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Corrosion behavior and protection mechanism of carbon steel coated with ethylene chlorotrifluoroethylene(ECTFE)

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 502-515页

作者： Peihu SHEN Jun WEN Biqin DONG Hedong LI Minjia WANG School of civil Engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou310018China college of civil and Transportation Engineering Shenzhen UniversityShenzhen518061China Zhejiang Research Institute of Chemical Industry Co. Ltd.Hangzhou310023China

Ethylene chlorotrifluoroethylene(ECTFE)coating was applied to the surface of carbon steel through electrostatic spraying and low-temperature heat *** morphology and structure of the coating were analyzed using various characterization *** electrochemical data of the coated steel soaked in 3.5%(mass fraction)NaCl solution for 90 d at different periods were also *** findings indicate that the outer surface of the coating remains structurally stable before and after soaking.F can diffuse into the steel substrate,facilitating the bonding between the coating and the steel substrate,but the free F also induces a weakening effect on the crystalline *** to the thickness of the coating edge and the susceptibility to infiltration of the corrosive medium,under-film micro-zone corrosion occurs at a slow *** soaking for 90 d,the impedance modulus measures approximately 10^(4)Ω·cm^(2),and the open circuit potential(OCP)is−0.61 *** self-corrosion current density is 1.13×10^(−6)A/cm^(2),resulting in a calculated coating protection rate of 99.29%.In summary,despite edge corrosion occurring,the ECTFE coating provides excellent corrosion protection.

关键词： Coating Fluorine resin Edge corrosion Corrosive behavior Electrochemical performance

A Deep Learning Approach to Shape Optimization Problems for Flexoelectric Materials Using the Isogeometric Finite Element Method

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1935-1960页

作者： Yu Cheng Yajun Huang Shuai Li Zhongbin Zhou Xiaohui Yuan Yanming Xu college of Architecture and civil Engineering Xinyang Normal UniversityXinyang464000China Henan Unsaturated Soil and Special Soil Engineering Technology Research Center Xinyang Normal UniversityXinyang464000China college of Intelligent Construction Wuchang University of TechnologyWuhan430223China college of civil Engineering and Architecture Dalian UniversityDalian116622China Henan International Joint Laboratory of Structural Mechanics and Computational Simulation School of Architecture and Civil EngineeringHuanghuai UniversityZhumadian463000China

A new approach for flexoelectricmaterial shape optimization is proposed in this *** this work,a proxymodel based on artificial neural network(ANN)is used to solve the parameter optimization and shape optimization *** improve the fitting ability of the neural network,we use the idea of pre-training to determine the structure of the neural network and combine different optimizers for *** isogeometric analysis-finite element method(IGA-FEM)is used to discretize the flexural theoretical formulas and obtain samples,which helps ANN to build a proxy model from the model shape to the target *** effectiveness of the proposed method is verified through two numerical examples of parameter optimization and one numerical example of shape optimization.

关键词： Shape optimization deep learning flexoelectric structure finite element method isogeometric

Predicting the International Roughness Index of JPCP and CRCP Rigid Pavement:A Random Forest(RF)Model Hybridized with Modified Beetle Antennae Search(MBAS)for Higher Accuracy

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1557-1582页

作者： Zhou Ji Mengmeng Zhou Qiang Wang Jiandong Huang college of civil and Environmental Engineering Hunan University of Science and EngineeringYongzhou425006China School of Mines China University of Mining and TechnologyXuzhou221116China School of civil Engineering Guangzhou UniversityGuangzhou510006China

To improve the prediction accuracy of the International Roughness Index(IRI)of Jointed PlainConcrete Pavements(JPCP)and Continuously Reinforced Concrete Pavements(CRCP),a machine learning approach is developed in this study for the modelling,combining an improved Beetle Antennae Search(MBAS)algorithm and Random Forest(RF)*** 10-fold cross-validation was applied to verify the reliability and accuracy of the model proposed in this *** importance scores of all input variables on the IRI of JPCP and CRCP were analysed as *** results by the comparative analysis showed the prediction accuracy of the IRI of the newly developed MBAS and RF hybrid machine learning model(RF-MBAS)in this study is higher,indicated by the RMSE and R values of 0.2732 and 0.9476 for the JPCP as well as the RMSE and R values of 0.1863 and 0.9182 for the *** accuracy of this obtained result far exceeds that of the IRI prediction model used in the traditional Mechanistic-Empirical Pavement Design Guide(MEPDG),indicating the great potential of this developed *** importance analysis showed that the IRI of JPCP and CRCP was proportional to the corresponding input variables in this study,including the total joint faulting cumulated per KM(TFAULT),percent subgrade material passing the 0.075-mm Sieve(P_(200))and pavement surface area with flexible and rigid patching(all Severities)(PATCH)which scored higher.

