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Structural performance of a façade precast concrete sandwich panel enabled by a bar-type basalt fiber-reinforced

《结构与土木工程前沿（英文）》 2023年 第17卷 第1期   页码 122-137 doi: 10.1007/s11709-022-0894-1

摘要： In this study, a novel diagonally inserted bar-type basalt fiber reinforced polymer (BFRP) connector was proposed, aiming to achieve both construction convenience and partially composite behavior in precast concrete sandwich panels (PCSPs). First, pull-out tests were conducted to evaluate the anchoring performance of the connector in concrete after exposure to different temperatures. Thereafter, direct shear tests were conducted to investigate the shear performance of the connector. After the test on the individual performance of the connector, five façade PCSP specimens with the bar-type BFRP connector were fabricated, and the out-of-plane flexural performance was tested under a uniformly distributed load. The investigating parameters included the panel length, opening condition, and boundary condition. The results obtained in this study primarily indicated that 1) the bar-type BFRP connector can achieve a reliable anchorage system in concrete; 2) the bar-type BFRP connector can offer sufficient stiffness and capacity to achieve a partially composite PCSP; 3) the boundary condition of the panel considerably influenced the out-of-plane flexural performance and composite action of the investigated façade PCSP.

关键词： precast concrete sandwich panel     basalt fiber reinforced polymer     pull-out performance     shear performance     out-of-plane flexural performance    

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Simplified theoretical analysis and numerical study on the dynamic behavior of FCP under blast loads

Chunfeng ZHAO, Xin YE, Avinash GAUTAM, Xin LU, Y. L. MO

《结构与土木工程前沿（英文）》 2020年 第14卷 第4期   页码 983-997 doi: 10.1007/s11709-020-0633-4

摘要： Precast concrete structures have developed rapidly in the last decades due to the advantages of better quality, non-pollution and fast construction with respect to conventional cast-in-place structures. In the present study, a theoretical model and nonlinear 3D model are developed and established to assess the dynamic behavior of precast concrete slabs under blast load. At first, the 3D model is validated by an experiment performed by other researchers. The verified model is adopted to investigate the blast performance of fabricated concrete panels (FCPs) in terms of parameters of the explosive charge, panel thickness, and reinforcement ratio. Finally, a simplified theoretical model of the FCP under blast load is developed to predict the maximum deflection. It is indicated that the theoretical model can precisely predict the maximum displacement of FCP under blast loads. The results show that the failure modes of the panels varied from bending failure to shear failure with the mass of TNT increasing. The thickness of the panel, reinforcement ratio, and explosive charges have significant effects on the anti-blast capacity of the FCPs.

关键词： precast structure     fabricated concrete panel     blast resistance     theory model     empirical equation    

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Strengthening of reinforced concrete beams using fiber-reinforced cementitious matrix systems fabricated

《结构与土木工程前沿（英文）》   页码 1100-1116 doi: 10.1007/s11709-023-0967-9

摘要： The performance of a new fiber-reinforced cementitious matrix (FRCM) system developed using custom-designed mortar and fabrics is investigated in this study. The behavior of this system is evaluated in terms of both the flexural and shear strengthening of reinforced concrete beams. Eight beams are designed to assess the effectiveness of the FRCM system in terms of flexural strengthening, and four specimens are designed to investigate their shear behavior. The parameters investigated for flexural strengthening are the number of layers, span/depth ratio, and the strengthening method. Unlike previous studies, custom fabrics with similar axial stiffness are used in all strengthening methods in this study. In the shear-strengthened specimens, the effects of the span/depth ratio and strengthening system type (fiber-reinforced polymer (FRP) or FRCM) are investigated. The proposed FRCM system exhibits desirable flexural and shear strengthening for enhancing the load capacity, provides sufficient bonding with the substrate, and prevents premature failure modes. Considering the similar axial stiffness of fabrics used in both FRCM and FRP systems and the higher load capacity of specimens strengthened by the former, cement-based mortar performs better than epoxy.

