Structural Monitoring System Research Articles

Localizing and quantifying structural damage by means of a beetle swarm optimization algorithm

An efficient meta-heuristic algorithm, named beetle swarm optimization (BSO), is proposed to localize and quantify structural damage using limited vibration measurement data. The beetle antennae search (BAS) algorithm that imitats a random walking mechanism in nature was recently developed to solve the optimization problem. However, the ratio of convergence of this algorithm significantly relys on the random direction and deviation for high-dimensional problems. To overcome this shortcoming, the BSO inspired by the swarm intelligence strategy is proposed. In the iterative search process of the BSO, each beetle swarm moves in a random direction like the BAS and the swarm of beetles is cognitive with the optimal one for the searching behavior. Consequently, the optimal one is updated step by step until a better beetle appears. To demonstrate the capability and robustness of the BSO, numerical and experimental studies using limited vibration measurement data of an offshore wind turbine structure are carried out for structural damage identification. An novel objective function is established by combining natural frequencies with mode shapes of the structure. The numerical results show that the BSO can accurately localize and quantify various types of damage even in a noise and temperature variations polluted environment. Moreover, it has higher accuracy and faster convergence speed than the BAS and the particle swarm optimization (PSO) algorithms. These promising performances could contribute to establishing a structural monitoring system for safety assurance of wind turbine structures.

Structural condition monitoring system of steam/water piping in thermal power plant and its application

In view of the steam/water piping outside the boiler of thermal power unit, considering its spatial structure characteristics of long distance, large drop and the working conditions under high temperature, high pressure and flexible operation. On the base of the static and dynamic analysis of the structure, the key nodes and parameters of monitoring were selected, the method of sensor installation and debugging was put forward, which was easy to maintain and reliable. A distributed monitoring data acquisition and digital processing analysis system was developed. The monitoring results showed that the monitoring system ran stably and reliably, and the test data of each node could accurately reflect the structural state of the piping. The monitoring system has a strong engineering application value.

Hierarchical approach for uncertainty quantification and reliability assessment of guided wave-based structural health monitoring

In this article, a hierarchical approach is proposed for the design and assessment of a guided wave-based structural health monitoring system for the detection and localisation of barely visible impact damage in composite airframe structures. The hierarchical approach provides a systemic and practical way to establish guided wave-based structural health monitoring systems for different structures in the presence of uncertainties and to quantify system performance. The proposed approach is carried out in four steps: (1) determine optimal sensor placement for the target structure and its plausible impact scenarios, (2) set detection threshold for global damage index based on the noise level present in the required environmental and operations conditions, (3) detect damage in critical locations and quantify detection performance by calculating the probability of detection, probability of false alarm and detection accuracy and (4) locate the detected damage while also quantifying the accuracy of location estimation and the probability of correctly indicating if the damage is in an area critical to the integrity of the structure. The proposed approach is demonstrated in aircraft carbon fibre-reinforced polymer structures from coupon level (simple flat panels) to sub-component level (large flat panel with multiple carbon fibre-reinforced polymer stringers and aluminium frames) for the detection and localisation of barely visible impact damage.

Design and Validation of Android Smartphone Based Wireless Structural Vibration Monitoring System.

Vibration monitoring is one of crucial functions of structural health monitoring (SHM) systems. Traditional structural vibration monitoring usually relies on specialized sensors, data transmission and acquisition equipment, which are expensive and may not be easily available in urgently needed situations like post-disaster structural evaluation. Therefore, developing an affordable and efficient structural vibration monitoring technique becomes an important topic in SHM research. In this paper, the authors developed an android system APP that can easily convert multiple android smartphones into a wireless structural vibration monitoring system. To make the designed system reliable and easy to use, the server/client architecture is adopted. One smartphone is designated as the serve of the system to remotely control all other smartphones, which function as sensors to measure structural vibration. An efficient method is proposed herein to establish the smartphone-based structural vibration monitoring network, allowing the server smartphone to quickly and easily connect multiple sensor smartphones to form the wireless network for structural vibration monitoring. Additionally, a synchronization method is also proposed to synchronize different smartphones for simultaneously measuring structural vibration. To verify the time synchronization accuracy of the developed system, an experiment is designed and conducted. Moreover, a new analysis method of the time synchronization accuracy is also proposed, which verifies that the designed smartphone-based monitoring can achieve the millisecond-level time synchronization accuracy. Finally, a shaking table experiment is conducted on a three-story bench-scale structural model, the results of which demonstrate that the designed smartphone-based wireless structural vibration monitoring system can quite accurately identify the modal parameters of the tested structure.

