检索结果-南通市图书馆

基于自感知纤维增强复合材料锚杆的隧道围岩松动圈识别

在线全文

学校读者我要写书评

暂无评论

西南交通大学学报 2024年第1期59卷 11-19页

作者：李锦辉张俊齐魏强贾大鹏郭东白石欧进萍哈尔滨工业大学(深圳)深圳市土木工程智能结构系统重点实验室广东深圳518055 中国国家铁路集团有限公司北京100844 智性纤维复合加固南通有限公司江苏南通226010

隧道围岩变形和松动圈厚度是隧道结构设计的重要考虑因素和安全运营的重要参考依据,现有的松动圈识别方法和隧道围岩变形测量手段多停留在检测层面,缺乏长期实时监测方法.为此,研发内嵌光纤的自感知纤维增强复合材料(FRP)锚杆,提出基于... 详细信息

隧道围岩变形和松动圈厚度是隧道结构设计的重要考虑因素和安全运营的重要参考依据,现有的松动圈识别方法和隧道围岩变形测量手段多停留在检测层面,缺乏长期实时监测方法.为此,研发内嵌光纤的自感知纤维增强复合材料(FRP)锚杆,提出基于内嵌光纤自感知FRP锚杆的隧道围岩智能监测系统,可以实现对围岩变形立体化、全天候的实时监测;结合监测数据与理论分析,提出隧道围岩松动圈的识别方法,并将该智能监测方法应用于广汕高铁陈塘隧道.研究结果表明:自感知FRP锚杆能够精准探知现场施工对围岩变形的影响规律,型钢钢架对隧道围岩的支护作用较为突出;监测数据可以实时反映自感知锚杆的受力规律,从而准确识别隧道不同位置围岩的松动圈厚度;基于自感知FRP锚杆的隧道围岩智能监测系统将在隧道运营过程中持续、实时监测隧道围岩的变形,为隧道全生命周期的结构安全提供高技术保障.

关键词：智能监测松动圈围岩变形光纤光栅自感知FRP锚杆

Design approaches for active,semi-active and passive control systems based on analysis of characteristics of active control force

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2009年第4期8卷 493-506页

作者： ou jinping Li Hui School of Civil ＆ Hydraulic Engineering Dalian University of Technology Dalian 116024 China School of Civil Engineering Harbin Institute of Technology Harbin 150090 China

In this paper, the characteristics of forces in active control systems connected to adjacent levels of a building are analyzed. The following characteristics are observed：（1） active control can provide significantly superior supplemental damping to a building, but causes a small frequency shift; （2） the linear quadratic regulator （LQR）-based control force is composed of an elastic restoring force component and a damping force component, where the damping force is almost identical to the total control force, however, the elastic restoring force is very small; and （3） the active control forces prevent mction most of the time during the entire control process. These three characteristics imply that active control systems connected to adjacent levels of a building behave like passive damping devices with adjustable parameters, namely damping characteristics in an active control, which is the mechanism used by semi-active control devices to reach similar performance as active control systems. Two indices are defined to quantify the damping characteristics of control forces in active control systems. These two indices can also be used to quantify the capacity of semi-active control to achieve the perfonrlance of active control. Based on the above observations, two principles are founded for optimization of parameters of semi-active control devices and passive dampers. The first is that the maximum output force of a semi-active or passive device to be designed is identical to an active device, called ＂design principle＂. The other is the response equivalent principle, which states that the response of a building with semi-active or passive devices is the same as with active devices when the same maximum output force is applied. The design procedure for semi-active control devices and passive dampers is described in detail. Finally, numerical simulations of two benchmark problems is conducted to demonstrate the damping characteristics of active control and investigate the c

关键词： active control: semi-active control smart control damping design approach

A macro-level global seismic damage model considering higher modes

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2014年第3期13卷 425-436页

作者： He Zheng ou Xiaoying ou jinping Department of Civil Engineering Dalian University of Technology School of Civil Engineering Harbin Institute of Technology

