检索结果-内蒙古大学图书馆

12th International Conference on Bridge Maintenance, Safety and Management, IABMAS 2024

作者： Strasser, L. Lienhart, W. Institute of Engineering Geodesy and Measurement Systems Graz University of Technology Austria

ISBN: (纸本)9781032770406

In order to ensure a safe operation of bridges and other civil infrastructure, efficient methods for condition assessment are necessary. Distributed Fiber Optic Sensing (DFOS) offers highly accurate monitoring and provides significant advantages over point-wise sensors. In order to assess the condition of an Austrian highway bridge, static and dynamic load tests have been performed. Two spans have been equipped with fiber optic cables and point-wise sensors. Through the use of Optical Backscatter Reflectometry (OBR), the strain distribution of the bridge spans under static load was measured. Additionally, the use of Distributed Acoustic Sensing (DAS) enabled the measurement of vibrations along the bridge spans under dynamic load. In this paper we demonstrate that through the use of complementary DFOS techniques, a more comprehensive analysis of the bridge’s behavior can be achieved. The resulting measurements are verified not only by the bridge’s numerical model, but also by co-located pointwise reference sensors. © 2024 The Author(s).

关键词： Dynamic loads

来源：评论

学校读者我要写书评

暂无评论

Performance Comparison of Different Vibration Control Strategies 4th

Performance Comparison of Different Vibration Control Strate...

引用

4th International Conference on Coordinating engineering for Sustainability and Resilience and the Midterm Conference of the COST Action CircularB on Implementation of Circular Economy in the Built Environment, CESARE 2024

作者： Miah, Mohammad Shamim Lienhart, Werner Institute of Engineering Geodesy and Measurement Systems Graz University of Technology Graz8010 Austria

ISBN: (纸本)9783031577994

Structural engineers are always struggling with the unpredictable complexities of the extreme vibration due to natural or human induced loads. It is not possible to eliminate the vibration from structures entirely what so ever. Therefore, in order to keep the structures safe and healthy, the vibration needs to be mitigated and that can be done by adopting passive, active or semi-active type control systems. Those aforementioned technologies come with a price, hence, it is not so straightforward to decide which technology should be adopted. The passive vibration systems (e.g. tuned mass damper, base-isolator) can be found both in many old and new structures due to their feasibility and simplicity. On the other hand, many modern structures are adopting active and semi-active control systems (e.g. dampers) as an alternative to achieve better control on structure. Both the active and semi-active control systems are more expensive than passive control systems but they offer better control on structures. In order to understand the discussed issue, herein, a comparative study has been performed to evaluated their performances. A detail comparison among passive, active and semi-active control alternatives have been conducted. The outcome shows that the passive control systems can be suitable where deformations are and the other alternatives would be beneficial where large deformations are expected. © The Author(s) 2024.

关键词： Vibration control

来源：评论

学校读者我要写书评

暂无评论

Distributed Vibration Monitoring of Bridges with Fiber Optic Sensing systems

Distributed Vibration Monitoring of Bridges with Fiber Optic...

引用

Experimental Vibration Analysis for Civil engineering Structures - EVACES 2023 - Volume 2

作者： Lienhart, Werner Strasser, Lisa Dumitru, Vlad Institute of Engineering Geodesy and Measurement Systems Graz University of Technology Graz Austria

ISBN: (纸本)9783031391163

Distributed fiber optic sensing (DFOS) is a well-established technique for monitoring slow strain changes of structures. However, until recently such methods were not suitable for the dynamic monitoring of bridges due to their low measurement rate of 0.1 Hz or less. New advances like Distributed Acoustic Sensing (DAS) enable the measurement of dynamic strain changes with measurement rates up to several kHz and over long distances of tens of kilometers. Hence, DAS is a very promising method for vibration-based assessment of civil engineering structures such as bridges. This article focuses on a real-world application of DAS for the ambient vibration monitoring of a highway bridge. Two spans of a steel-concrete composite bridge were equipped with a continuous sensing cable. Strain rate changes were measured over several timespans with a DAS interrogation unit. Contrary to conventional point-wise sensors, the DAS measurements enable the determination of the frequency response seamlessly along the entire spans. In order to assess the accuracy of the novel measurement approach, additional acceleration sensors were attached to the steel structure. Furthermore, dynamic displacements were directly observed with a tracking total station. The comparative analysis highlights the potential of DAS for civil structural health monitoring (CSHM). © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Structural health monitoring

来源：评论

学校读者我要写书评

暂无评论

Static and Dynamic Bridge Monitoring with Distributed Fiber Optic Sensing 14

Static and Dynamic Bridge Monitoring with Distributed Fiber ...

