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A novel smart steel strand based on optical-electrical co-sensing for full-process and full-scale monitoring of prestressing concrete structures

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International Journal of Smart and Nano Materials 2023年第3期14卷 337-368页

作者： Huanyu Yang Zhi Zhou jinping ou Faculty of Infrastructure Engineering Dalian University of TechnologyDalianLiaoning 116024China School of Civil and Architectural Engineering Hainan UniversityHaikouHainanChina Harbin Institute of Technology(Shenzhen) School of Civil and Environmental EngineeringShenzhenGuangdongChina

As the main load bearing component,the steel strand has a significant impact on the safety of civil infrastructure.Real-time monitoring of steel strand stress distribution throughout the damage process is an impor-tant aspect of civil infrastructure health assessment.Hence,this study proposes an optical-electrical co-sensing(OECS)smart steel strand with the DOFS and CCFPI embedded in.It can simultaneously measure small strains in the initial damage phase with high accuracy and obtain information in the large deformation phase with relatively low precision.Several experiments were carried out to test its sensing performance.It shows both DOFS and CCFPI have good linearity,repeatability and hysteresis.In comparison to DOFS,CCFPI has a relatively lower accuracy and resolution,but a large enough measurement range to tolerate the large strain in the event of a steel strand failure.To verify the reliability of the proposed smart steel strand in real structures,the strand strain distribution in the full damage process of bonded prestressed beams under four-point bending loading was monitored using the smart steel strand as a prestressing tendon.The strain measured by the OECS steel strand is shown to reflect the deformation and stiffness variation of prestressed beams under different load.

关键词： Distributed optical fiber sensor(DOFS) Coaxial cable fabry–perot interferometer(CCFPI) Smart steel strand Prestress monitoring Optical-electrical co-sensing

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Development and sensing performance study of a smart CFRP cable assembled by multi-group anchorage units

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International Journal of Smart and Nano Materials 2023年第3期14卷 286-302页

作者： Lian Shao Huanyu Yang jinping ou Zhi Zhou Faculty of Infrastructure Engineering Dalian University of TechnologyDalian 116024China School of Civil Engineering Harbin Institute of TechnologyHarbinChina School of Civil Engineering and Architecture Hainan UniversityHaikouChina

Carbon fiber reinforced polymer(CFRP)can be applied for bridge cables due to its excellent properties.As the important load-bearing structural component,real-time force monitoring of the CFRP cable is required.This paper presents a new smart CFRP cable that combines the self-sensing rods with embedded sensors and the anchorage system using extrusion technology.By embedding optical fiber(OF)and coaxial cable Fabry-Perot interferometer(CCFPI)into CFRP rods respectively,two types of self-sensing rods(CFRP-OF rod and CFRP-CCFPI rod)were fabricated.A new anchorage unit using an extrusion process was proposed as a basic component of smart CFRP cables.Anchorage units holding a CFRP-OF rod and a CFRP-CCFPI rod were tested to obtain their sensing and mechanical properties.Three ancho-rage units were assembled to form a smart CFRP cable with self-sensing functionality.A verification test was carried out to confirm the capabil-ity of monitoring the cable force.The test results demonstrate that the smart CFRP cable composed of multiple anchorage units has good potential in bridge engineering.

关键词： Carbon fiber reinforced polymer smart cable sensor extrusion process bridge engineering

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Long-term performance of packaged fiber Bragg grating sensors for strain monitoring inside creep medium

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International Journal of Smart and Nano Materials 2022年第1期13卷 42-63,I0003页

作者： Huanyu Yang Ying Huang Zhi Zhou jinping ou Faculty of Infrastructure Engineering Dalian University of TechnologyDalian116024Liaoning ProvinceChina Department of Civil and Environmental Engineering North Dakota State UniversityFargoNorth DakotaUSA Hainan University School of Civil and Architectural EngineeringHaikou570228Hainan ProvinceChina School of Civil and Environmental Engineering Harbin Institute of Technology(Shenzhen)ShenzhenGuangdong ProvinceChina

To investigate the long-term performance of the packaged fiber Bragg grating(FBG)sensors embedded in civil infrastructure for strain monitoring,in this paper,the influence of host matrix’s creep effect on the behavior of the FBG sensors was systematically studied through theoretical,numerical,and experimental analysis.A theoretical strain transfer analysis between the optic fiber,packaging layer,and host matrix to consider the creep effect of the host matrix was performed accordingly for long-term strain monitoring.Parametric studies were carried out using numerical analysis for FBG sensors packaged with glass fiber reinforced plastic(GFRP),also known as FBG-GFRP sensors in concrete,as an example.The results show that embedded in a creep medium,an acceptable long-term performance of packaged FBG sensors requires the packaging layer to have a minimum length and maximum thickness.Laboratory long-term creep tests using epoxy resin and concrete as host matrix for FBG-GFRP sensors also clearly demonstrated that the influence of creep effect cannot be ignored for strain measurements if the host matrix has a creep potential and the developed correction model performed well to reduce measurement errors of such sensors in creep medium.