Research on Wind Resistance and Monitoring Technology for Pole-line Structure in Transmission Lines

The research on wind resistance monitoring technology of typical cement pole-line structure in 10kv transmission line is carried out in view of the fact that the transmission lines in the coastal areas of South China are often threatened by typhoons. Firstly, a wind-resistant monitoring system for pole-line structures is established. Secondly, the method to determine the early warning value in the monitoring system is proposed and the whole finite element model of the pole-line is established. Then, the wind speed is transformed into wind load to determine the early warning value of wind speed according to the wind-pole fluid-solid coupling model. Finally, the correctness of the wind-resistant monitoring technology of the pole-line structure is verified by the results monitored by practical engineering. The research shows that the wind load on the surface of the conductor is non-uniform, which can be accurately calculated through the wind-pole fluid-solid coupling model; The structural response obtained by the whole finite element model of the pole-line structure can accurately reflect the actual stress state, which can be used to determine the early warning value of wind speed; The proposed wind-resistant monitoring system in transmission lines has been verified by practical projects and can be popularized.

High-velocity ice impact damage quantification in composite laminates using a frequency domain-based correlation approach

This paper investigates the feasibility of using a novel domain-based correlation approach derived from the complex frequency domain assurance criterion (CFDAC) for the detection and quantification of impact damage in composite laminates. The CFDAC is essentially a complex-valued two-dimensional indicator of the covariance between two sets of frequency response functions for each pair of spectral lines corresponding to vibration-response of pristine and damage states. The study focuses on damage induced by high-velocity ice impacts on carbon fiber laminated plates. The experimental results demonstrate that the proposed methodology correctly identifies the level of induced damage via a user-independent scalar damage indicator. Therefore, this approach has potential use as a damage indicator, which could be adapted as a structural assessment non-destructive method. This research aims to contribute to the further development of functional, autonomous, and reliable structural health monitoring systems for composite structures based on spectral-domain indices.

Safety monitoring system of steel truss structures in fire

The fire-induced collapse of steel structures is very likely to cause secondary casualties in fire rescue. In order to predict the structural response, as well as give early warning of the collapse location of steel truss structures in fire to the rescue team, this paper develops a safety monitoring system for steel truss structures. Firstly, the theoretical basis of the system, including the member failure index and the collapse index is derived. Secondly, a numerical example is analyzed in SAP2000 to illustrate the calculation process of the collapse index, and the results indicate that the limit value of the collapse index can be chosen as 0.45. Subsequently, the development of the system, including the theoretical framework, the design of the system, and the user interface, is described. Finally, the system is used to monitor a fire test on a steel truss roof structure. The comparison of the output and experimental results indicated that the system is able to evaluate the real-time status of the members and the global structure. Besides, the structural response predicted by the system can be given to the user 180 s ahead of time, which provides precious information for the fire brigades to determine a safer route during the rescue process.

Realtime Localization and Estimation of Loads on Aircraft Wings from Depth Images.

This paper deals with the development of a realtime structural health monitoring system for airframe structures to localize and estimate the magnitude of the loads causing deflections to the critical components, such as wings. To this end, a framework that is based on artificial neural networks is developed where features that are extracted from a depth camera are utilized. The localization of the load is treated as a multinomial logistic classification problem and the load magnitude estimation as a logistic regression problem. The neural networks trained for classification and regression are preceded with an autoencoder, through which maximum informative data at a much smaller scale are extracted from the depth features. The effectiveness of the proposed method is validated by an experimental study performed on a composite unmanned aerial vehicle (UAV) wing subject to concentrated and distributed loads, and the results obtained by the proposed method are superior when compared with a method based on Castigliano’s theorem.

Study of optical tag profile of the tag recognition measurement system in cultural heritage

Abstract This study exposes the process to identify the optimum optical tag profile to be used for monitoring the minimum relative displacement of two areas of the artwork. The purpose is to realize an efficient, precise, and accurate structural monitoring system with minimal invasiveness. In particular, it is designed to determine the enlargement of a crack on a fresco inside a closed environment, such as inside a church. Theoretical studies and measurements in a controlled environment are performed to identify the best mathematical distribution to be used as tags. The two small adhesive tags are the main components of the system, they are attached on the surface of the artwork and the acquisition of their images is performed through a high-resolution camera. An advanced least-squares fitting of quadratic curves and surfaces algorithms for the objective function are used to detect the relative distance between these optical tags. The appropriate parameters for monitoring potential cracks on cultural assets are determined with a fitting algorithm of an objective function. In this study, different bi-dimensional objective functions are considered to identify the best configuration.