关键词： fiber-reinforced cementitious matrix     flexural strengthening     shear strengthening     carbon fiber-reinforced polymer     shear span    

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Effectiveness of state incentives for promoting wind energy: A panel data examination

Deepak SANGROYA,Jogendra NAYAK

《能源前沿（英文）》 2015年 第9卷 第3期   页码 247-258 doi: 10.1007/s11708-015-0364-8

摘要： Over the last decade, India has started to concentrate earnestly on renewable energy. The Indian government, as well as different state governments, are adopting policy instruments such as feed in tariff, captive consumption, renewable purchase obligation and generation based incentive etc. aimed at renewable energy development. This paper evaluates the effectiveness of state level incentives for the development of wind energy in India. Fixed effect panel data modelling technique of econometric analysis is used to analyse the data of 26 Indian states in 11 years. The results show that feed in tariff and captive consumption are the significant predictors of wind energy development. However, renewable purchase obligation does not affect wind energy significantly.

关键词： India     wind energy development     state incentives     econometric analysis     panel data    

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GO-modified flexible polymer nanocomposites fabricated via 3D stereolithography

Chi Him Alpha Tsang, Adilet Zhakeyev, Dennis Y.C. Leung, Jin Xuan

《化学科学与工程前沿（英文）》 2019年 第13卷 第4期   页码 736-743 doi: 10.1007/s11705-019-1836-x

摘要： Graphene oxide (GO) induced enhancement of elastomer properties showed a great deal of potential in recent years, but it is still limited by the barrier of the complicated synthesis processes. Stereolithography (SLA), used in fabrication of thermosets and very recently in “flexible” polymers with elastomeric properties, presents itself as simple and user-friendly method for integration of GO into elastomers. In this work, it was first time demonstrated that GO loadings can be incorporated into commercial flexible photopolymer resins to successfully fabricate GO/elastomer nanocomposites via readily accessible, consumer-oriented SLA printer. The material properties of the resulting polymer was characterized and tested. The mechanical strength, stiffness, and the elongation of the resulting polymer decreased with the addition of GO. The thermal properties were also adversely affected upon the increase in the GO content based on differential scanning calorimetry and thermogravimetric analysis results. It was proposed that the GO agglomerates within the 3D printed composites, can result in significant change in both mechanical and thermal properties of the resulting nanocomposites. This study demonstrated the possibility for the development of the GO/elastomer nanocomposites after the optimization of the GO/“flexible” photoreactive resin formulation for SLA with suitable annealing process of the composite in future.

关键词： graphene oxide     polymer     flexible     3D printing     stereolithography    

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On braced trapezoidal corrugated steel shear panels: An experimental and numerical study

《结构与土木工程前沿（英文）》 2023年 第17卷 第3期   页码 396-410 doi: 10.1007/s11709-023-0934-5

摘要： In this study, a new system consisting of a combination of braces and steel infill panels called the braced corrugated steel shear panel (BCSSP) is presented. To obtain the hysteretic behavior of the proposed system, the quasi-static cyclic performances of two experimental specimens were first evaluated. The finite element modeling method was then verified based on the obtained experimental results. Additional numerical evaluations were carried out to investigate the effects of different parameters on the system. Subsequently, a relationship was established to estimate the buckling shear strength of the system without considering residual stresses. The results obtained from the parametric study indicate that the corrugated steel shear panel (CSSP) with the specifications of a = 30 mm, t = 2 mm, and θ = 90° had the highest energy dissipation capacity and ultimate strength while the CSSP with the specifications of a = 30 mm, t = 2 mm, and θ = 30° had the highest initial stiffness. It can thus be concluded that the latter CSSP has the best structural performance and that increasing the number of corrugations, corrugation angle, and plate thickness and decreasing the sub-panel width generally enhance the performance of CSSPs in terms of the stability of their hysteretic behaviors.

关键词： trapezoidal corrugated plate     steel shear panel     braced steel shear panel     experimental study     buckling resistance.    

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农作物秸秆人造板的研究

周定国

《中国工程科学》 2009年 第11卷 第10期   页码 115-121

摘要：

发展农作物秸秆人造板产业对于保护森林资源和人类环境，解决我国木材原料供应不足的矛盾具有重要的现实意义。近年来，科技人员在农作物秸秆人造板基础研究、产品开发和工业化应用方面做了大量的研究工作。文章介绍了笔者及所在团队在秸秆原料特性和秸秆板制造工艺方面的最新研究成果。

关键词： 农作物秸秆     人造板     研究前景    

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Seismic performance of fabricated continuous girder bridge with grouting sleeve-prestressed tendon composite