关键词： Fiber Bragg gratings(FBG)sensor strain transfer creep packaging layer epoxy resin concrete

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Nanomechanical Characteristics of Interfacial Transition Zone in Nano-Engineered Concrete

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Engineering 2022年第10期17卷 99-109页

作者： Xinyue Wang Sufen Dong Zhenming Li Baoguo Han jinping ou School of Civil Engineering Dalian University of TechnologyDalian 116024China School of Transportation and Logistics Dalian University of TechnologyDalian 116024China Department of Materials and Environment(Microlab) Faculty of Civil Engineering and GeoscienceDelft University of TechnologyDelft 2628 CNNetherlands

This study investigates the effects of nanofillers on the interfacial transition zone(ITZ)between aggregate and cement paste by using nanoindentation and statistical nanoindentation techniques.Moreover,the underlying mechanisms are revealed through micromechanical modeling.The nanoindentation results indicate that incorporating nanofillers increases the degree of hydration in the ITZ,reduces the content of micropores and low-density calcium silicate hydrate(LD C-S-H),and increases the content of highdensity C-S-H(HD C-S-H)and ultra high-density C-S-H(UHD C-S-H).In particular,a new phase,namely nano-core-induced low-density C-S-H(NCILD C-S-H),with a superior hardness of 2.50 GPa and an indentation modulus similar to those of HD C-S-H or UHD C-S-H was identified in this study.The modeling results revealed that the presence of nanofillers increased the packing density of LD CS-H and significantly enhanced the interaction(adhesion and friction)among the basic building blocks of C-S-H gels owing to the formation of nano-core-shell elements,thereby facilitating the formation of NCILD C-S-H and further improving the performance of the ITZ.This study provides insight into the effects of nano fillers on the ITZ in concrete at the nanoscale.

关键词： Concrete Nanofiller Interfacial transition zone Nanoindentation Micromechanical modeling Nano-core effect

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Exploring the impact of new particle formation events on PM_(2.5) pollution during winter in the Yangtze River Delta,China

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Journal of Environmental Sciences 2022年第1期34卷 75-83页

作者： jinping ou Qihou Hu Haoran Liu Shiqi Xu Zhuang Wang Xiangguang Ji Xinqi Wang Zhouqing Xie Hui Kang Institute of Physical Science and Information Technology Anhui UniversityHefei 230601China Key Lab of Environmental Optics and Technology Anhui Institute of Optics and Fine MechanicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China School of Environmental Science and Optoelectronic Technology University of Science and Technology of ChinaHefei 230026China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Institute of Polar Environment&Anhui Province Key Laboratory of Polar Environment and Global Change Department of Environment Science and TechnologyUniversity of Science and Technology of ChinaHefei 230026China

New particle formation(NPF)events are an increasingly interesting topic in air quality and climate science.In this study,the particle number size distributions,and the frequency of NPF events over Hefei were investigated from November 2018 to February 2019.The proportions of the nucleation mode,Aitken mode,and accumulation mode were 24.59%,53.10%,and 22.30%,respectively,which indicates the presence of abundant ultrafine particles in Hefei.Forty-six NPF events occurred during the observation days,accounting for 41.82%of the entire observation period.Moreover,the favorable meteorological conditions,potential precursor gases,and PM_(2.5)range of the NPF events were analyzed.Compared to non-NPF days,the NPF events preferentially occurred on days with lower relative humidity,higher wind speeds,and higher temperatures.When the PM_(2.5) was 15–20,70–80,and105–115μg/m^(3),the frequency of the NPF events was higher.Nucleation mode particles were positively related to atmospheric oxidation indicated by ozone when PM_(2.5) ranged from 15 to 20μg/m^(3),and related to gaseous precursors like SO_(2) and NO_(2) when PM_(2.5)was located at 70-80 and 105–115μg/m^(3).On pollution days,NPF events did not directly contribute to the increase in the PM_(2.5) in the daytime,however,NPF events would occur during the night and the growth of particulate matter contributes to the nighttime PM_(2.5) contents.This could lead to pollution that lasted into the next day.These findings are significant to the improvement of our understanding of the effects of aerosols on air quality.