Optimization on the intellectual monitoring system for structures based on acoustic emission and data mining

Abstract Structures show their health information through various forms during their service. Acoustic emission (AE) sensors can capture the relevant information, but fail to realize their value fully. AE, data mining (DM) and cloud computing have promoted the development of centralized management of structures health management (SHM) but accompanied by the slow response, high requirement for computing capacity. This paper puts forward an innovative concept combining AE, DM on fog computing and centralized management to improve these problems. Firstly, raw data are collected by the AE sensors system and transformed into fog node for DM, including removing useless data, consolidating, organizing, and visualizing the result. Then the concise results will be integrated into a data center for centralized management and visualization. This idea is verified by a case study. It includes both a systematic experiment and a real-world application. The test conducts two groups of beams according to actual bridges and gives two parameters analysis of the experiment data to find the characteristics between signals and performance. Then the results are applied into two real bridges for practical application and detect a critical point. It not only explains how this new concept works but also has practical significance for engineering managers.

Damage detection using electromechanical impedance spectra – development and validation of a non‐destructive structure monitoring system

Steel ConstructionVolume 13, Issue 2 p. 91-91 Editor's Recommendations Damage detection using electromechanical impedance spectra – development and validation of a non-destructive structure monitoring system First published: 15 May 2020 https://doi.org/10.1002/stco.202070204AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume13, Issue2May 2020Pages 91-91 RelatedInformation

Corrosion study of pipeline material for seabed sediment in tropical climate

Corrosive environments such as marine sediments can cause corrosion to steel pipelines at any time when certain conditions are met. Seabed sediment could cause severe corrosion damage due to its corrosiveness to the pipelines buried under it. Many consequences could take place in case if there is incident in oil/gas pipelines. Successfully identifying elements of corrosion in marine sediment would enhance the future of steel structure protection and monitoring systems. This article focuses on the behaviour of corrosion rate of steel located near shore environment and the aim is to determine the effect of sediment on corrosion of steel. To investigate that, simulated near shore sediment conditions have been used where the steel coupons buried in sediments which have different characteristics. Weight loss technique has been implemented to determine the weight loss rate of the steel specimens. Based on the results of this study, metal weight loss increases as the duration of exposure to seabed sediment environment become longer. The sea sediment simulated condition has given significant levels of corrosion. Conclusively, the corrosion rate of steel in seabed sediment located in tropical region is complicated and further studies are suggested.

Structural health evaluation of the prestressed concrete using advanced acoustic emission (AE) parameters

Acoustic emission (AE) is a promising technology for structural health monitoring to reduce costs and improve performance but hard to interpret. This paper puts forward an advanced deep neural network (DNN) method to dig information between AE parameters and performance of the structures since raw data obtained by the AE structural monitoring system is nearly useless without reinterpretation. Firstly, this study carried out a series of AE monitoring to catch crack signals of the prestressed concrete samples of cycle loads under three-point bending tests. The AE parameters analyzed include Amean, RA, LE, LQ, Amax, EA, Ve, and AK. The combination of them gives a comprehensive structural performance evaluation by the DNN model. The results show a good correlation between AE parameters with the crack activities of different loads. Amean, RA, LE are the critical parameters in detecting whether the structure meets the design strength requirement. The combination of all these parameters gives an overall assessment of the structures. Finally, the method applies to the monitoring of two real-world bridges and gets comprehensive evaluations for all the monitoring points. This paper not only addresses a systematic experiment and a comprehensive parameter analysis method to realize data interpretation, but also practical applications in real-world bridges.

Monitoring of a Historical Masonry Structure in Case of Induced Seismicity

ABSTRACT In case of induced seismicity, expectations from a structural monitoring system are different than in the case of natural seismicity. In this paper, monitoring results of a historical building in Groningen (Netherlands) in case of induced seismicity has been presented. Results of the monitoring, particularities of the monitoring in case of induced earthquakes, as well as the usefulness and need of various monitoring systems for similar cases are discussed. Weak soil properties dominate the structural response in the region; thus, the ground water monitoring as well as the interaction of soil movements with the structural response has also been scrutinized. The proposed study could be effectively used to monitor historical structures subjected to induced seismicity and provide useful information to asset owners to classify the structural health condition of structures in their care. It was shown that the in-plane cracks at the building would normally not be expected in this structure during small induced earthquakes happening in Groningen. One explanation provided here is that the soil parameters, such as shrinking of water-sensitive soil layers, in combination with small earthquakes, may cause settlements. The soil effects may superimpose with the earthquake effects eventually causing small cracks and damage.

Development of a Structural Monitoring System for Cable Bridges by Using Seismic Accelerometers

In this study, a structural health monitoring system for cable-stayed bridges is developed. In the system, condition assessment of the structure is performed based on measured records from seismic accelerometers. Response indices are defined to monitor structural safety and serviceability and derived from the measured acceleration data. The derivation process of the indices is structured to follow the transformation from the raw data to the final outcome. The process includes, noise filtering, baseline correction, numerical integration, and calculation of relative differences. The system is packed as a condition assessment program, which consists of four major process of the structural health evaluation: (i) format conversion of the raw data, (ii) noise filtering, (iii) generation of response indices, and (iv) condition evaluation. An example set of limit states is presented to evaluate the structural condition of the test-bed cable-stayed bridge.