《结构与土木工程前沿（英文）》   页码 827-854 doi: 10.1007/s11709-023-0954-1

摘要： The seismic performance of a fully fabricated bridge is a key factor limiting its application. In this study, a fiber element model of a fabricated concrete pier with grouting sleeve-prestressed tendon composite connections was built and verified. A numerical analysis of three types of continuous girder bridges was conducted with different piers: a cast-in-place reinforced concrete pier, a grouting sleeve-fabricated pier, and a grouting sleeve-prestressed tendon composite fabricated pier. Furthermore, the seismic performance of the composite fabricated pier was investigated. The results show that the OpenSees fiber element model can successfully simulate the hysteresis behavior and failure mode of the grouted sleeve-fabricated pier. Under traditional non-near-fault ground motions, the pier top displacements of the grouting sleeve-fabricated pier and the composite fabricated pier were less than those of the cast-in-place reinforced concrete pier. The composite fabricated pier had a good self-centering capability. In addition, the plastic hinge zones of the grouting sleeve-fabricated pier and the composite fabricated pier shifted to the joint seam and upper edge of the grouting sleeve, respectively. The composite fabricated pier with optimal design parameters has good seismic performance and can be applied in high-intensity seismic areas; however, the influence of pile-soil interaction on its seismic performance should not be ignored.

关键词： seismic performance     continuous girder bridge     grouting sleeve-prestressed tendon composite connections     grouted sleeve connection     design parameters    

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Orientation effect of electropolishing characteristics of 316L stainless steel fabricated by laser powder

《机械工程前沿（英文）》 2021年 第16卷 第3期   页码 580-592 doi: 10.1007/s11465-021-0633-7

摘要： 3D metal printing process has attracted increasing attention in recent years due to advantages, such as flexibility and rapid prototyping. This study aims to investigate the orientation effect of electropolishing characteristics on different surfaces of 316L stainless steel fabricated by laser powder bed fusion (L-PBF), considering that the rough surface of 3D printed parts is a key factor limiting its applications in the industry. The electropolishing characteristics on the different surfaces corresponding to the building orientation in selective laser melting are studied. Experimental results show that electrolyte temperature has critical importance on the electropolishing, especially for the vertical direction to the layering plane. The finish of electropolished surfaces is affected by the defects generated during L-PBF process. Thus, the electropolished vertical surface has higher surface roughness Sa than the horizontal surface. The X-ray photoelectron spectroscopy spectra show that the electropolished horizontal surface has higher Cr/Fe element ratio than the vertical surface. The electropolished horizontal surface presents higher corrosion resistance than the vertical surface by measuring the anodic polarization curves and fitting the equivalent circuit of experimental electrochemical impedance spectroscopy.

关键词： electropolishing     laser powder bed fusion     316L stainless steel     corrosion resistance     microstructure    

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The development of ultralightweight expanded perlite-based thermal insulation panel using alkali activator

Damla Nur ÇELİK; Gökhan DURMUŞ

《结构与土木工程前沿（英文）》 2022年 第16卷 第11期   页码 1486-1499 doi: 10.1007/s11709-022-0881-6

摘要： The International Energy Agency (IEA) states that global energy consumption will increase by 53% by 2030. Turkey has 70% of the world’s perlite reserves, and in order to reduce energy consumption a thermal insulation panel was developed in Turkey using different particle sizes of expanded perlite (EP). In this study, 0–1.18 mm (powder) and 0–3 mm (granular) EP particle sizes were selected, since they have the lowest thermal conductivity coefficients among all the particle sizes. In addition, an alkali activator solution was used as a binder in the mixtures. The alkaline activator solution was obtained by mixing sodium hydroxide solution (6, 8, 10, and 12 mol·L−1) and sodium silicate (Module 3) at the different ratios of Na2SiO3 to NaOH of 1, 1.5, 2, and 2.5. This study aimed to experimentally determine the optimum binder and distribution ratio of EP, with the lowest coefficient of thermal conductivity and the lowest density. The lowest thermal conductivity and the lowest density were determined as 0.04919 W·m−1·K−1 and 133.267 kg/m3, respectively, in the sample prepared with 83.33% powder-size EP, 6 mol·L−1 sodium hydroxide solution, and ratio of Na2SiO3 to NaOH of 1.5. The density, thermal conductivity, and compressive strength of the sample showed the same trends of behavior when the Na2SiO3 to NaOH ratio was increased. In addition, the highest compressive strength was measured in 12 mol·L−1 NaOH concentration regardless of particle size. In conclusion, the study predicts that the EP-based thermal insulation panel can be used as an insulation material in the construction industry according to the TS825 Thermal Insulation Standard.