关键词： New particle formation Aerosols PM_(2.5) Hefei Meteorological conditions

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Tailoring Anti-Impact Properties of Ultra-High Performance Concrete by Incorporating Functionalized Carbon Nanotubes

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Engineering 2022年第11期18卷 232-245页

作者： Jialiang Wang Sufen Dong Sze Dai Pang Xun Yu Baoguo Han jinping ou School of Civil Engineering Dalian University of TechnologyDalian 116024China School of Transportation and Logistics Dalian University of TechnologyDalian 116024China Department of Civil and Environmental Engineering National University of SingaporeSingapore 117576Singapore Department of Mechanical Engineering New York Institute of TechnologyNew YorkNY 11568USA

Replacing micro-reinforcing fibers with carbon nanotubes(CNTs)is beneficial for improving the impact properties of ultra-high performance concrete(UHPC);however,the weak wettability and dispersibility of CNTs and the weakly bonded interface between CNTs and UHPC limit their effectiveness as composites.Therefore,this study aims to enhance the reinforcement effect of CNTs on the impact properties of UHPC via functionalization.Unlike ordinary CNTs,functionalized CNTs with carboxyl or hydroxyl groups can break the Si-O-Ca-O-Si coordination bond in the C-S-H gel and form a new network in the UHPC matrix,effectively inhibiting the dislocation slip inside UHPC matrix.Furthermore,functionalized CNTs,particularly carboxyl-fu nctionalized CNTs,co ntrol the crystallization process and microscopic morphology of the hydration products,significantly decreasing and even eliminating the width of the aggregate-matrix interface transition zone of the UHPC.Moreover,the functionalized CNTs further decrease the attraction of the negatively charged silicate tetrahedron to Ca2+in the C-S-H gel,while modifying the pore structure(particularly the nanoscale pore structure)of UHPC,leading to the expansion of the intermediate CS-H layer.The changes in the microstructures of UHPC brought about by the functionalized CNTs significantly enhance its dynamic compressive strength,peak strain,impact toughness,and impact dissipation energy at strain rates of 200-800 s^(-1).Impact performance of UHPC containing a small amount of carboxyl-functionalized CNTs(especially the short ones)is generally better than that of UHPC containing hydroxyl-functionalized and ordinary CNTs;it is even superior to that of UHPC with a high steel fiber content.

关键词： Functionalized carbon nanotubes Concrete Anti-impact properties Reinforcing mechanisms

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Vertical distribution and temporal evolution of formaldehyde and glyoxal derived from MAX-DOAS observations:The indicative role of VOC sources

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Journal of Environmental Sciences 2022年第12期34卷 92-104页

作者： Qianqian Hong Cheng Liu Qihou Hu Yanli Zhang Chengzhi Xing jinping ou Wei Tan Haoran Liu Xiaoqing Huang Zhenfeng Wu School of Environment and Civil Engineering Jiangnan UniversityWuxi 214122China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Key Lab of Environmental Optics&Technology Anhui Institute of Optics and Fine MechanicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China Department of Precision Machinery and Precision Instrumentation University of Science and Technology of ChinaHefei 230026China Anhui Province Key Laboratory of Polar Environment and Global Change University of Science and Technology of ChinaHefei 230026China Guangdong Key Laboratory of Environmental Protection and Resources Utilization State Key Laboratory of Organic GeochemistryGuangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Guangdong-Hongkong-Macao Joint Laboratory of Collaborative Innovation for Environmental Quality Guangzhou 510632China Institute of Physical Science and Information Technology Anhui UniversityHefei 230601China

Formaldehyde(HCHO)and glyoxal(CHOCHO)are important oxidization intermediates of most volatile organic compounds(VOCs),but their vertical evolution in urban areas is not well understood.Vertical profiles of HCHO,CHOCHO,and nitrogen dioxide(NO_(2))were retrieved from ground-based Multi-Axis Differential Optical Absorption Spectroscopy(MAXDOAS)observations in Hefei,China.HCHO and CHOCHO vertical profiles prefer to occur at higher altitudes compared to NO_(2),which might be caused by the photochemistry-oxidation of longer-lived VOCs at higher altitudes.Monthly means of HCHO concentrations were higher in summer,while enhanced amounts of NO_(2)were mainly observed in winter.CHOCHO exhibited a hump-like seasonal variation,with higher monthly-averaged values not only occurred in warm months(July-August)but also in cold months(November-December).Peak values mainly occurred during noon for HCHO but emerged in the morning for CHOCHO and NO_(2),suggesting that HCHO is stronger link to photochemistry than CHOCHO.We further use the glyoxal to formaldehyde ratio(GFR)to investigate the VOC sources at different altitudes.The lowest GFR value is almost found in the altitude from 0.2 to 0.4 km,and then rises rapidly as the altitude increases.The GFR results indicate that the largest contributor of the precursor VOC is biogenic VOCs at lower altitudes,while at higher altitudes is anthropogenic VOCs.our findings provide a lot more insight into VOC sources at vertical direction,but more verification is recommended to be done in the future.

