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Efficient Two-Stage Strain/Temperature Measurement Method for Botda System Based on Bayesian Uncertainty Quantification

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SSRN 2022年

作者： Meng, Xianghao Zhang, Dongyu Li, Hui Huang, Yong Key Lab of Structures Dynamic Behavior and Control The Ministry of Education School of Civil Engineering Harbin Institute of Technology Harbin China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin China

Brillouin optical time-domain analysis (BOTDA) is an efficient distributed structural strain/temperature measurement technology by identifying the Brillouin frequency (BF) of the fiber. The original BF identification method involves gradually tuning the scanning frequency of the probe laser light, which is time-consuming. To improve the sensing efficiency of BOTDA, a novel two-stage strain/temperature measurement method is proposed based on Bayesian uncertainty quantification. The method uses the information of a small amount of wide range frequency scanning data in the 1st stage to guide a concentrated scanning of the frequency points in the 2nd stage by employing transitional Markov chain Monte Carlo (TMCMC) algorithm. The second-stage scanning strategy based on Bayesian uncertainty quantification ensures the high confidence for BF identification, so that the number of required scanning points can be significantly reduced without sacrificing the measurement accuracy. Finally, the efficacy of the proposed method is verified using numerical and experimental data. © 2022, The Authors. All rights reserved.

关键词： Uncertainty analysis

Static and Fatigue Performances of Clip Anchoring System For Frp Rod Used in Cable

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SSRN 2024年

作者： Xian, Guijun Niu, Yanzhao Tian, Jingwei Li, Chenggao Yue, Qingrui Guo, Rui Key Lab of Structures Dynamic Behavior and Control Harbin Institute of Technology Ministry of Education Heilongjiang Harbin150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Heilongjiang Harbin150090 China Research Institute of Urbanization and Urban Safety School of Civil and Resource Engineering University of Science and Technology Beijing Beijing China

To obtain the static and fatigue performances and provide the design parameters of FRP rod for the application in cable structures. In the present paper, the design and preparation method of steel clip anchor, steel clip anchor with aluminum sleeve and adhesive interlayer are presented. The effect of taper difference, preload and anchor type on static and fatigue performances is studied by tensile and fatigue test, and the optimal design and application parameters of anchor are obtained. The results show that the peak shear stress of the rod at the front end of anchor can be reduced effectively by setting 0.1 ° taper difference, and the bearing capacity of anchor is increased by 5.3%-40.7% compared with 0 ° and 0.2 ° taper difference. The slippage of anchor can be reduced effectively with the increase of preload, which improves the critical slippage load of anchor. In addition, the stress concentration of rod inside the anchor can be reduced with the added of low modulus adhesive layer between steel clip and rod, which reduces the sensitivity of tensile performances to taper difference and delays the fatigue damage accumulation process of rod inside the anchor, the anchoring efficiency and fatigue resistance increases by 10.9% and 61.4% compared with steel clip anchor, respectively. © 2024, The Authors. All rights reserved.

关键词： Fatigue testing

An Adaptive Substructure-Based Model Order Reduction Method for Nonlinear Seismic Analysis in OpenSees

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Computer Modeling in Engineering & Sciences 2020年第7期124卷 79-106页

作者： Jian Wang Ming Fang Hui Li Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of TechnologyHarbin150090China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of TechnologyHarbin150090China College of Shipbuilding Engineering Harbin Engineering UniversityHarbin150001China.

Structural components may enter an initial-elastic state,a plastic-hardening state and a residual-elastic state during strong seismic *** the residual-elastic state,structural components keep in an unloading/reloading stage that is dominated by a tangent stiffness,thus structural components remain residual deformations but behave in an elastic *** has a great potential to make model order reduction for such structural components using the tangent-stiffness-based vibration modes as a reduced order *** this paper,an adaptive substructure-based model order reduction method is developed to perform nonlinear seismic analysis for structures that have a priori unknown damage *** method is able to generate time-varying substructures and make nonlinear model order reduction for substructures in the residual-elastic *** finite element program OpenSees has been extended to provide the adaptive substructure-based nonlinear seismic *** the low level of OpenSees framework,a new abstract layer is created to represent the time-varying substructures and implement the modeling process of *** the high level of OpenSees framework,a new transient analysis class is created to implement the solving process of substructure-based governing *** with the conventional time step integration method,the adaptive substructure-based model order reduction method can yield comparative results with a higher computational efficiency.