For modal pushover analysis procedures, the model proposed by Ghobarah et al. （called the G model hereafter, 1999） has been extended to account for the contributions of transient higher modes to global seismic damage of structures excited by strong ground motions. The proposed model has physically and perfectly bridged the G model and the final softening model proposed by DiPasquale and Cakmak （1988）. Modal damage indexes corresponding to all considered vibration modes are combined by the CQC rule or the SRSS rule. Incremental dynamic analysis （IDA） is performed on three example RC frames to validate the proposed model, and a comprehensive comparison is carried out. The demonstration indicates that the proposed model is easy to implement and reflects the influence of the transition in transient vibration periods and modes on structural damage evolution. Some limitations associated with the proposed model are also addressed. Further experimental validations are needed to improve the model in the future.

关键词： seismic damage modal pushover analysis incremental dynamic analysis

Realization of the global yield mechanism of RC frame structures by redesigning the columns using column tree method

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2015年第10期58卷 1627-1637页

作者： BAI JiuLin ou jinping School of Civil Engineering Harbin Institute of Technology Key Lab of Structures Dynamic Behavior and Control (Harbin Institute of Technology) Ministry of Education

Global failure mechanism, i.e., the strong-column weak-beam mechanism, can provide higher total energy dissipation capacity with less ductility demand on components than other failure modes, and results in a more uniform story drift distribution and higher resistance to earthquake loads at the system level. However, the current code-based elastic design method cannot guarantee the global failure mechanism of frame structures under severe earthquakes. In this paper, a simple, but practical design procedure is proposed to ensure the global failure mechanism of reinforced concrete(RC) frame structures by redesigning the columns using the column tree method(CTM). CTM considers the yield limit state of all beams and column bases. The code-based design is firstly carried out to determine the section information of all beams and base columns. Then, the internal force demands applied on the column tree can be derived. Lastly, the column moments, shear forces and axial forces are determined according to the free-body diagram of CTM to finish the column redesign. Two RC frame structures with 6 and 12 stories are illustrated to verify the design procedure. The analytical results demonstrate the proposed approach can realize the global failure mechanism.

关键词： global failure mechanism column tree method (CTM) reinforced concrete frame structures failure mode plastic hinges

Pressure distributions on prism-shaped buildings in experimentally simulated downburst

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2014年第10期57卷 2070-2081页

作者： LI HongHai ou jinping School of Civil Engineering Harbin Institute of Technology

Wind loading is one of the most significant factors in civil engineering that influences the structural design *** this paper,a group of manufacturing equipments for downburst simulation based on impinging jet model was developed for investigating the wind loads on structures:including the centrifugal air bellows to generate airflow,a movable platform to realize multiple locations of the building and a freely rotatable turntable to implement alterable building *** of transducers were used to measure the wind action on all surfaces of the *** pressure coefficients calculated from the observed data were utilized to evaluate the downburst wind *** distributions on three prism-shaped building models with different placements and angles were investigated to obtain the maximum wind action and mean pressure *** results showed that the maximum pressure coefficient would reach 1.0 on the top surface if the downburst just broke out over the *** that the building was in the developing field of the downburst,the top and the front surfaces would be under high wind pressure and only the back surface would endure wind *** the downdraft happens away from the prismatic building,all surfaces,except the front surface,would subject to suction with different *** was also found that the pressure coefficient on the right surface would get its negative peak at first and then go straight up to 0.6 as the angle changed from 0°to 45°and the wind pressure on the front surface would decrease slightly through the whole *** assertive results provide elemental data for structural wind-resistant design in civil engineering for the downburst-prone areas.