关键词： expanded perlite     alkali activator     thermal insulation panel     thermal conductivity    

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Effect of strata restraint on seismic performance of prefabricated sidewall joints in fabricated subway

《结构与土木工程前沿（英文）》 2023年 第17卷 第5期   页码 763-779 doi: 10.1007/s11709-023-0917-6

摘要： A disadvantage of the conventional quasi-static test method is that it does not consider the soil restraint effect. A new method to test the seismic performance of prefabricated specimens for underground assembled structures is proposed, which can realistically reflect the strata restraint effect on the underground structure. Laboratory work combined with finite element (FE) analysis is performed in this study. Three full-scale sidewall specimens with different joint forms are designed and fabricated. Indices related to the seismic performance and damage modes are analyzed comprehensively to reveal the mechanism of the strata restraint effect on the prefabricated sidewall components. Test results show that the strata restraint effect effectively improves the energy dissipation capacity, load-bearing capacity, and the recoverability of the internal deformation of the precast sidewall components. However, the strata restraint effect reduces the ductility of the precast sidewall components and aggravates the shear and bending deformations in the core region of the connection joints. Additionally, the strata restraint effect significantly affects the seismic performance and damage mode of the prefabricated sidewall components. An FE model that can be used to conduct a seismic performance study of prefabricated specimens for underground assembled structures is proposed, and its feasibility is verified via comparison with test data.

关键词： underground structures     precast sidewall specimen     seismic test method     bearing capacity     energy dissipation capacity     plastic deformation    

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Lung function and air pollution exposure in adults with asthma in Beijing: a 2-year longitudinal panel

《医学前沿（英文）》 2022年 第16卷 第4期   页码 574-583 doi: 10.1007/s11684-021-0882-1

摘要： The effect of air pollution on the lung function of adults with asthma remains unclear to date. This study followed 112 patients with asthma at 3-month intervals for 2 years. The pollutant exposure of the participants was estimated using the inverse distance weight method. The participants were divided into three groups according to their lung function level at every visit. A linear mixed-effect model was applied to predict the change in lung function with each unit change in pollution concentration. Exposure to carbon monoxide (CO) and particles less than 2.5 micrometers in diameter (PM2.5) was negatively associated with large airway function in participants. In the severe group, exposure to chronic sulfur dioxide (SO2) was negatively associated with post-bronchodilator forced expiratory flow at 50%, between 25% and 75% of vital capacity % predicted (change of 95% CI per unit: −0.34 (−0.55, −0.12), −0.24 (−0.44, −0.03), respectively). In the mild group, the effect of SO2 on the small airways was similar to that in the severe group, and it was negatively associated with large airway function. Exposure to CO and PM2.5 was negatively associated with the large airway function of adults with asthma. The negative effects of SO2 were more evident and widely observed in adults with severe and mild asthma than in adults with moderate asthma. Patients with asthma react differently to air pollutants as evidenced by their lung function levels.

关键词： lung function     asthma     air pollution     adult    

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Spillover effect of environmental investment: evidence from panel data at provincial level in China

Qunhui LIN, Guanyi CHEN, Wencui DU, Haipeng NIU

《环境科学与工程前沿（英文）》 2012年 第6卷 第3期   页码 412-420 doi: 10.1007/s11783-012-0392-0

摘要： This paper considers pollution density as a function of environmental investment. The higher environmental investment, the lower pollution density. The lower the pollution density is the higher production technology becomes. This is called the spillover effect. We collected China’s panel data at the provincial level from 2005 to 2009, and tested the spillover effect of environmental investment. This paper finds that the environmental investment influenced production technology positively. There is a significant positive relation between government expenditure and spillover effect.

关键词： environmental investment     spillover effect     endogenous growth    

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A comprehensive simulator for assessing the reliability of a photovoltaic panel peak power tracking system

Nabil KAHOUL,Mourad HOUABES,Ammar NEÇAIBIA

《能源前沿（英文）》 2015年 第9卷 第2期   页码 170-179 doi: 10.1007/s11708-015-0353-y

摘要： When designing a maximum power point tracking (MPPT) algorithm, it is often difficult to correctly predict, before field testing, the behavior of this MPPT under varying solar irradiation on photovoltaic (PV) panels. A solution to this problem is to design a maximum power point trackers simulator of a PV system used to test MPPT algorithms. This simulator must have the same role as the MPPT card of the PV panel and thus will fully emulate the response of a real MPPT card of the PV panel. Therefore, it is a good substitute to help to test the peak power trackers of the PV system in the laboratory. This paper describes a simple peak power trackers simulator of the PV system which has a short response time thus, can be used to test MPPT algorithms under very rapid variation condition. The obtained results and the theoretical operation confirm the reliability and the superior performance of the proposed model.