关键词： Cement pavement JPCP CRCP RF-MBAS IRI

A new neural-network-based method for structural damage identification in single-layer reticulated shells

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Frontiers of Structural and civil Engineering 2024年第1期18卷 104-121页

作者： Jindong ZHANG Xiaonong GUO Shaohan ZONG Yujian ZHANG college of civil Engineering Tongji UniversityShanghai 200092China China Construction Eighth Engineering Division Co. Ltd.Shanghai 200135China

Single-layer reticulated shells(SLRSs)find widespread application in the roofs of crucial public structures,such as gymnasiums and exhibition *** this paper,a new neural-network-based method for structural damage identification in SLRSs is ***,a damage vector index,NDL,that is related only to the damage localization,is proposed for SLRSs,and a damage data set is constructed from NDL *** the basis of visualization of the NDL damage data set,the structural damaged region locations are identified using convolutional neural networks(CNNs).By cross-dividing the damaged region locations and using parallel CNNs for each regional location,the damaged region locations can be quickly and efficiently identified and the undamaged region locations can be ***,a damage vector index,DS,that is related to the damage location and damage degree,is proposed for *** on the damaged region identified previously,a fully connected neural network(FCNN)is constructed to identify the location and damage degree of *** effectiveness and reliability of the proposed method are verified by considering a numerical case of a spherical *** calculation results showed that the proposed method can quickly eliminate candidate locations of potential damaged region locations and precisely determine the location and damage degree of members.

关键词： single-layer reticulated shell damage identification neural network convolutional neural network cross-partitioning method

Space debris environment engineering model 2019:Algorithms improvement and comparison with ORDEM 3.1 and MASTER-8

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Chinese Journal of Aeronautics 2024年第5期37卷 392-409页

作者： Yuyan LIU Runqiang CHI Baojun PANG HU Diqi Wuxiong CAO Dongfang WANG School of Astronautics Harbin Institute of TechnologyHarbin 150001China college of Safety Science&Engineering Civil Aviation University of ChinaTianjin 300300China

As an essential tool for realistic description of the current or future debris environment,the Space Debris Environment Engineering Model(SDEEM)has been developed to provide support for risk assessment of *** contrast with SDEEM2015,SDEEM2019,the latest version,extends the orbital range from the Low Earth Orbit(LEO)to Geosynchronous Orbit(GEO)for the years *** this paper,improved modeling algorithms used by SDEEM2019 in propagating simulation,spatial density distribution,and spacecraft flux evaluation are *** debris fluxes of SDEEM2019 are compared with those of three typical models,i.e.,SDEEM2015,Orbital Debris Engineering Model 3.1(ORDEM 3.1),and Meteoroid and Space Debris Terrestrial Environment Reference(MASTER-8),in terms of two assessment *** orbital cases,including the Geostationary Transfer Orbit(GTO),Sun-Synchronous Orbit(SSO)and International Space Station(ISS)orbit,are selected for the spacecraft assessment mode,and the LEO region is selected for the spatial density assessment *** analysis indicates that compared with previous algorithms,the variable step-size orbital propagating algorithm based on semi-major axis control is more precise,the spatial density algorithm based on the second zonal harmonic of the non-spherical Earth gravity(J_(2))is more applicable,and the result of the position-centered spacecraft flux algorithm is more *** comparison shows that SDEEM2019 and MASTER-8 have consistent trends due to similar modeling processes,while the differences between SDEEM2019 and ORDEM 3.1 are mainly caused by different modeling approaches for uncatalogued debris.

关键词： SDEEM2019 Space debris propagating algorithm Spatial density algorithm ORDEM 3.1 MASTER-8

Economic analysis of rooftop photovoltaics system under different shadowing conditions for 20 cities in China

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Building Simulation 2024年第2期17卷 235-252页

作者： Zhiyi Ren Yixing Chen Chengcheng Song Mengyue Liu Anni XuQilin Zhang college of civil Engineering Hunan UniversityChangsha410082China Key Laboratory of Building Safety and Energy Efficiency of Ministry of Education Hunan UniversityChangsha410082China

Installing photovoltaic(PV)systems is an essential step for low-carbon *** economics of PV systems are strongly impacted by the electricity price and the shadowing effect from neighboring *** study evaluates the PV generation potential and economics of 20 cities in China under three shadowing ***,the building geometry models under three shadowing conditions for the 20 cities were constructed using ***,60 building models with PV systems and shadows from surrounding buildings were generated by City Buildings,Energy,and Sustainability(CityBES),an open platform,to simulate the PV power ***,the study presented one economic analysis model to evaluate the profitability by combining the market cost of rooftop PV systems and electricity prices in *** economic model included four indicators:payback period(static and dynamic),net present value(NPV),and internal rate of return(IRR).The results show that the reduction of PV power generation ranges from 8.29%to 16.01%under medium shadowing,and experiences a maximum decrease of up to 39.71%under high *** economic analysis shows that almost all the regions show reliable potential,obtaining an IRR higher than the reference value(5%).Nenjiang has the highest economic profit,with the highest NPV(86,181.15 RMB)and IRR(30.14%)under no shadowing among 20 *** also should be mentioned that the alignment between electricity price distribution and the solar power generation curve will directly impact the economic potential of PV systems.