关键词： Formaldehyde Glyoxal MAX-DOAS Vertical distribution VOC

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BEHAVIOR OF AIR-ENTRAINED CONCRETE AFTER FREEZE-THAW CYCLES

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Acta Mechanica Solida Sinica 2009年第3期22卷 261-266页

作者： Huaishuai Shang Yupu Song jinping ou State Key Laboratory of Structural Analysis for Industrial Equipment DaIian University of Technology Dalian 116024 China Shandong Provincial Academy of Building Research Jinan 250031 China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

The experimental study of air-entrained concrete specimens subjected to different cycles of freeze-thaw was completed. The dynamic modulus of elasticity, weight loss, the cubic compressive strength, compressive strength, tensile strength and cleavage strength of air-entrained concrete were measured after 0, 100, 200, 300, 400 cycles of freeze-thaw. The experimental results showed that the dynamic modulus of elasticity and strength decreased as the freeze-thaw was repeated. The influences of freeze-thaw cycles on the mechanical properties, the dynamic modulus of elasticity and weight loss were analyzed according to the experimental results. It can serve as a reference for the maintenance, design and the life prediction of dams, hydraulic structures, offshore structures, concrete roads and bridges in northern cold regions.

关键词： air-entrained concrete freeze-thaw cycles mechanical properties the dynamic mod-ulus of elasticity weight loss

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The typhoon effect on the aerodynamic performance of a floating offshore wind turbine

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Journal of Ocean Engineering and Science 2017年第4期2卷 279-287页

作者： Zhe Ma Wei Li Nianxin Ren jinping ou Deepwater Engineering Research Center Dalian University of TechnologyDalian 116024China State Key Laboratory of Coast and Offshore Engineering Dalian University of TechnologyDalian 116024China Offshore Wind Power R&D Center Hydrochina Huadong Engineering CorporationHangzhou 310014China Beijing’s Key Laboratory of Structural Wind Engineering and Urban Wind Environment Beijing Jiaotong UniversityBeijing100044China

The wind energy resource is considerably rich in the deep water of China South Sea,where wind farms have to face the challenge of extreme typhoon events.In this work,the typhoon effect on the aerodynamic performance of the 5MW OC3-Hywind floating offshore wind turbine(FOWT)system has been investigated,based on the Aero-Hydro-Servo-Elastic FAST code.First,considering the full field observation data of typhoon“Damrey”is a long duration process with significant turbulence and high wind speed,so one 3-h representative truncated typhoon wind speed time history has been selected.Second,the effects of both the(variable-speed and collective-pitch)control system of NREL 5 MW wind turbine and the motion of the floating platform on the blade aerodynamic performance of the FOWT system during the representative typhoon time history has been investigated,based on blade element momentum(BEM)theory(coupled with potential theory for the calculation of the hydrodynamic loads of the Spar platform).Finally,the effects of different wind turbine control strategies,control parameter(KP-KI)combinations,wave heights and parked modes on the rotor aerodynamic responses of the FOWT system have been clarified.The extreme typhoon event can result in considerably large extreme responses of the rotor thrust and the generated power due to the possible blade pitch angle error phenomenon.One active-parked strategy has been proposed for reducing the maximum aerodynamic responses of the FOWT system during extreme typhoon events.

关键词： Typhoon Floating offshore wind turbine Aerodynamic performance Control system FAST

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Coupling of Peridynamics and Numerical Substructure Method for Modeling Structures with Local Discontinuities

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Computer Modeling in Engineering & Sciences 2019年第9期120卷 739-757页

作者： Baoyin Sun Shaofan Li Quan Gu jinping ou Faculty of Infrastructure Engineering Dalian University of TechnologyDalian116024China School of Architecture and Civil Engineering Xiamen UniversityXiamen361005China Department of Civil and Environmental Engineering University of CaliforniaBerkeleyCA 94720USA

Peridynamics(PD)is a widely used theory to simulate discontinuities,but its application in real-world structural problems is somewhat limited due to the relatively low-efficiency.The numerical substructure method(NSM)presented by the authors and co-workers provides an efficient approach for modeling structures with local nonlinearities,which is usually restricted in problems of continuum mechanics.In this paper,an approach is presented to couple the PD theory with the NSM for modeling structures with local discontinuities,taking advantage of the powerful capability of the PD for discontinuities simulation and high computational efficiency of the NSM.The structure is simulated using liner elastic finite element(FE)model while the local cracking regions are isolated and simulated using a PD substructure model.A force corrector calculated from the PD model is applied on the FE model to consider the effect of discontinuities.The PD is integrated in the substructure model using interface elements with embedded PD nodes.The equations of motions of both the NSM system and the PD substructure are solved using the central difference method.Three examples of two-dimensional(2D)concrete cantilever beams under the concentrated force are investigated to verify the proposed coupling approach.

关键词： Peridynamic numerical substructure method local discontinuities crack

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