引用

14th International Workshop on Structural Health Monitoring: Designing SHM for Sustainability, Maintainability, and Reliability, IWSHM 2023

作者： Strasser, Lisa Lienhart, Werner Winkler, Madeleine Institute of Engineering Geodesy and Measurement Systems Graz University of Technology Steyrergasse 30 Graz8010 Austria

ISBN: (纸本)9781605956930

Structural health monitoring (SHM) of bridges and other critical infrastructure is progressively gaining more importance, especially since many bridges in Central Europe and North America are coming to the end of their design life time. Efficient monitoring is therefore necessary to ensure safe operation. In order to measure not only fast changes due to traffic loads but also slow changes caused by temperature or degradation, several different sensor types are usually needed. Distributed Fiber Optic Sensing (DFOS) can provide both static and dynamic information. This article focuses on the monitoring of a steel-concrete composite highway bridge in Austria. Two of the seven spans were equipped with fiber optic sensing cables. By using different DFOS techniques such as Distributed Acoustic Sensing (DAS) and Brillouin Optical Frequency Domain Analysis (BOFDA), both dynamic and static monitoring can be realized seamlessly along the sensing cables. The combination of both fiber optic measurement techniques allows the determination of the vibration behavior of the bridge where not only the eigenfrequencies can be observed, but also slow changes caused by external influences such as temperature. We demonstrate that individual vehicles can not only be identified in DAS measurements, but also characterized in terms of mass and speed. To verify the static and dynamic DFOS results, point-wise sensors such as Robotic Total Stations (RTS) and accelerometers are used as reference. © 2023 by DEStech Publi cations, Inc. All rights reserved

关键词： Structural health monitoring

来源：评论

学校读者我要写书评

暂无评论

Visualization and interpretation of structural health monitoring data in a 3D environment using virtual reality 11

Visualization and interpretation of structural health monito...

引用

11th International Conference on Structural Health Monitoring of Intelligent Infrastructure, SHMII 2022

作者： Bauer, Peter Lienhart, Werner Institute of Engineering Geodesy and Measurement Systems Graz University of Technology Austria

Monitoring tasks demand the recording of data from various input sources to gather all crucial information. These datasets are often linked only through their spatial topology and differ not only in their resolution but also in their geometrical dimension. It can be challenging to combine them and prepare adequate representations of the datasets for a comprehensive structural interpretation. Therefore, basic concepts from the Building Information Modelling (BIM) can be adapted for an improved analysis of complex structural datasets. The potential of object-based and dynamic 3D environments for the processing of structural health information is discussed in this paper. Moreover, an experimental software approach is demonstrated for the combined integration of 1D strain and temperature data, 2D images and 3D deformation data at the examples of a smart family home and a tunnel excavation site. The usage of Virtual Reality (VR) gear in this software gives an outlook at an adequate working environment for future human experts in field of structural health monitoring. © 2022 International Conference on Structural Health Monitoring of Intelligent Infrastructure: Transferring Research into Practice, SHMII. All rights reserved.

