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Engineering 2022年第12期19卷 93-104页

作者： Jiepeng Liu Shu Huang Jiang Li y.frank chen School of Civil Engineering&Key Laboratory of New Technology for Construction of Cities in Mountain Area Ministry of EducationChongqing UniversityChongqing 400045China Central-South Architectural Design Institute Co. Ltd.Wuhan 430071China Department of Civil Engineering The Pennsylvania State UniversityPA 17057USA

A large-span steel–concrete composite beam with precast hollow core slabs(CBHCSs)is a relatively new floor structure that can be applied to various long-span ***,human-induced vibrations may present serviceability issues in such *** alleviate vibrations,both the walking forces excited by humans and the associated floor responses must be *** this study,150 load–time histories of walking,excited by 25 test participants,are obtained using a force measuring *** dynamic loading factors and phase angles in the Fourier series functions for one-step walking are ***,walking tests are performed on seven CBHCS specimens to capture the essential dynamic properties of mode shapes,natural frequencies,damping ratios,and acceleration time *** CBHCS floor system generally exhibits a high frequency(>10 Hz)and low damping(damping ratioy studies using the finite element method are conducted to investigate the vibration performance of the CBHCS floor system,where the floor thickness,steel beam type,contact time,and human weight are ***,analytical expressions derived for the fundamental frequency and peak acceleration agree well with the experimental results and are hence proposed for practical use.

关键词： Composite beam Hollow core slab Walking force Floor vibration Mode shape

Multi-population particle swarm optimization algorithm for automatic design of steel frames

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 89-103页

作者： Wenchen SHAN Jiepeng LIU yao DING y.frank chen Junwen ZHOU Institute of Smart City and Intelligent Transportation Southwest Jiaotong UniversityChengdu 610000China School of Civil Engineering Chongqing UniversityChongqing 400045China Department of Civil Engineering the Pennsylvania State UniversityMiddletownPA 17057USA

Steel structures are widely used;however,their traditional design method is a trial-and-error procedure which is neither efficient nor cost ***,a multi-population particle swarm optimization(MPPSO)algorithm is developed to optimize the weight of steel frames according to standard design *** are made to improve the algorithm performances including the constraint-based strategy,piecewise mean learning strategy and multi-population cooperative *** proposed method is tested against the representative frame taken from American standards and against other steel frames matching Chinese design *** related parameter influences on optimization results are *** the representative frame,MPPSO can achieve greater efficiency through reduction of the number of analyses by more than 65% and can obtain frame with the weight for at least 2.4%lighter.A similar trend can also be observed in cases subjected to Chinese design *** addition,a migration interval of 1 and the number of populations as 5 are recommended to obtain better MPPSO *** purpose of the study is to propose a method with high efficiency and robustness that is not confined to structural scales and design *** aims to provide a reference for automatic structural optimization design problems even with dimensional *** proposed method can be easily generalized to the optimization problem of other structural systems.

关键词： steel frame multi-population particle swarm optimization automatic structural optimization design

Predicting roof-surface wind pressure induced by conical vortex using a BP neural network combined with POD

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Building Simulation 2022年第8期15卷 1475-1490页

作者： Fubin chen Wen Kang Zhenru Shu Qiusheng Li yi Li yfrank chen Kang Zhou School of Civil Engineering Changsha University of Science and TechnologyChangsha410082China School of Civil Engineering Central South UniversityChangsha410083China Department of Architecture and Civil Engineering City University of Hong KongKowloonHong KongChina Hunan Provincial Key Laboratory of Structures for Wind Resistance and Vibration Control&School of Civil Engineering Hunan University of Science and TechnologyXiangtan411201China Department of Civil Engineering The Pennsylvania State UniversityMiddletownPA 17057USA

This study aims to examine the feasibility of predicting surface wind pressure induced by conical vortex using a backpropagation neural network(BPNN)combined with proper orthogonal decomposition(POD),in which a 1:150 scaled model with a large-span retractable roof was tested in wind tunnel under both laminar and turbulent flow *** distributions of mean and fluctuating wind pressure coefficients were first described,and the effects of inflow turbulence,wind direction,roof opening were examined *** the prediction of wind pressure,the POD-BPNN model was trained using measurement data from adjacent *** prediction results are overall *** root-mean-square-error(RMSE)between test and predicted data lies mostly within 10%.In particular,the prediction of mean wind pressure is found to be better than that of fluctuating wind *** outcomes in this study highlight that the proposed POD-BPNN model can be well used as a useful tool to predict surface wind pressure.