关键词： wind loading downburst pressure coefficient building structure impinging jet model

Seismic failure mode improvement of RC frame structure based on multiple lateral load patterns of pushover analyses

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2011年第11期54卷 2825-2833页

作者： BAI JiuLin ou jinping School of Civil Engineering Harbin Institute of Technology Harbin 150090 China Faculty oflnfrastructure Engineering Dalian University of Technology Dalian 116024 China

The structural failure under severe ground motions is primarily caused by their unreasonable seismic failure mode (SFM). This paper provides a methodology aiming at the SFM improvement of reinforced concrete frame structure. An RC frame is modeled and three types of failure criterion are defined as the premise of SFM. Static pushover analysis is adopted to identify the SFM. The dominant failure modes and failure paths of the structure are obtained in three lateral load patterns (inverted trian- gular distribution, uniform distribution and adaptive distribution). Based on the pushover analysis, the sequential failure of components and the probability of the occurrence of plastic hinges are determined. By this, weak components of the structure are detected and herein are strengthened. The project cost of the proposed strengthening strategy increases by 2.4%. Capacity spectrum method is used to study the performance of the strengthening structure. Pushover analysis is conducted again to present the improvement of strength and ductility. Lateral drift and local response through IDA are also studied to indicate that the strengthening of some columns and beams can improve the SFM to enhance the seismic capacity of structure.

关键词： seismic failure modes (SFM) improvement failure path pushover incremental dynamic analysis (IDA)

BP-PSO-based intelligent case retrieval method for high-rise structural form selection

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2013年第4期56卷 940-944页

作者： ZHANG ShiHai ou jinping School of Civil Engineering Nanyang Institute of Technology Faculty of Infrastructure Engineering Dalian University of Technology

Modern architectures are developing in the direction of tall buildings and complex structures,and the theoretical analysis and the design experience have seriously lagged behind the construction of super high-rise *** form selection,especially the case based reasoning (CBR) based structural form selection,is a promising tool for the construction of high-rise *** view of the limit of cognitive ability of domain experts,a BP (back propagation)-PSO (particle swarm optimization)-based intelligence case retrieval method for high-rise structural form selection is *** CBR-based case retrieval method and the construction of the BP-PSO neutral network are *** then the BP-PSO-based case retrieval method is validated by some engineering *** results of training and prediction indicate that the proposed method has good ability to retrieve the cases of high-rise structures.

关键词： structural form selection case based reasoning high-rise structure BP-PSO neutral network

Substructure isolation and damage identification using free responses

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2014年第9期57卷 1698-1706页

作者： Hou JiLin JANKOWSKI Lukasz ou jinping School of Civil Engineering Dalian University of Technology Smart-Tech Centre Institute of Fundamental Technological Research Polish Academy of Sciences School of Civil Engineering Harbin Institute of Technology

Structural health monitoring （SHM） has become a hot and intensively researched field in civil engineering. Thereinto, damage identification play an important role in maintaining structural integrity and safety. Many effective methods have been proposed for damage identification. However, accurate global identification of large real-world structures is not easy due to their com- plex and often unknown boundary conditions, nonlinear components, insensitivity of glohal response to localized damages, etc. Furthermore, global identification often requires lots of sensors and involves large number of unknowns. This is costly, rarely feasible in practice, and usually yields severely ill-conditioned identification problems. Substructuring approach is a possible solution： substructuring methods can focus on local small substructures; they need only a few sensors placed on the substruc- ture and yield smaller and numerically much more feasible identification problems. This paper proposed an improved sub- structure method using local free response for substructure damage identification. The virtual supports are constructed by Sub- structure Isolation Method （SIM） using the linear combination of the substructural responses. The influence of the global errors is isolated by adding the virtual supports on the main degree of freedoms （DOFs） of the substructure. Through the correlation analysis, the substructural modes are selected and used for damage identification of the substructure. A plain model of cable stayed bridge is used for the verification of the proposed method.

关键词： structural health monitoring (SHM) damage identification substructure cable stayed bridge free response

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

在线全文

学校读者我要写书评

暂无评论

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 ***-time monitoring of steel strand stress distribution throughout the damage process is an impor-tant aspect of civil infrastructure health ***,this study proposes an optical-electrical co-sensing(OECS)smart steel strand with the DOFS and CCFPI embedded *** can simultaneously measure small strains in the initial damage phase with high accuracy and obtain information in the large deformation phase with relatively low *** experiments were carried out to test its sensing *** shows both DOFS and CCFPI have good linearity,repeatability and *** 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 *** 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 *** 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