuracy,complexity(computation and model),and memory usage assessed CNN feasibility in practical *** performance was gauged via prediction and visual *** investigation encompassed hyperparameters,data augmentation,deep learning from scratch *** learning,segmentation model architectures,segmentation model encoders,and encoder pre-training *** underscored transfer learning’s potency in enhancing CNN accuracy for crack segmentation,surpassing deep learning from ***,encoder classification accuracy bore no significant correlation with CNN segmentation *** all tested models,UNet-EfficientNet_B7 excelled in crack segmentation,harmonizing accuracy,complexity,memory usage,prediction,and visual explanation.

关键词： Crack segmentation Transfer learning Visual explanation Infrastructure Database

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Effects of Using Municipal Solid Waste Incineration Tailings as Lightweight Aggregate on the Mechanical Properties of Specified Density Concrete

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1229-1245页

作者： SHANG Minggang FENG Qiong ZHANG Yunsheng HE Zhongmao QIAO Hongxia XUE Cuizhen WANG Jinpen HAN Yuehui School of civil engineering Lanzhou University of TechnologyLanzhou 730050China Gansu Advanced civil engineering Materials engineering Research Center Lanzhou 730050China College of Science&Technology Ningbo UniversityNingbo 315211China

Municipal solid waste incineration tailings were used as lightweight aggregate(MSWIT-LA)in the preparation of specified density concrete to study the effects on compressive strength,axial compressive strength,flexural strength,microhardness,total number of pores,pore area,and pore *** results showed that the internal curing and morphological effects induced by an appropriate quantity of MSWIT-LA improved the compressive response of specified density concrete specimens,whereas an excessive quantity of MSWIT-LA significantly reduced their mechanical *** analysis of pore structure indicated that the addition of MSWIT-LA increased the total quantity of pores and promoted cement hydration,resulting in a denser microstructure than that of ordinary *** results of a principal component analysis showed that the mechanical response of specified density concrete prepared with 25%MSWIT-LA was superior to that of an equivalent ordinary *** was therefore concluded that MSWIT-LA can be feasibly applied to achieve excellent specified density concrete properties while utilising municipal solid waste incineration tailings to protect the environment and alleviate shortages of sand and gravel resources.

关键词： municipal solid waste incineration tailings X-ray computed tomography lightweight aggregate microhardness principal component analysis

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Exploring the Applications of Digital Twin Technology in Enhancing Sustainability in civil engineering:A Review

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Structural Durability & Health Monitoring 2024年第5期18卷 577-598页

作者： Jiamin Huang Ping Wu Wangxin Li Jun Zhang Yidong Xu School of civil engineering Chongqing Jiaotong UniversityChongqing400074China School of civil engineering and Architecture NingboTech UniversityNingbo315100China School of civil engineering Lanzhou University of TechnologyLanzhou730050China

With the advent of the big data era and the rise of Industrial Revolution 4.0,digital twins(DTs)have gained sig-niﬁcant attention in various *** offer the opportunity to combine the physical and digital worlds and aid the digital transformation of the civil engineering *** this paper,605 documents obtained from the search wereﬁrst analysed using CiteSpace for literature visualisation,and an author co-occurrence network,a keyword co-occurrence network,and a keyword clustering set were ***,through a literature review of 86 papers,this paper summarises the current status of DT application in civil engineering based on a review of the origins,concepts,and implementation techniques of DTs,and it introduces the application of DTs in the full project *** study shows that DTs have great potential to address many of the challenges faced by civil *** this regard,the paper also presents some thoughts on the future directions of DT research.

关键词： Digital twins civil engineering full lifecycle literature visualisation analysis

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Numerical simulation analysis of tunnel backfill grout based on DEM-FDM coupling and particle inlet

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Underground Space 2024年第1期14卷 285-299页

作者： Bin Yan Rui Wang Bo-song Ding Fang Dai You Wang School of civil engineering Central South University.Changsha 410075China