关键词： Structural health monitoring

来源：评论

学校读者我要写书评

暂无评论

Measured displacement data analysis and modelling for structural health monitoring

引用

Procedia Structural Integrity 2024年 64卷 476-483页

作者： Mohammad Shamim Miah Werner Lienhart Institute of Engineering Geodesy and Measurement Systems Graz University of Technology 8010 Graz Austria

Non-physics-based modeling is gaining attention in the area of structural health monitoring due to underlying advantages e.g. finite-element or physics-based model might not exist at all. Therefore, in case of aforementioned scenario, it may be useful to have a model that is developed via the use of time-series data instead of knowing the exact underlying physics. Such model can be developed using parametric, non-parametric, and system identification approach, where, later, the state-space based model quantities can be derived. In this study, experimentally measured time-series data (e.g. displacement) have been utilized to develop a representative model. Initially, the data has been passed through a screening and selection process including data cleaning and filtering. Subsequently, the filtered data has been validated with the original data to make sure that overall dynamics remain same. Later, cleaned data have been employed to have an illustrative model via employing autoregressive type models. The influence of the model orders have been investigated and a comparison of different results have been presented. Further, the least-squares approach has been adopted to minimizes the prediction errors to optimize overall performance. However, it needs to be mentioned as herein out-only measured data has been used therefore no transfer function can be derived also stabilization plot is not possible without having a transfer function. Finally, the developed models output have been validated in both time and frequency domain. In short, it has been observed that the model output may vary significantly depending on the model orders and noise contamination of the original signal. The investigated approach is beneficial for monitoring while physics-based models either not available or not possible to derive.

关键词： Structural health monitoring Least-squares approach Autoregressive model Data-based model Time frequency domain

来源：评论

学校读者我要写书评

暂无评论

Effect of sensors locations and magnitudes of dynamic loads on dynamical properties in structural health monitoring

引用

Procedia Structural Integrity 2024年 54卷 3-10页

作者： Mohammad Shamim Miah Werner Lienhart Institute of Engineering Geodesy and Measurement Systems Graz University of Technology 8010 Graz Austria

The monitoring of civil structures and infrastructures are gaining momentum due to the recent technological developments of the various sensors. Typically, almost all structures are vulnerable to dynamic loads which even add more challenges due to the variation of the input excitations amplitudes. Among available alternatives, accelerometers are widely used due to its performance and feasibility in the area of monitoring. After the selection of the sensor, it is a challenge to select and place those sensors in appropriate location (e.g., node must be avoided) to get the meaningful information for the structural health monitoring (SHM). To understand the aforementioned issues, herein, sensors (e.g. accelerometers) are placed on a laboratory setup on a steel bridge of 2m long. And various dynamic type loads have been employed to evaluate their effects experimentally. As for example, the estimated first resonant frequency from all sensors (e.g., locations 01-04) data was found about 5.4Hz under an abrupt impulse type loading condition (for the duration of 36-46 secs in Figure 1). However, the magnitudes in frequency spectrum plot differs quite a lot -46.33, -8.71, -5.79, and -5,01dB, respectively for the sensor locations 01-04. Further, it is observed that the magnitudes of the accelerations vary significantly for different sensor locations (01-04) such as 0.0108, 0.8137, 1.1347, and 1.1472 m/s2. The measured data was recorded with a sampling frequency of 4.80kHz and all the analyses have been performed via MATLAB. The observed behavior shows the critical (e.g. resonant frequencies, damping) dynamical properties of the bridge can be changed significantly due to the magnitudes of the applied excitations. Further, in addition to the magnitudes or variation of the input excitations, the implemented sensors in different location of the bridge shows that the aforementioned critical parameters can also be altered.

关键词： sensors structural health monitoring dynamic excitations, bridge acceleration

来源：评论

学校读者我要写书评

暂无评论

Static and dynamic monitoring of bridges with contactless techniques 12th

Static and dynamic monitoring of bridges with contactless te...

引用

12th International Conference on Bridge Maintenance, Safety and Management, IABMAS 2024

作者： Moser, T. Lienhart, W. Schill, F. Institute of Engineering Geodesy and Measurement Systems Graz University of Technology Austria i3mainz - Institute for Spatial Information and Surveying Technology University of Applied Sciences Mainz Germany

ISBN: (纸本)9781032770406

Modern geodetic sensors are capable of capturing static and dynamic monitoring data of civil structures with up to several hundred Hertz. In order to assess the potential of such sensors, a comparative field study at a multi span highway bridge in Austria was performed. In the field tests different geodetic sensors such as robotic total stations (RTS) and terrestrial laser scanners (TLS) both in 3D and profile configuration were used to observe the structural behaviour during controlled static and dynamic load tests. Two trucks were placed at different positions on the steel-concrete composite bridge and the displacements of two bridge decks were observed. Additionally, both trucks were crossing the bridge at constant speeds (5 km/h and 30 km/h). In this study it is shown that remote sensing techniques are an appropriate tool for bridge monitoring and can ensure undisturbed operation of civil structures, as well as high accurate deformation measurements. © 2024 The Editor(s).