关键词： wind tunnel test-roof-surface wind pressure conical vortex proper orthogonal decomposition(POD) backpropagation neural network(BPNN)

步行激励下大跨度钢-混凝土空心板组合梁振动舒适度研究（英文）

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Engineering 2022年第12期 93-104+6页

作者：刘界鹏黄鉥李江 y.frank chen School of Civil Engineering&Key Laboratory of New Technology for Construction of Cities in Mountain Area Ministry of Education Chongqing University Central-South Architectural Design Institute Co. Ltd. Department of Civil Engineering The Pennsylvania State University

大跨度预制钢-混凝土空心板组合梁(CBHCS)是一种新型的楼板结构,可应用于各种大跨度结构。然而,人为引起的振动会对此类结构的使用性产生影响。为了减轻振动,需要探究由人引起的步行力和楼板状态之间的关系。本文首先使用测力板获取了2...

大跨度预制钢-混凝土空心板组合梁(CBHCS)是一种新型的楼板结构,可应用于各种大跨度结构。然而,人为引起的振动会对此类结构的使用性产生影响。为了减轻振动,需要探究由人引起的步行力和楼板状态之间的关系。本文首先使用测力板获取了25名测试者的150个步行力,确定了单步行走的傅里叶级数中的动态载荷系数和相位角。其次,对7个CBHCS试样进行了行走测试,获取了模态振型、固有频率、阻尼比和加速度等基本动态特性。CBHCS楼板系统通常表现出高频(>10 Hz)和低阻尼(阻尼比<2%)的特性。本文还使用有限元方法进行了灵敏度研究,以研究CBHCS楼板系统的振动性能,考虑了楼板厚度、钢梁类型、接触时间和人体重量。最后,本文推导了基频和峰值加速度的解析表达式,与实验结果吻合较好,具有实际应用的价值。

关键词：

重复压应力作用后再生混凝土中氯离子渗透性研究

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混凝土 2017年第1期 31-33页

作者：欧阳璋陈幼佳太原理工大学建筑与土木工程学院山西太原030024 美国宾夕法尼亚州立大学工程学院米德尔顿pa17057

再生混凝土对氯离子的渗透率也随荷载反复作用导致的混凝土内部的结构变化而变化,研究了重复荷载作用下对再生混凝土氯离子渗透性的影响。根据再生混凝土本身的承受应力状况,分别测量对普通混凝土和不同替代率的再生混凝土反复加卸载最... 详细信息

再生混凝土对氯离子的渗透率也随荷载反复作用导致的混凝土内部的结构变化而变化,研究了重复荷载作用下对再生混凝土氯离子渗透性的影响。根据再生混凝土本身的承受应力状况,分别测量对普通混凝土和不同替代率的再生混凝土反复加卸载最大压应力为45%fcy、80%fcy五次后的氯离子渗透性情况。研究表明:经5次加卸载后,再生混凝土氯离子渗透率比普通混凝土要高;反复施加5次荷载后,不同水灰比的再生混凝土与普通混凝土的渗透性,都随着水灰比的增大而增大;加卸载5次最大应力为45%fcy后,替代率不同的再生混凝土渗透性均比相应未加载混凝土大,最大荷载从45%fcy提高到80%fcy后,其氯离子渗透性进一步增大。

关键词：再生混凝土替代率重复荷载氯离子渗透性

Facile Li-Al layered double hydroxide films on Al alloy for enhanced hydrophobicity, anti-biofouling and anti-corrosion performance

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Journal of Materials Science & Technology 2021年第20期79卷 230-242页

作者： Ji Li Tianci yuan chengliang Zhou Bo chen yi Shuai Dawang Wu Dongchu chen Xiaohu Luo y.frank cheng yali Liu State Key Laboratory for Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha410082China Department of Mechanical and Manufacturing Engineering University of CalgaryCalgaryAlbertaT2N 1N4Canada School of Chemistry and Chemical Engineering Qiannan Normal University for NationalitiesDuyun558000China College of Mechanical Engineering and Applied Electronics Technology Beijing University of TechnologyBeijing100124China School of Material Science and Energy Engineering Foshan UniversityFoshan528000China