Shield tunnel backfill grouting is vital to stabilize tunnel settlement at a later stage;however,most shield tunnel backfill grouting designs lack a complete theoretical reference,and numerical simulations of the grouting process are rarely *** study presents the fundamental theories of grout diffusion and pressure variation for backfill grouting during shield ***,the numerical simulation methods coupled with discrete element methods(DEM)and finite difference methods(FDM)are achieved to simulate the process of grout injection from the grouting hole into the shield tail gap and generate grout pressure on the surrounding *** diffusion state of the grout in the shield tail gap and the squeezing effect on the surrounding rock under two shield tail disengagement modes are analyzed,as well as the impact of various grouting pressure on the surface *** results indicated that the grout diffusion in the shield tail gap can be divided into three stages:the stage of diffusion with each grouting hole as the starting point,the stage of interconnection and contact of the grout injected in each grouting hole,and the final gap filling *** of the three stages can be described using the proposed *** the grouting process,the grout is injected into the shield tail gap at a certain pressure,but the grout diffuses slowly to both sides and upwards,which causes a rapid rise of the principal stresses in the soil around the *** grouting is complete,the grout pressure gradually dissipates and stabilizes,and the principal stress *** addition,backfill grouting can reduce surface settlement,but it does not affect its distribution width.

关键词： Shield tunnel Backfill grouting Discrete element Finite difference Particle generator

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Resilience-incorporated seismic risk assessment of precast concrete frames with“dry”connections

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Earthquake engineering and engineering Vibration 2024年第2期23卷 403-425页

作者： Wu Chenhao Tang Yuchuan Cao Xuyang Wu Gang Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education Nanjing 211102China Department of civil and Environmental engineering University of CaliforniaLos AngelesCA 90095USA School of civil engineering Southeast UniversityNanjing 211102China College of civil and Transportation engineering Hohai UniversityNanjing 210024China

A resilience-incorporated risk assessment framework is proposed and demonstrated in this study to manifest the advantageous seismic resilience of precast concrete frame(PCF)structures with“dry”connections in terms of their low damage and rapid *** framework integrates various uncertainties in the seismic hazard,fragility,capacity,demand,loss functions,and post-earthquake *** this study,the PCF structures are distinguished from ordinary reinforced concrete frame(RCF)structures by characterizing multiple limit states for the PCF based on its unique damage ***,probabilistic story-wise pushover analyses are performed to yield story-wise capacities for the predefined limit *** the seismic resilience analysis,a step-wise recovery model is proposed to idealize the functionality recovery process,with separate considerations of the repair and non-repair *** recovery model leverages the economic loss and downtime to delineate the stochastic post-earthquake recovery curves for the resilience loss *** such,contingencies in the probabilistic post-earthquake repairs are incorporated and the empirical judgments on the recovery parameters are largely *** proposed framework is demonstrated through a comparative study between two“dry”connected PCFs and one RCF designed as alternative structural systems for a prototype *** results from the risk quantification indicate that the PCFs show reduced loss hazards and lower expected losses relative to the ***,the PCF equipped with energy dissipation devices at the“dry”connections largely reduces the expected economic loss,downtime,and resilience loss by 29%,56%,and 60%,respectively,compared to the RCF.

关键词： precast concrete frame non-emulative precast system seismic resilience seismic risk functional recovery

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Dynamic Response Impact of Vehicle Braking on Simply Supported Beam Bridges with Corrugated Steel Webs Based on Vehicle-Bridge Coupled Vibration Analysis

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Computer Modeling in engineering & Sciences 2024年第6期139卷 3467-3493页

作者： Yan Wang Siwen Li Na Wei School of civil engineering Zhengzhou UniversityZhengzhou450001China

A novel approach for analyzing coupled vibrations between vehicles and bridges is presented,taking into account spatiotemporal effects and mechanical phenomena resulting fromvehicle *** modeling and solution of bridge vibrations induced by vehicle deceleration are realized using this *** method’s validity and reliability are substantiated through numerical examples.A simply supported beam bridge with a corrugated steel web is taken as an example and the effects of parameters such as the initial vehicle speed,braking acceleration,braking location,and road surface roughness on the mid-span displacement and impact factor of the bridge are *** results show that vehicle braking significantly amplifies mid-span displacement and impact factor responses in comparison to uniform vehicular motion across the ***,the influence of wheelto-bridge friction forces is of particular significance and cannot be *** the vehicle initiates braking near the middle of the span,both the mid-span displacement and impact factor of the bridge exhibit substantial increases,further escalating with higher braking *** favorable road surface conditions,the midspan displacement and the impact factor during vehicle braking may exceed the design values stipulated by *** is important to note that road surface roughness exerts a more pronounced effect on the impact factor of the bridge in comparison to the effects of vehicle braking.

关键词： Corrugated steel web girder bridges simply supported beam bridges vehicle-bridge coupled vibration braking impact factor

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