关键词： rooftop photovoltaic system EnergyPlus economic analysis shadowing buildings electric price

Comparison of the hygrothermal performance of two light-framed timber structure buildings under different operation modes

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第1期25卷 18-35页

作者： Wanqing XU Yucong XUE Jiang LU Yifan FAN Xiaoyu LUO college of civil Engineering and Architecture Zhejiang UniversityHangzhou310058China International Research Center for Green Building and Low-Carbon City International CampusZhejiang UniversityJiaxing314400China School of civil Engineering and Architecture Zhejiang University of Science and TechnologyHangzhou310023China

Light-framed timber structure(LTS)buildings have been highly valued in recent years due to their low-carbon ***,the applicability of the building envelope is closely related to indoor and outdoor *** hot summer and cold winter(HSCW)climate zone in China has high humidity and great temperature variation throughout the year,resulting in distinct outdoor environments in different *** indoor environment is greatly affected by energy-consumption patterns and window-opening habits,which largely depend upon the regulation operations of *** these interrelated factors lead to extremely complex boundary conditions on each side of the building *** the structures of LTS buildings are applicable in this climate zone,therefore,needs to be carefully *** this study,two LTS buildings with different envelopes were established in Haining,China,situated in the HSCW climate zone,and selected as the study *** operation modes were adopted to create a variety of indoor *** each condition,the processes of heat and moisture transfer within the building envelopes and the indoor environment were monitored and *** comparison indicated that the building envelope with high moisture storage and insulation ability maintained a relatively stable indoor environment,especially when the environment changed ***,if the outdoor environment was equable(e.g.,relative humidity within the range of 30%–60%)or intermittent energy consumption modes were adopted,the building envelope with a low thermal inertia index and weak moisture-buffering ability performed better because it enabled a faster response of the indoor environment to air ***,a high risk of moisture accumulation between the thermal insulation layer and other materials with a large water vapour transfer resistance factor was also identified,suggesting a higher requirement for the vapour insulation of the env

关键词： Light-framed timber structure(LTS)buildings In-situ experiment Typical operation mode Indoor environment Heatand moisture transfer

Three-dimensional limit variation analysis on the ultimate pullout capacity of the anchor cables based on the Hoek-Brown failure criterion

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Journal of Mountain Science 2024年第3期21卷 1036-1047页

作者： ZUO Shi ZHAO Lianheng HU Shihong college of civil Engineering Changsha UniversityChangsha 410022China Hunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering Structure Key Laboratory of Heavy-Haul Railway Engineering StructureMinistry of EducationCentral South UniversityChangsha 410075China college of civil Engineering Central South UniversityChangsha 410075China

Only simplified two-dimensional model and a single failure mode are adopted to calculate the ultimate pullout capacity(UPC)of anchor cables in most previous *** study focuses on a more comprehensive combination failure mode that consists of bond failure of an anchorage body and failure of an anchored rock *** three-dimensional ultimate pullout capacity of the anchor cables is calculated based on the Hoek-Brown failure criterion and variation analysis *** numerical solution for the curvilinear function in fracture plane is obtained based on the finite difference theory,which more accurately reflects the failure state of the anchor cable,as opposed to that being assumed in *** results reveal that relying solely on a single failure mode for UPC calculations has limitations,as changes in parameter values not only directly impact the UPC value but also can alter the failure model and thus the calculation method.

关键词： Anchor cable Ultimate pullout capacity(UPC) Failure model Variation analysis Hoek-Brown failure criterion

Generalized nth-Order Perturbation Method Based on Loop Subdivision Surface Boundary Element Method for Three-Dimensional Broadband Structural Acoustic Uncertainty Analysis

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Computer Modeling in Engineering & Sciences 2024年第8期140卷 2053-2077页

作者： Ruijin Huo Qingxiang Pei Xiaohui Yuan Yanming Xu college of Architecture and civil Engineering Xinyang Normal UniversityXinyang464000China Henan Unsaturated Soil and Special Soil Engineering Technology Research Center Xinyang Normal UniversityXinyang464000China Henan International Joint Laboratory of Structural Mechanics and Computational Simulation College of Architecture and Civil EngineeringHuanghuai UniversityZhumadian463000China

In this paper,a generalized nth-order perturbation method based on the isogeometric boundary element method is proposed for the uncertainty analysis of broadband structural acoustic scattering *** Burton-Miller method is employed to solve the problem of non-unique solutions that may be encountered in the external acoustic field,and the nth-order discretization formulation of the boundary integral equation is *** addition,the computation of loop subdivision surfaces and the subdivision rules are *** order to confirm the effectiveness of the algorithm,the computed results are contrasted and analyzed with the results under Monte Carlo simulations(MCs)through several numerical examples.

关键词： Perturbation method loop subdivision surface isogeometric boundary element method uncertainty analysis