In this work,lithium(Li)-aluminum(Al)layered double hydroxide(LDH)films modified by 4-amino-2-((hydrazine methylene)amino)-4-oxobutanoic acid(denoted as AOA acid)and/or 1H,1H,2H,2H-perfluorooctyltriethoxysilane were prepared on 6N01 Al alloy by a facile,in-situ growth method with enhanced hydrophobicity,anti-biofouling and anti-corrosion *** preparation is low energy consumptive and environment friendly,relying on self-assembly at ambient *** structure,molecular weight and functional groups of the synthesized AOA acid were characterized by NMR spectrometer,ESI-MS spectrometer and Fourier transform infrared(FT-IR)*** the compositions,structure and morphology of the films were characterized by Fourier transform infrared(FT-IR)spectroscopy,glancing-angle X-ray diffraction(GA-XRD),X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FE-SEM)and energy-dispersive x-ray spectrum(EDS).Water contact angle measurements(CA)and atomic force microscopy(AFM)characterization show that the films possess a micro/nanostructure with an improved *** test,neutral salt tests(NSS)and electrochemical impedance spectroscopy(EIS)conducted in 3.5 wt.%NaCl solutions demonstrate the improved corrosion resistance of the films over bare Al ***,the films also possess an excellent anti-bacterial property toEscherichia coli,Bacillus subtilis and sulfate-reducing bacteria.

关键词： Li-Al layered double hydroxides Anti-biofouling Hydrophobicity Anti-bacterial Anti-corrosion

Condition evaluation of a unique mining site

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International Journal of Mining Science and Technology 2015年第6期25卷 1023-1029页

作者： Liu Junsheng chen frank y. Ma yan Zhang Siya Civil Engineering Academy Xi’an University of Architecture & Technology Shaanxi Academy of Building Research Institute of Architecture and Civil Engineering Taiyuan University of Technology Department of Civil Engineering 777 W Harrisburg Pike The Pennsylvania State University

The primary objective of this study was to evaluate the existing conditions and the stability of a mining site in which the unique features of seismicity, mining activity, hydrological conditions, geological conditions, environmental conditions, and future development plans were considered. In particular, the potential subsidence locations near the proposed construction site, the effects of mining boundary profile,and the influence scope of the mining activity on the neighboring areas were investigated using the finite element method. The study results indicate:(1) the overlying sandstone layer to the coal layer is the key to the stability of the mining roof;(2) the broken boundary has the most effect, followed by the arc boundary and linear boundary;(3) the safe distance from the mining boundary should be at least400 m if the proposed structure is to be built near an active mining site. Other relevant engineering recommendations are also proposed. The concluded results from this study may serve as a guide to other similar sites in the world.

关键词： MiningStabilityConditionEvaluationFinite element

Origin of enhanced stability in thiocyanate substituted α-FAPbI3 analogues

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Science China Chemistry 2019年第7期62卷 866-874页

作者： Zhuo Xu Ming chen Shengzhong (frank) Liu Key Laboratory of Applied Surface and Colloid Chemistry National Ministry of EducationShaanxi Key Laboratory for Advanced Energy DevicesShaanxi Engineering Lab for Advanced Energy TechnologyInstitute for Advanced Energy MaterialsSchool of Materials Science and Engineering Shaanxi Normal University Xi'an 710119 China State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China

In the past few years,hybrid perovskites have emerged as the most promising photovoltaic materials due to their excellent optoelectronic properties,and easy fabrication ***,the long-term stability is still the main obstacle for their commercial ***,thiocyanate-doped hybrid perovskites have shown enhanced stability and impressive efficiency,but the reason is still ***,we discussed the enhanced stability of SCN-substituted pseudocubic FABX3(B=Pb^2+,Sn^2+;X=I^–,Br^–,and Cl^–)based on the density functional *** a series of calculations of Bader charge transfer,vacancy formation energies of different kinds of vacancies,decomposition enthalpy,phonon density of states,and ab initio molecular dynamics simulation,we conclude that the incorporation of SCN–can stabilize pseudocubic FABX3,and attribute the enhanced stability mainly to two factors:(1)the strong interaction between Pb^2+/Sn^2+and SCN^–,as well as the strong hydrogen bonding between FA+and X^–/SCN^–,and(2)the structural tilting induced by the incorporation of SCN^–.These findings provide alternative method for tuning the poor stability of pseudocubic FABX3,as well as for obtaining high-performance solar cells.