关键词： Trucks

来源：评论

学校读者我要写书评

暂无评论

Vibration-based Monitoring and Dynamic Properties Identification via Sensor Fusion Strategy

Vibration-based Monitoring and Dynamic Properties Identifica...

引用

Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace systems 2022

作者： Miah, Mohammad S. Lienhart, Werner Institute of Engineering Geodesy and Measurement Systems Graz University of Technology Graz8010 Austria

ISBN: (数字)9781510649682

ISBN: (纸本)9781510649675

Structural health monitoring (SHM) of important structures such as bridges, skyscrapers, and tunnels are gaining attention due to the feasibility, availability, and prodigious development of data acquisition systems (DAQ) as well as various type of sensors. However, in order to get the most out of the sensory information/technologies an appropriate monitoring and management strategy is inevitable. Thus, this study focuses into identification & monitoring strategy by deploying a multi-sensors approach on a laboratory scale prototype bridge. The enforced sensors include directly mounted sensors like: (i) accelerometers, (ii) distributed strain sensing (DSS) systems, (iii) remote sensing techniques based on camera video streams, and (iv) laser distance meters. To attain the goals of this study, initially, the measured data of different sensors are evaluated and the results are prepared to interpret the performance of the sensors. Later, the crucial dynamical results in time and frequency domains (e.g. eigenfrequencies) of the tested bridge have been assessed for all sensors type. In a nutshell, the response observed via those sensors provides useful information which are essential for monitoring and assessments. Even though, any of those sensors are capable of measuring dynamic responses but accuracy and reliability might be a concern. Hence, a multi-sensor strategy would be beneficial for a flawless monitoring strategy to deal with various uncertainties (i.e., noise, resolution, measurement error) of the sensors. More specifically, monitoring with a multi-sensor strategy will be advantageous when accuracy is concerned (e.g. data-based model, feedback-loop) along with the complexities induced by extreme vibration. © 2022 SPIE.

关键词： Structural health monitoring

来源：评论

学校读者我要写书评

暂无评论

Unscented Kalman filter to deal with exaggerated states and parameters uncertainties 30

Unscented Kalman filter to deal with exaggerated states and ...

引用

30th International Conference on Noise and Vibration engineering, ISMA 2022 and 9th International Conference on Uncertainty in Structural Dynamics, USD 2022

作者： Miah, M.S. Lienhart, W. Graz University of Technology Institute of Engineering Geodesy and Measurement Systems Steyrergasse 30 Graz8010 Austria

ISBN: (纸本)9789082893151

Uncertainties induced by inherent properties as well as due to external loading conditions to structures are well-known but an unavoidable issue that requires serious attention to keep them safe. In order to tackle the aforementioned problem an appropriate structural health monitoring strategy is crucial. It is not feasible to employ as many sensors as the number of degree of freedoms of a dynamical system. Hence, essential missing states need to be estimated by adopting linear or nonlinear observer. In order to estimate missing state only, a linear observer is sufficient though only with limited noise. Therefore, to overcome the aforementioned issues, a nonlinear type observer is essential not only to cope with excessive noise but also to handle nonlinear systems. Due to the underlying advantages of the UKF, this study has adopted it to estimate missing states and identify parameters e.g. stiffness simultaneously. The goal is achieved numerically by considering various amounts of state and process noise as well as parameters uncertainties. © 2022 Proceedings of ISMA 2022 - International Conference on Noise and Vibration engineering and USD 2022 - International Conference on Uncertainty in Structural Dynamics. All rights reserved.

关键词： Structural health monitoring

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：