检索结果-内蒙古大学图书馆

Comparison of engineering failures and seismic responses of 500 kV transformer-bushing systems in the 2022 Luding earthquake

引用

Earthquake engineering and engineering Vibration 2024年第4期23卷 1029-1041页

作者： Zhu Wang Wu Ming’er Xie Qiang Department of Structural Engineering Tongji UniversityShanghai 200092China Key Laboratory of Performance Evolution and Control for Engineering Structures(Tongji University) Shanghai 200092China

Cemented and mechanically clamped types of end fittings(fitting-C and fitting-M)are commonly used in transformer *** the Luding Ms 6.8 earthquake that occurred in China on September 5,2022,all transformer bushings with the two types of end fittings in a 500 kV substation were ***-earthquake field investigations were conducted,and the failures of the two types of bushings were *** elementary simulation models of the transformer-bushing systems were developed to simulate the engineering failures,and further compute their seismic responses for *** results indicate that the hitch lugs of the connection flange are structurally harmful to seismic ***-M can decrease the bending stiffness of the bushing due to the flexible sealing rubber *** it provides a more flexible connection that dissipates energy,the peak accelerations and relative displacements at the top of the bushing are significantly lower than those of the bushing with *** with fitting-C,fitting-M transfers the high-stress areas from the connection flange to the root of the porcelain,so the latter becomes the most vulnerable ***-M increases the failure risk of the low-strength porcelain,indicating the unsuitability of applying it in high-intensity fortification regions.

关键词： transformer bushing end fitting Luding earthquake,engineering failure seismic responses

来源：评论

学校读者我要写书评

暂无评论

Stress-strain relationship for reactive powder concrete with recycled powder under uniaxial compression

引用

Frontiers of Structural and Civil engineering 2024年第7期18卷 1015-1027页

作者： Peng ZHU Yunming ZHU Wenjun QU Liyu XIE College of Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education Tongji UniversityShanghai 200092China

The recycled powder(RP)from construction wastes can be used to partially replace cement in the preparation of reactive powder *** this paper,reactive powder concrete mixtures with RP partially replacing cement,and natural sand instead of quartz,are *** curing is used,instead of steam curing that is normally requested by standard for reactive powder *** influences of RP replacement ratio(0%,10%,20%,30%),silica fume proportion(10%,15%,20%),and steel fiber proportion(0%,1%,2%)are *** effects of RP,silica fume,and steel fiber proportion on compressive strength,elastic modulus,and relative absorption energy are analyzed,and theoretical models for compressive strength,elastic modulus,and relative absorption energy are established.A constitutive model for the uniaxial compressive stress-strain relationship of reactive powder concrete with RP is *** the increase of RP replacement ratio from 0% to 30%,the compressive strength decreases by 42% and elastic modulus decreases by 24%.

关键词： recycled powder reactive powder concrete elastic modulus relative absorbed energy stress-strain relationship

来源：评论

学校读者我要写书评

暂无评论

Multi-objective optimization of mechanical ventilation with the aid of purifiers in two scenarios:Regular operation and mitigating the spread of respiratory infectious diseases

引用

Building Simulation 2023年第5期16卷 795-811页

作者： Yiqun Li Yujie Fan Chengqiang Zhi Wei Ye Xu Zhang School of Mechanical Engineering Tongji UniversityShanghai 201804China Department of Building Science Tsinghua UniversityBeijing 100084China Key Laboratory of Engineering Structure Performance Evolution and Control Ministry of EducationTongji UniversityShanghai 200092China

COVID-19 and its impact on society have raised concerns about scaling up mechanical ventilation(MV)systems and the energy *** paper attempted to combine MV and portable air cleaners(PACs)to achieve acceptable indoor air quality(IAQ)and energy reduction in two scenarios:regular operation and mitigating the spread of respiratory infectious diseases(RIDs).We proposed a multi-objective optimization method that combined the NSGA-II and TOPSIS techniques to determine the total equivalent ventilation rate of the MV-PAC system in both *** concentrations of PM_(2.5) and CO_(2) were primary indicators for *** modified Wells-Riley equation was adopted to predict RID *** open office with an MV-PAC system was used to demonstrate the method’s ***,a field study was conducted to validate the method and evaluate occupants’perceptions of the MV-PAC *** showed that optimal solutions of the combined system can be obtained based on various IAQ requirements,seasons,outdoor conditions,*** regular operation,PACs were generally prioritized to maintain IAQ while reducing energy consumption even when outdoor PM_(2.5) concentration was *** can remain constant or be reduced at low *** RID scenarios,it is possible to mitigate transmissions when the quanta were<48 h^(−1).No significant difference was found in the subjective perception of the MV and ***,the effects of infiltration on the optimal solution can be ***,our results suggested that an MV-PAC system can replace the MV system for offices for daily use and RID mitigation.

