Mobile Agent Computing Paradigm for Building a Flexible Structural Health Monitoring Sensor Network

Abstract: Wireless structural health monitoring research has drawn great attention in recent years from various research groups. While sensor network approach is a feasible solution for structural health monitoring, the design of wireless sensor networks presents a number of challenges, such as adaptability and the limited communication bandwidth. To address these challenges, we explore the mobile agent approach to enhance the flexibility and reduce raw data transmission in wireless structural health monitoring sensor networks. An integrated wireless sensor network consisting of a mobile agent‐based network middleware and distributed high computational power sensor nodes is developed. These embedded computer‐based high computational power sensor nodes include Linux operating system, integrate with open source numerical libraries, and connect to multimodality sensors to support both active and passive sensing. The mobile agent middleware is built on a mobile agent system called Mobile‐C. The mobile agent middleware allows a sensor network moving computational programs to the data source. With mobile agent middleware, a sensor network is able to adopt newly developed diagnosis algorithms and make adjustment in response to operational or task changes. The presented mobile agent approach has been validated for structural damage diagnosis using a scaled steel bridge.     

基于无线传感器网络的绿色施工监测系统的研究

根据绿色施工涉及面广、制约性强、信息量大的特点,设计开发绿色施工智能监测系统,利用无线传输技术对施工过程中的数据进行采集,并通过数据中心进行分析、传递和共享。旨在对绿色施工实行计量信息化管理,为绿色施工项目决策提供可靠的依据,促进绿色施工管理流程的组织科学化,提高管理效率、增加绿色施工管理透明度、降低管理费用并强化成本控制;使绿色施工过程处在科学管理、合理监控下,充分整合各种资源优势,使绿色施工水平达到一个较高的管理水平。     

Scalable Structural Modal Identification Using Dynamic Sensor Network Data with STRIDEX

This article uses the formulation of the structural identification using expectation maximization (STRIDE) algorithm for compatibility with the truncated physical model (TPM) to enable scalable, output‐only modal identification using dynamic sensor network (DSN) data. The DSN data class is an adaptable and efficient technique for storing measurements from a very large number of sensing nodes, which is the case in mobile sensor networks and BIGDATA problems. In this article, the STRIDEX output‐only identification algorithm is proposed for the stochastic TPM to estimate structural modal properties (frequencies, damping ratios, and mode shapes) directly from DSN data. The spatial information produced by this novel algorithm, called STRIDEX (“X” for extended), is scalable, as demonstrated in a strategy to construct high‐resolution mode shapes from a single DSN data set using a series of independent identification runs. The ability to extract detailed structural system information from DSN data in a computationally scalable framework is a step toward mobile infrastructure informatics in a large urban setting. The performance of the STRIDEX algorithm is demonstrated, using the simulated response of a 5,000 DOF structure, and experimentally, using measurements from two mobile sensor cars, which scanned about 8,000 points on a beam specimen in the laboratory. In the experimental results, a mobile sensor is shown to provide over 120 times more mode shape points than a fixed sensor.     

Sensor Attitude Correction of Wireless Sensor Network for Acceleration‐Based Monitoring of Civil Structures

Wireless sensors are now becoming practical alternatives to traditional wired sensors in monitoring civil structures. Though many have been reported on acceleration‐based monitoring of civil structures using wireless sensor networks, sensor attitude that may be different from instrumentation plan has been a seemingly overlooked issue behind performance validation of the network. In this article, a technique to correct the sensor attitude is proposed for the wireless sensor network that measures 3D acceleration of civil structures. Six simple formulas to assess the well‐known 3D Euler angles (i.e., roll, pitch, and yaw) are derived using the gravity extracted from measured 3D acceleration and nonchanging direction of sensors on a stationary structure. The proposed technique is validated at a large‐scale wireless sensor network with 22 sensors in the respective attitudes on a truss bridge. First, attitudes assessed by the proposed method are compared with instrumentation plan. Then, mode shapes obtained before and after the correction are compared with those from finite element model. Comparison shows that quality of the mode shapes improves significantly by small amount of attitude correction less than 7°.     