关键词： thiocyanate stability formamidinium perovskites density-functional theory

Principle and Control of Active Engine Mount Based on Magnetostrictive Actuator

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Chinese Journal of Mechanical Engineering 2022年第6期35卷 363-376页

作者： Zhiyuan Si Xianxu‘frank’Bai Lijun Qian Peng chen Laboratory for Adaptive Structures and Intelligent Systems(LASIS) Department of Vehicle EngineeringHefei University of TechnologyHefei 230009China School of Mechanical Engineering Anhui Science and Technology UniversityFengyang 233100China Guangzhou Automobile Research and Design Center Guangzhou 511434China

Engine mount system affects the automobile NVH *** mounts would achieve excellent vibration isolation and relative displacement control performance in a broad frequency bandwidth by outputting controlled force to the mounting *** actuator and control method of the active mounts determine the system *** this paper,an active mount based on the smart material,i.e.,Terfenol-D rod,is proposed,which mainly includes three parts:rubber spring,magnetostrictive actuator(MA),and hydraulic amplification mechanism(HAM).Dynamic model of the active mount is correspondingly established.A state feedback control method based on x-LMS(Least-Mean-Square)algorithm is proposed as ***,with the consideration of the unmeasurable state parameters in the active mounting system,an x-LMS state feedback controller with the system state as the reference signal is constructed by employing Sage-Husa Kalman filter to realize the state estimation of the active mounting *** a detailed analysis of the proposed control method is conducted,with deriving iterative formula of tap-weight ***,the problem of the dependence on the excitation signal in the x-LMS algorithm is *** feasibility and capability of the proposed control method are verified and evaluated by simulation of a two-degree-offreedom active mounting system.

关键词： Terfenol-D rod x-LMS Sage-Husa Kalman filter Semi-active control Active mount controller

OPTIMAL POLICy WITH A TOTAL ORDER QUANTITy COMMITMENT CONTRACT IN THE PRESENCE OF A SPOT MARKET

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Journal of Systems Science and Systems Engineering 2011年第1期20卷 25-42页

作者： Wei ZHANG youhua (frank) chen Zhongsheng HUA Weili XUE School of Management University of Science and Technology of China Hefei China Department of Systems Engineering and Engineering Management The Chinese University of Hong Kong Shatin N. T. Hong Kong China yurun Corp. Nanjing China

In this paper, the optimal policy is considered when the buyer faces two supply sources： one is the contract supplier from which the buyer orders over a specific contract period （say, a year） at a pre-agreed price, and the other is the spot market. However, when ordering from the contract supplier, the buyer must fulfill a pre-determined total order quantity, or the so-called definite total order quantity commitment, over the whole contract period. In other words, the commitment secures the buyer a fixed price but obliges him/her a total order quantity over the contract period. Although the spot market gives the buyer more flexibility in terms of order quantities, its prices are volatile. Such a combination of contract and spot procurements is often observed in practice. Within the contract period, there are multiple sub-periods, during each of which the buyer reviews the inventory, issues an individual order, and uses the on-hand inventory to meet the random demand. Thus, in each （ordering） period, the buyer will weigh between the current known spot price （by procuring from the spot market） and a lower future price （by waiting while consuming the remaining commitment）. An optimal dual ordering policy is characterized for each period, depending on the on-hand inventory level, the spot price, and the remaining commitment quantity. The optimal policy in each period is also shown to be independent of the contract price. Through a numerical study, the inventory cost is demonstrated to be （1） insensitive to the contract price when the total commitment quantity is lower than the total expected demand over the contract period and （2） non-increasing in the variability of spot prices.

关键词： Total ordering quantity commitment (TOQC) spot market procurement policy