关键词： mechanical ventilation portable air cleaners infiltration multi-objective open office

来源：评论

学校读者我要写书评

暂无评论

Identification of global main cable line shape parameters of suspension bridges based on local 3D point cloud

引用

Low-Carbon Materials and Green Construction 2025年第1期3卷 1-12页

作者： Li, Yurui Dan, Danhui Pan, Ruiyang College of Civil Engineering Tongji University 1239 Siping Road Shanghai200092 China Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education Shanghai China

Main cable line shape measurement and parameter identification are a critical task in the construction monitoring and service maintenance of suspension bridges. 3D LiDAR scanning can simultaneously obtain the coordinates of multiple points on the target, offering high accuracy and efficiency. As a result, it is expected to be used in applications requiring rapid, large-scale measurements, such as main cable line shape measurement for suspension bridges. However, due to the large span and tall main towers of suspension bridges, the LiDAR field of view often encounters obstructions, making it difficult to obtain high-quality point clouds for the entire bridge. The collected point clouds are typically unevenly distributed and of poor quality. Therefore, LiDAR is used to monitor the local cable line shape. This paper proposes an innovative non-uniform sampling method that adjusts the sampling density based on the main cable’s rate of change. Additionally, the Random Sample Consensus (RANSAC) algorithm, the ordinary least squares, and center-of-mass calibration are applied to identify and optimize the geometric parameters of the cross-section point cloud of the main cable. Given the strong design prior information available during suspension bridge construction, Bayesian theory is applied to predict and adjust the global line shape of the main cable. The study shows that using LiDAR for cable point cloud measurement enables rapid acquisition of high-precision point cloud data, significantly enhancing data collection efficiency. The method proposed in this paper offers advantages such as highly automated, low risk, low cost, and sustainability, making it suitable for green monitoring throughout the entire main cable construction process. © The Author(s) 2025.

关键词： Channel estimation

来源：评论

学校读者我要写书评

暂无评论

Measuring particle emissions from using electric toothbrushes

Measuring particle emissions from using electric toothbrushe...

引用

Healthy Buildings 2023: Asia and Pacific Rim

作者： Tang, Wenhao Li, Yiqun Hong, Yusong Ye, We School of Mechanical Engineering Tongji University China Key Laboratory of Engineering Structure Performance Evolution and Control Ministry of Education Tongji University China

ISBN: (纸本)9781713890850

The oral cavity, in particular, has emerged as a major source of particles that cause respiratory infectious diseases. In recent years, electric toothbrushes are gaining popularity as a cleaning product in people's daily life. However, the emission rates of the particles and the risk of spreading respiratory infectious diseases by using an electric toothbrush are still unclear. In this paper, we conducted experiments to measure particle emissions from such actions using a cavity mock-up and volunteers. First, a questionnaire and volunteer experiment were used to determine the preferences of a university population for toothbrushing. Second, a mock-up was constructed in a laboratory and a standardized procedure was designed to measure the emission rates and size distribution of the particles caused by toothbrushing. The results revealed the emission rate during brushing is affected by multiple factors, incluing toothbrush and toothpaste. © 2023 Healthy Buildings 2023: Asia and Pacific Rim. All rights reserved.

关键词： Mockups

来源：评论

学校读者我要写书评

暂无评论

Investigation of the longitudinal temperature accumulation and mitigation methods of an ultra-long underwater road tunnel

Investigation of the longitudinal temperature accumulation a...

引用

Healthy Buildings 2023: Asia and Pacific Rim

作者： Guo, Weichen Gao, Jun Zeng, Lingjie Ye, Wei School of Mechanical Engineering Tongji University Shanghai China Key Laboratory of Engineering Structure Performance Evolution and Control Ministry of Education Tongji University Shanghai China

ISBN: (纸本)9781713890850

Because heat dissipation of the traffic can accumulate along the tunnels, the temperature near the exit of an ultra-long underwater tunnel can be elevated significantly than that of the entrance. In this paper, methods to cost-effectively mitigate temperature accumulation for the Haitai Long River Passage (HLRP) were investigated as follows. First, the temperature profiles of the HLRP were obtained using CFD simulations of a 1:1 model. Second, field tests were carried out in the Shanghai Yangtze River Tunnel, similar to HLRP, in the winter and summer of 2022 to validate the CFD method. Third, the effects of jet-fan speeds and traffic volumes on temperature accumulations were discussed. Results showed that: 1) in normal conditions, the jet fans can mitigate temperature accumulation;2) logarithmic functions can be used to predict the temperature profiles in the tunnel;and 3) In traffic-jam conditions, local refrigeration can be implemented as a supplement to the jet fans to reduce temperature accumulation. © 2023 Healthy Buildings 2023: Asia and Pacific Rim. All rights reserved.