Structural Model Updating and Health Monitoring with Incomplete Modal Data Using Gibbs Sampler

Abstract:   A new Bayesian model updating approach is presented for linear structural models. It is based on the Gibbs sampler, a stochastic simulation method that decomposes the uncertain model parameters into three groups, so that the direct sampling from any one group is possible when conditional on the other groups and the incomplete modal data. This means that even if the number of uncertain parameters is large, the effective dimension for the Gibbs sampler is always three and so high-dimensional parameter spaces that are fatal to most sampling techniques are handled by the method, making it more practical for health monitoring of real structures. The approach also inherits the advantages of Bayesian techniques: it not only updates the optimal estimate of the structural parameters but also updates the associated uncertainties. The approach is illustrated by applying it to two examples of structural health monitoring problems, in which the goal is to detect and quantify any damage using incomplete modal data obtained from small-amplitude vibrations measured before and after a severe loading event, such as an earthquake or explosion.     

环境激励振动模态分析在桥梁结构检测与健康监测中的应用

文中对试验模态分析(EMA),特别是基于环境激励的振动模态分析(AMA)的进展,及其在桥梁结构检测和健康监测的应用进行了综合评述.主要内容包括结构动力学特性在桥梁结构检测和健康监测中的作用,传统试验模态分析和环境激励模态分析的进展,以及环境激励模态分析在桥梁结构检测与健康监测应用实例.     

结构健康监测中传感器布点优化的研究进展

传感器布点优化(OSP)关系到结构监测系统(SHM)所采集信息的准确性及可靠性,是结构模型修改、损伤识别、状态评估的基础,是SHM中一个至关重要及热点研究问题。从优化目标(即传感器布点准则)及优化算法的角度对目前SHM中OSP方法进行综述,最后提出了对此领域中需要进一步研究的几个问题。     

A Structural Damage Neural Network Monitoring System

Abstract: Traditional methods for structural monitoring and damage assessment have been implemented largely through visual inspection and on-site tests. A system for automating this process should be able to record the various signatures of the structure to be monitored and issue a warning signal if there is a damage-related change in those signatures. In this paper, a general system for structural damage monitoring is proposed based on observations of other researchers and the results obtained from a case study of a physical and analytical model of a five-story steel frame. The proposed diagnostic system utilizes neural networks for identifying the damage associated with changes in structural signatures. The system is independent of the type of signatures used for monitoring. Two sets of neural networks were developed. The first set was trained with the results of a series of shaking-table experiments, while the second set was trained with the output produced from a finite-element model of the same test structure. The results show that the proposed system provides a suitable framework for automatic structural monitoring.     

基于无线传感网的结构监测评估系统在城市桥梁中应用

以石家庄槐安大桥为依托项目,基于无线传感网的结构安全监测评估系统以城市大型斜拉桥结构为平台,通过在桥梁结构的关键部位布设无线智能传感器监测节点,对桥梁的环境荷载、运营荷载、桥梁特征和桥梁响应等参数进行实时监测,评估桥梁运营状态.提出传感器前端智能算法和桥梁监测节点多目标约束优化方法,建立桥梁结构损伤成因智能识别方法,实...     

易损性分析在结构抗震及健康监测中的应用

为了有效地对日见增多的大型复杂结构进行日常管理和减少各种灾害的损失,从结构易损性的概念、基本原理入手,分析总结了易损性分析在结构抗震、桥梁抗震设计中的计算方法及其应用进展,并对各种方法的优劣进行了评述;对易损性分析在结构健康监测系统开发及传感器优化布设中应用的可行性进行了详细论述,并对其近期发展和应用情况进行了介绍;最后对易损性分析的发展前景进行了展望.     