关键词： Adaptive substructure modeling model order reduction nonlinear seismic

The Deformation of C–S–H Gel and its Link with Length Change of Cement Pastes on Drying and Resaturation

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SSRN 2023年

作者： Zhang, Xiaoyu Qiao, Jing Feng, Jingjing Xu, Shilang Zhou, Chunsheng Zeng, Qiang Key Lab of Structures Dynamic Behavior and Control Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China College of Water Conservancy and Civil Engineering Shandong Agricultural University Taian271018 China College of Civil Engineering and Architecture Zhejiang University Hangzhou310058 China

Drying shrinkage of cement pastes (CPs) facilitating superficial cracking deserves primary concern when handling durability performance. In order to further clarify shrinkage mechanism, the changes of mass, length and pore water allocation of two mature CPs were monitored principally through non-destructive low-field NMR relaxation technique. Experimental results revealed that, heat treatment under hot water slightly coarsens the pore structure of CPs through modifying the morphology of C-S-H gel, but reduces shrinkage during first drying remarkably. During drying at 80% RH, although both interlayer and gel pores are saturated, they loss their water progressively at reducing rates. At the expense of reducing interlayer space, the contraction of gel pores is partly and even entirely compensated. When drying at lower 43% RH, interlayer pores still saturated are compacted more significantly with reducing size and volume. The compaction of interlayer pores is at the micro-structural origin and dominates drying shrinkage of CPs. © 2023, The Authors. All rights reserved.

关键词： Drying

Evaluating Progressive Collapse with Automatic Check Vba Programming and Identifying Optimal Performance Bracing of Systems

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SSRN 2024年

作者： Bigonah, Mohammad Ali, Barham Haidar Rashed, Parya Li, Shuang Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Faculty of Engineering Civil Engineering Department Tishk International University Erbil Iraq School of Civil Engineering Iran University of Science and Technology Narmak Tehran16765-163 Iran

Braced frames are among the most effective systems for resisting progressive collapse;however, determining the optimal bracing system remains a challenge. In this study, several bracing systems were evaluated using a flowchart that satisfied the regulations UFC (chapter 4). VBA programming tools were employed to facilitate the evaluation process. The utilization of the control process and automated VBA programming proved beneficial in the inspection of plastic hinges and ensuring compliance with UFC regulation. The behaviour of four types of braced frames, including concentrically and eccentrically braced frames (CBF and EBF), was investigated under three scenarios involving member removal. The results demonstrated that the inverted V-braced CBF and EBF systems exhibited superior performance by minimizing vertical displacement and redistributing forces on the remaining connected members. In this scenario, despite experiencing significant vertical displacement, lower global forces were observed in all beams and columns. However, the frame without any bracing system failed to meet the regulatory standards, as determined by the control flowchart. Conversely, the remaining structural systems performed exceptionally well. © 2024, The Authors. All rights reserved.

关键词： Compliance control

Effects of Various Connectors on the Whole-Life-Cycle Energy Consumption of Sandwich Wall Panels in Five Thermal Zones of china

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SSRN 2022年

作者： Dong, Xianzhang Lu, Yiming Xiao, Huigang Liao, Juan School of Civil Engineering Harbin Institute of Technology Harbin150090 China Key Lab of Structures Dynamic Behavior and Control Ministry of Education Harbin Institute of Technology Harbin150090 China China Construction Second Engineering Bureau. Ltd 100160 China

Connectors are not only an important mechanical component of sandwich wall panels (SWPs), but they also contribute to SWP energy loss because they penetrate thermal insulation layers. Reducing the energy consumption (EC) generated by connectors is critical for improving the energy-saving efficiency of SWPs throughout their life cycle. The mechanical and thermal parameters of connectors, structural layers, and insulation layers all have a coupling effect on the EC of connectors in the SWPs studied in this study. First, a connector diameter calculation model and a three-dimensional finite element (3-DFE) model were developed to investigate the mechanism of various connectors' effects on the thermal performance (TP) of SWPs with different structural and insulation layers. It was discovered that increasing the connector shear strength could reduce energy loss by reducing the connector size, and connector energy loss could also be improved by lowering the connector thermal conductivity and increasing the thermal resistance of the structural layers. Then, based on TP, a life cycle assessment (LCA) model was developed. Using five thermal zones in china as research subjects, it was discovered that the effects of connectors on the whole-life-cycle EC of SWPs depend on the value of degree days (DD). The connector manufacturing EC dominated the whole-life-cycle EC in an area with a low DD value. Reduced thermal conductivities of connectors, structural layers, and insulation layers could significantly improve the effects of connectors on the whole-life-cycle EC of SWPs in an area with a high value of DD. These findings are critical for the development of effective SWPs. © 2022, The Authors. All rights reserved.

关键词： Energy utilization

Pretreated Lightweight Aggregates for Self-Healing Concrete Exposed to Calcium Hydroxide-Rich Sewage

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SSRN 2022年

作者： Li, Jinglu Guan, Xinchun Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Key Lab of Structures Dynamic Behavior and Control The Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China