关键词： Temperature control

来源：评论

学校读者我要写书评

暂无评论

Differential pressure reset strategy based on reinforcement learning for chilled water systems

引用

Building Simulation 2022年第2期15卷 233-248页

作者： Xinfang Zhang Zhenhai Li Zhengwei Li Shunian Qiu Hai Wang School of Mechanical Engineering Tongji UniversityShanghaiChina Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education Tongji UniversityShanghaiChina

Air conditioning water systems account for a large proportion of building energy *** a pressure-controlled water system,one of the key measures to save energy is to adjust the differential pressure setpoints during ***,such adjustments are based either on certain rules,which rely on operator experience,or on complicated models that are not easy to *** this paper,a data-driven control method based on reinforcement learning is *** main idea is to construct an agent model that adapts to the researched *** of directly being told how to react,the agent must rely on its own experiences to *** with traditional control strategies,reinforcement learning control(RLC)exhibits more accurate and steady performances while maintaining indoor air temperature within a limited range.A case study shows that the RLC strategy is able to save substantial amounts of energy.

关键词： water system differential pressure reset reinforcement learning control energy saving

来源：评论

学校读者我要写书评

暂无评论

Confinement properties of circular concrete columns wrapped with prefabricated textile-reinforced fine concrete shells

引用

Frontiers of Structural and Civil engineering 2023年第10期17卷 1554-1570页

作者： Qin ZHANG Qiao-Chu YANG Xiang-Lin GU Yong JIANG Hai-Yang ZHU College of Civil and Transportation Engineering Hohai UniversityNanjing 210024China Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education Tongji UniversityShanghai 200092China School of Civil Engineering Suzhou University of Science and TechnologySuzhou 215009China

This paper proposes an innovative column composed of a core column(including both reinforced concrete(RC)and plain concrete(PC)columns)and a prefabricated textile-reinforced fine concrete(TRC)*** study the confinement properties of TRC shells on this novel type of concrete column,20 circular specimens,including 12 PC columns and 8 RC columns,were prepared for axial compressive *** key parameters,including the column size,reinforcing ratio of the carbon textile,concrete strength,and stirrup spacing,were *** results indicated that the compressive properties of the columns were improved by increasing the reinforcing ratio of the textile *** the case of TRC-confined PC columns,the maximum improvement in the peak load was 56.3%,and for TRC-confined RC columns,the maximum improvement was 60.2%.Based on the test results,an analytical model that can be used to calculate the stress–strain curves of prefabricated TRC shell-confined concrete columns has been *** calculated curves predicted by the proposed model agreed well with the test results.

关键词： textile-reinforced fine concrete prefabricated shell confined concrete column confinement properties stress–strain relationship

来源：评论

学校读者我要写书评

暂无评论

Calculation Model for Progressive Collapse Resistance of RC Beam-Column Assemblies Under Arbitrary Restraint Stiffness 6th

Calculation Model for Progressive Collapse Resistance of RC ...

引用

6th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil structures, SMAR 2022

作者： Yang, X.J. Lin, F. Gu, X.L. Department of Structural Engineering Tongji University Shanghai200092 China Key Laboratory of Performance Evolution and Control for Engineering Structures Tongji University Shanghai200092 China

ISBN: (纸本)9789819933617

Research on the whole-process mechanical behaviour of structural resistance to progressive collapse is the key of proposing an effective practical engineering design method. However, most of the existing theoretical studies on the progressive collapse of reinforced concrete (RC) frame only focused on a double-span beam-column assembly in the case of fixed end restraint. For the case of non-fixed end restraint, research on the progressive collapse resistance of the assembly was extremely limited. Based on the alternative load path (ALP) method, a RC beam-column assembly under arbitrary restraint stiffness was chosen as the object to propose an explicit calculation model of a double-span beam under concentrated load in this paper. On the basis of analysing the mechanism of progressive collapse, the calculation formulas for the bearing capacity-displacement of the assembly in the beam action (BA) mechanism stage, compressive arching action (CAA) mechanism stage and catenary action (CA) mechanism stage were derived in detail. In this calculation model, the influence of constraint conditions and beam-span ratio on the progressive collapse behaviour of the assembly could be emphatically considered. Finally, calculations were performed for progressive collapse tests for differences in restraint stiffness and the calculations were compared with the test results. Results demonstrated that the proposed calculation model could accurately predict the progressive collapse resistance of RC beam-column assemblies under arbitrary restraint stiffness. © Tongji University Press 2024.

关键词： Stiffness

来源：评论

学校读者我要写书评

暂无评论

Investigation of Seismic Behavior of Infilled RC Frames by Using DEM 6th

Investigation of Seismic Behavior of Infilled RC Frames by U...

引用

6th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil structures, SMAR 2022

作者： Zhou, Tian Yu, Qian-Qian Gu, Xiang-Lin Department of Structural Engineering Tongji University Shanghai200092 China Key Laboratory of Performance Evolution and Control for Engineering Structures Tongji University Shanghai200092 China

ISBN: (纸本)9789819933617

In this paper, the discrete element modeling method was employed to evaluate the seismic performance of masonry-infilled reinforced concrete (RC) frames. Three-dimensional discrete element models were developed and validated by using experimental data extracted from literature in terms of the lateral bearing capacity and hysteresis curve. Good agreement implied that the discrete element modeling could be used to predict the seismic performance of RC frames infilled with masonry walls with reasonable accuracy. © Tongji University Press 2024.

关键词： Walls (structural partitions)

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：