无线传感器网络在地质工程领域的应用

无线传感器网络作为一种新兴的信息获取和处理技术,在地质工程领域具有广泛的应用前景。文章结合无线传感器网络的实时性、动态性、远程无线传输等特点,对地质工程中边坡失稳监测预报,地下采空区安全监测预警,地下水监测,河口、海岸线地质调查,地震预警以及震后地质调查等方面的应用进行了研究探讨,并且对无线传感器网络在以上几类工程中的应用进行了可行性分析。     

通用土木工程结构健康监测系统平台

目前土木工程结构健康监测系统都是针对特定结构物进行单独设计,考虑到监测系统的总体结构相同及存在大量通用功能模块,提出并建立了通用结构健康监测系统框架。在此框架内,用户可以方便地设计针对特定结构物的监测方案,包括监测内容及测点方案、仪器选型、结构评估方法等,从而方便快速地建立结构监测系统,不仅避免大量重复的软件开发工作,降低结构监测系统的成本,更重要的是为结构健康监测系统设计提供了一种通用的解决方案。     

基于Zigbee的无线传感器网络定位技术

文章简单地对无线定位的发展作了介绍,基于无线定位技术的发展以及目前使用比较广泛的定位算法,首先对定位系统的定位原理进行研究,然后利用接收信号强度指示RSSI(Received Signal Strength Indicator)定位技术对需定位的移动节点进行定位研究,最后完成了对定位系统的软件与硬件的设计。     

大型结构健康监测的无线传感系统

无线传感系统是将传感单元采集的数据经由无线方式发送至计算中心并按照监测系统的特点对数据进行处理的系统。简要介绍了无线传感系统的主体架构，近年来的研究成果，主要的技术问题和该系统在大型结构健康监测等领域中的应用前景，并且展示了一套自主研发的无线传感系统及其主要工作参数，如系统工作频段、工作模式等。     

Analysis of the strain transfer in a new FBG sensor for Structural Health Monitoring

Structural Health Monitoring (SHM) is a topic of great interest in structural engineering due to the ageing of the built infrastructures and the growing use of innovative structural systems and construction materials. Although several sensing technologies have been developed for use in SHM systems, fiber optic sensors, especially Fiber Bragg grating sensors (FBGs), are now attracting much attention due to their advantages over other types of sensors.This paper presents a new FBG strain sensor with an unsymmetrical packaging configuration designed to be fixed to the surface of the monitored structure. A 3D Finite Element numerical analysis of the sensor, packaging and adhesive used to fix the system to the host structure was conducted to study the influence of (1) the thickness and mechanical properties of the adhesive, and (2) the configuration of the packaging on the accuracy of the sensor. The results obtained from the numerical models show that the strains measured by the proposed system and the actual strains in the host structure differ by less than 2.5% due to the fact that the packaging contains only one layer of composite material in an unsymmetrical configuration. The proposed design can thus be said to be an improvement compared to the typical configurations of optical fiber surface strain sensors.     

无线传感器网络的特点与发展趋势

阐述了无线传感器网络的特点,论述了其发展趋势。     

无线传感器网络的特点与发展趋势

阐述了无线传感器网络的特点,论述了其发展趋势。     

桥梁健康无线监测系统关键技术研究

将现代光纤传感器与无线通信技术相结合应用于桥梁的健康监测,使各个环节得到优化：在绝对位移监测单元采用精确的差分式全球定位系统GPS;在形变温度监测单元采用光纤光栅传感器;在控制单元采用GPRS发送装置;在数据处理单元采用Visual Basic建立相应的数据库等。优化后可以达到对桥梁进行无线实时遥控监测的目的。     

基于BIM的结构健康监测研究

随着建筑结构的大型化、复杂化,利用结构健康监测(Structural health monitoring)技术评判结构的安全状态是非常重要的。本文基于BIM技术,结合数据库管理和传感通信技术构建了SHM系统框架,利用参数化设计工具Dynamo,由BIM模型自动访问SHM数据库,通过阈值设定,将损伤构件映射到BIM模型上,实现基于SHM数据进行结构状态评估的可视化预警能力。