Wastewater concrete pipes are prone to cracking, causing deterioration in durability. As an acidic effluent treatment agent, calcium hydroxide is widely applied in sewage pipes. Based on the above background, this study investigated the self-healing behavior of the mortar containing pretreated lightweight aggregates in calcium hydroxide-rich sewage. Ceramsites were previously treated by impregnating with sodium silicate and encapsulating. Then, the mortar mixed with pretreated ceramsites was pre-cracked and exposed to water, Ca(OH)2 solution and Ca(OH)2 solution/dry cycles. The healing efficiency was evaluated by mechanical test, water absorption and crack visual observation. Results showed that the mortar exposed to Ca(OH)2 solution/dry cycles exhibited the most dominant healing efficiency. After healing for 30 days, the recovery rate of strength and reduction rate of sorptivity coefficient were 65% and 68%, respectively. The closure rate of the crack of 0-250 μm in width exceeded 80%. The area healing rates of the crack with an initial width of 200 μm reached up to 100%, 89% and 78%, respectively. Moreover, SEM and EDS indicated that healing products were mainly C-S-H gel and calcite. The accumulation and filling of products made crack self-healing, thereby improving the durability of the cracked mortar. © 2022, The Authors. All rights reserved.

关键词： Sewage

Cathode Potential Regulates the Microbiome Assembly and Function in Electrostimulated Bio- Dechlorination System

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SSRN 2022年

作者： Li, Zhi-Ling Cao, Di Shi, Ke Liang, Bin Zhu, Zhongli Liu, Wenzong Nan, Jun Sun, Kai Wang, Ai-Jie State Key Laboratory of Urban Water Resources and Environment School of Environment Harbin Institute of Technology Harbin150090 China Shenzhen518055 China Key Lab of Structures Dynamic Behavior and Control of China Ministry of Education School of Civil Engineering Harbin Institute of Technology Harbin150090 China

Mechanism of microbiome assembly and function driven by cathode potential in electro-stimulated microbial reductive dechlorination system remain poorly understood. Here, core microbiome structure, interaction, function and assembly regulating by cathode potential were investigated in a 2,4,6-trichlorophenol bio-dechlorination system. The highest dechlorination rate(24.30μM/d)was observed under-0.36Vwith phenol as a major end metabolite, while, lower (-0.56V) or higher (0.04Vor-0.16V)potentials resulted in 1.3~3.8 times decreased of dechlorination kinetic constant. The lower the cathode potential, the higher the generated CH4 , revealing cathode participated in hydrogenotrophic methanogenesis. Taxonomic and functional structure of core microbiome significantly shifted within groups of -0.36V and -0.56V, with dechlorinators ( Desulfitobacteriu , Dehalobacter ), fermenters ( norank_f_Propionibacteriaceae , Dysgonomonas )and cathode-utilizing methanogen ( Methanosarcina ) highly enriched, and the more positive interactions between functional genera were found. The lowest number of nodes and links and the highest positive correlations were observed among constructed sub-networks classified by function, revealing simplified and strengthened cooperation of functional genera driven by group of -0.36 V. Cathode potential plays one important driver controlling core microbiome assembly, and the low potentials drove the assembly of major dechlorinating, methanogenic and electro-active genera to be more deterministic, while, the major fermenting genera were mostly governed by stochastic processes. © 2022, The Authors. All rights reserved.

关键词： Dechlorination

dynamic Characteristics and Force Analysis of Box Girder Under Tsunami Action Based On Level-Set Method

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SSRN 2024年

作者： Niu, Shilei Liu, Zhongxiang Guo, Tong Guo, Anxin Liu, Aimin School of Transportation Southeast University Nanjing210096 China Key Laboratory of Concrete and Prestressed Concrete Structures School of Civil Engineering Southeast University Nanjing210096 China Ministry-of-Education Key Laboratory of Structural Dynamic Behavior and Control School of Civil Engineering Harbin Institute of Technology Harbin150090 China China Energy Engineering Group Jiangsu No.1 Electric Power Construction Co. Ltd. Nanjing210001 China

Tsunamis pose significant threats to the safety of sea-crossing bridges. Understanding the dynamics of wave forces and girder responses during tsunami events is crucial for ensuring their safe maintenance. In this research, a 2D numerical flume with solitary waves was utilized to simulate tsunamis. The level-set method was used for the treatment of fluid-solid interface and free surface. The interaction between the tsunami and the bridge girder was replicated through real-time data exchange between the fluid and a spring-mass-damper system. Subsequently, the hydrodynamic behaviors of the fluid surrounding the box girder and the structural responses of the girder under tsunami conditions were examined through parametric analysis. Findings suggest that tsunami with larger wave height interacts with box girder for longer duration. The maximum resistance and moment occur at the instant when the fluid acts on the top plate. Considering fluid-structure interaction and bearing constraints, increasing bearing stiffness results in substantial reductions (79.28%~85.32%) in girder displacement. Additionally, the maximum horizontal displacement of the unsubmerged box girder exceeds that of the submerged state by 2.04mm. Moreover, horizontal forces on the box girder decrease by 19.25%~45.30%, while maximum horizontal compression and tension on the wave-facing side bearing decrease by 10.7%~14.8% and 25.7%~29.9%, respectively. The maximum compression is approximately 2.68~3.34 times the maximum tension. © 2024, The Authors. All rights reserved.

关键词： Numerical methods