A Displacement Frequency Response Function‐Based Approach for Locating Damage to Building Structures

Frequency response function (FRF) data can provide considerably more information on damage in the desired frequency range as compared to modal data extracted from a very limited range around resonances. Among structural health monitoring techniques, FRF‐based methods have the potential to locate structural damage. Conventional structural damage detection technology collects structural response data using contact systems, such as displacement or acceleration transducers. However, installing these contact systems can be costly in terms of labor, cost, and time. Several noncontact measurement technologies, such as optical, laser, radar, and GPS, have been developed to overcome these obstacles. Given the rapid advances in optical imaging hardware technology, the use of digital photography in structural monitoring systems has attracted considerable attention. This study develops a displacement FRF‐based approach to locate damage to building structures. The proposed damage location index, CurveFRFDI, improves the sensitivity of SubFRFDI, which is a substructure FRF‐based damage location index proposed by Lin et al. (2012). Moreover, the feasibility of applying the proposed approach to locate damage to building structures using displacement measured by a digital camera combined with digital image correlation techniques is also investigated in this study. A numerical example and an experimental example are presented to demonstrate the feasibility of using the proposed approach to locate damage to building structures for single and multiple nonadjacent damage locations.

Design of a new wireless data acquisition system for civil structural monitoring

Traditional civil structure wired monitoring systems suffer complicated wiring, high cost, poor flexibility, and available wireless sensors network (WSN)-based wireless monitoring systems are inconvenient to access the internet. In this paper, based on the 6LoWPAN means: IPv6 low-power wireless personal area network WSN, a new wireless data acquisition system is proposed for structural monitoring applications, which consists of data acquisition nodes, a border node and a remote monitoring centre. The hardware design of the wireless data acquisition system is based on the CC2538 wireless transceiver, and inertial sensors and temperature and humidity sensors are integrated. Based on the Contiki-3.0 embedded operating system, the embedded application software of 6LoWPAN data acquisition nodes and border router nodes are designed. The remote monitoring centre of structural monitoring system is developed using the graphical user interface development environment (GUIDE) tool of the MATLAB software. Experimental testing results show that the system is stable and reliable and can realise interconnection between 6LoWPAN network and traditional IPv4 network. Moreover, the network performance is satisfactory. Therefore, the proposed wireless structural monitoring system has a good practical engineering application value.

Design of a new wireless data acquisition system for civil structural monitoring

Traditional civil structure wired monitoring systems suffer complicated wiring, high cost, poor flexibility, and available wireless sensors network (WSN)-based wireless monitoring systems are inconvenient to access the internet. In this paper, based on the 6LoWPAN means: IPv6 low-power wireless personal area network WSN, a new wireless data acquisition system is proposed for structural monitoring applications, which consists of data acquisition nodes, a border node and a remote monitoring centre. The hardware design of the wireless data acquisition system is based on the CC2538 wireless transceiver, and inertial sensors and temperature and humidity sensors are integrated. Based on the Contiki-3.0 embedded operating system, the embedded application software of 6LoWPAN data acquisition nodes and border router nodes are designed. The remote monitoring centre of structural monitoring system is developed using the graphical user interface development environment (GUIDE) tool of the MATLAB software. Experimental testing results show that the system is stable and reliable and can realise interconnection between 6LoWPAN network and traditional IPv4 network. Moreover, the network performance is satisfactory. Therefore, the proposed wireless structural monitoring system has a good practical engineering application value.

Design of information management system for structural monitoring based on network fragmentation

Aiming at the shortcomings of current information management system, such as low security, poor economy and long response time, a design method of structure monitoring information management system based on network fragments is proposed. Firstly, the overall architecture of the network debris structure monitoring information management system is designed and the requirements of the monitoring information management system are analysed. Then, based on the analysis of the main characteristics of the network debris monitoring information management system, the modules and subsystems of the system are designed separately, and the system data management scheme is given. In this way, the design of structured monitoring information management system based on network fragments is completed. The experimental results show that the information management system can manage the network information safely and economically. The response time is short, and the overall performance of the structured monitoring information management system is improved.

Design of information management system for structural monitoring based on network fragmentation

Aiming at the shortcomings of current information management system, such as low security, poor economy and long response time, a design method of structure monitoring information management system based on network fragments is proposed. Firstly, the overall architecture of the network debris structure monitoring information management system is designed and the requirements of the monitoring information management system are analysed. Then, based on the analysis of the main characteristics of the network debris monitoring information management system, the modules and subsystems of the system are designed separately, and the system data management scheme is given. In this way, the design of structured monitoring information management system based on network fragments is completed. The experimental results show that the information management system can manage the network information safely and economically. The response time is short, and the overall performance of the structured monitoring information management system is improved.