关键词： photovoltaic module     DC-DC converter     design     maximum power point tracking (MPPT) card     microprocessor    

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Structural dimension optimization and mechanical response analysis of fabricated honeycomb plastic pavement

Zixuan CHEN; Tao LIU; Xiao MA; Hanyu TANG; Jianyou HUANG; Jianzhong PEI

《结构与土木工程前沿（英文）》 2022年 第16卷 第7期   页码 896-908 doi: 10.1007/s11709-022-0856-7

摘要： Because of favorable mechanical properties, deformation resistance and being conducive to environmental protection, honeycomb fabricated plastic pavement slabs are highly recommended these years. At present, most studies focus on the performance of plastic materials, however, the dimension optimization of fabricated plastic pavement slab is rarely mentioned. In this paper, an optimized geometry of the honeycomb pavement slab was determined through finite element analysis. Mechanical response of honeycomb slabs with different internal dimensions and external dimensions were explored. Several dimension factors were taken into consideration including the side length, rib thickness, the thickness of both top and bottom slabs of honeycomb structure and the length, the width and the thickness of the fabricated plastic slab. The results showed that honeycomb pavement slab with 6 cm bottom slab, 12 cm top slab,18 cm side length and 6 cm rib thickness is recommended, additionally, an external dimension of 4 m × 4 m × 0.45 m is suggested. Then, the mechanical responses of this optimized fabricated plastic slab were further investigated. Significance of different influencing factors, including wheel load, elastic modulus of plastic material, base layer thickness, soil foundation modulus and base layer modulus were ranked.

关键词： honeycomb structure     plastic pavement     dimension optimization     mechanical response     factor significance    

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标题 作者 时间 类型 操作

Structural performance of a façade precast concrete sandwich panel enabled by a bar-type basalt fiber-reinforced

期刊论文

Simplified theoretical analysis and numerical study on the dynamic behavior of FCP under blast loads

Chunfeng ZHAO, Xin YE, Avinash GAUTAM, Xin LU, Y. L. MO

期刊论文

Strengthening of reinforced concrete beams using fiber-reinforced cementitious matrix systems fabricated

期刊论文

Effectiveness of state incentives for promoting wind energy: A panel data examination

Deepak SANGROYA,Jogendra NAYAK

期刊论文

GO-modified flexible polymer nanocomposites fabricated via 3D stereolithography

Chi Him Alpha Tsang, Adilet Zhakeyev, Dennis Y.C. Leung, Jin Xuan

期刊论文

On braced trapezoidal corrugated steel shear panels: An experimental and numerical study

期刊论文

农作物秸秆人造板的研究

周定国

期刊论文

Seismic performance of fabricated continuous girder bridge with grouting sleeve-prestressed tendon composite

期刊论文

Orientation effect of electropolishing characteristics of 316L stainless steel fabricated by laser powder

期刊论文

The development of ultralightweight expanded perlite-based thermal insulation panel using alkali activator

Damla Nur ÇELİK; Gökhan DURMUŞ

期刊论文

Effect of strata restraint on seismic performance of prefabricated sidewall joints in fabricated subway

期刊论文

Lung function and air pollution exposure in adults with asthma in Beijing: a 2-year longitudinal panel

期刊论文

Spillover effect of environmental investment: evidence from panel data at provincial level in China

Qunhui LIN, Guanyi CHEN, Wencui DU, Haipeng NIU

期刊论文

A comprehensive simulator for assessing the reliability of a photovoltaic panel peak power tracking system

Nabil KAHOUL,Mourad HOUABES,Ammar NEÇAIBIA

期刊论文

Structural dimension optimization and mechanical response analysis of fabricated honeycomb plastic pavement

Zixuan CHEN; Tao LIU; Xiao MA; Hanyu TANG; Jianyou HUANG; Jianzhong PEI

期刊论文