Cointegration and why it works for SHM

Science.gov (United States)

Cross, Elizabeth J.; Worden, Keith

2012-08-01

One of the most fundamental problems in Structural Health Monitoring (SHM) is that of projecting out operational and environmental variations from measured feature data. The reason for this is that algorithms used for SHM to detect changes in structural condition should not raise alarms if the structure of interest changes because of benign operational or environmental variations. This is sometimes called the data normalisation problem. Many solutions to this problem have been proposed over the years, but a new approach that uses cointegration, a concept from the field of econometrics, appears to provide a very promising solution. The theory of cointegration is mathematically complex and its use is based on the holding of a number of assumptions on the time series to which it is applied. An interesting observation that has emerged from its applications to SHM data is that the approach works very well even though the aforementioned assumptions do not hold in general. The objective of the current paper is to discuss how the cointegration assumptions break down individually in the context of SHM and to explain why this does not invalidate the application of the algorithm.

Development of Structural Health Monitoring System for pipes in Nuclear Power Plants

International Nuclear Information System (INIS)

Eom, H. S.; Choi, Y. C.; Shin, S. H.; Youn, D. B.; Park, J. H.

2010-01-01

Structural health monitoring (SHM) has becoming an important issue in the maintenance of various structures such as large steel plates, vessels, and pipes in nuclear power plants. There are important factors to be considered in developing an SHM system. With consideration of these factors, we have developed a computerized multi-channel ultrasonic system that can handle array transducers and generate a high-power pulse for online SHM of the plates and pipes. The proposed system is compact but has all the necessary functions for SHM of important structure such as pipes and plates in a NPP

Fatigue of Ti6Al4V Structural Health Monitoring Systems Produced by Selective Laser Melting

Directory of Open Access Journals (Sweden)

Maria Strantza

2016-02-01

Full Text Available Selective laser melting (SLM is an additive manufacturing (AM process which is used for producing metallic components. Currently, the integrity of components produced by SLM is in need of improvement due to residual stresses and unknown fracture behavior. Titanium alloys produced by AM are capable candidates for applications in aerospace and industrial fields due to their fracture resistance, fatigue behavior and corrosion resistance. On the other hand, structural health monitoring (SHM system technologies are promising and requested from the industry. SHM systems can monitor the integrity of a structure and during the last decades the research has primarily been influenced by bionic engineering. In that aspect a new philosophy for SHM has been developed: the so-called effective structural health monitoring (eSHM system. The current system uses the design freedom provided by AM. The working principle of the system is based on crack detection by means of a network of capillaries that are integrated in a structure. The main objective of this research is to evaluate the functionality of Ti6Al4V produced by the SLM process in the novel SHM system and to confirm that the eSHM system can successfully detect cracks in SLM components. In this study four-point bending fatigue tests on Ti6Al4V SLM specimens with an integrated SHM system were conducted. Fractographic analysis was performed after the final failure, while finite element simulations were used in order to determine the stress distribution in the capillary region and on the component. It was proven that the SHM system does not influence the crack initiation behavior during fatigue. The results highlight the effectiveness of the eSHM on SLM components, which can potentially be used by industrial and aerospace applications.

Application of modern SHM methods in electric power industry

Energy Technology Data Exchange (ETDEWEB)

Gasior, Pawel; Kaleta, Jerzy [Wroclaw Univ. of Technolgy (Poland); Przygoda, Aleksander [RAFAKO S.A., Raciborz (Poland)

2012-07-01

In this paper an application of up-to-date Structural Health Monitoring systems based mainly on optical fibre sensors for various applications in power plants is presented. Real working solutions and ideas of the SHM systems were applied to fluid power boilers, installations of environmental protection (the so called desulphurisation systems) and main frames of construction (130m high). The measured values were compared with the design ones, as well as with the calculated values. It enabled evaluation of the inhomogeneous loads distribution and increased safety of the construction during its repair and operation. (orig.)

Monitoring osseointegration and developing intelligent systems (Conference Presentation)

Science.gov (United States)

Salvino, Liming W.

2017-05-01

Effective monitoring of structural and biological systems is an extremely important research area that enables technology development for future intelligent devices, platforms, and systems. This presentation provides an overview of research efforts funded by the Office of Naval Research (ONR) to establish structural health monitoring (SHM) methodologies in the human domain. Basic science efforts are needed to utilize SHM sensing, data analysis, modeling, and algorithms to obtain the relevant physiological and biological information for human-specific health and performance conditions. This overview of current research efforts is based on the Monitoring Osseointegrated Prosthesis (MOIP) program. MOIP develops implantable and intelligent prosthetics that are directly anchored to the bone of residual limbs. Through real-time monitoring, sensing, and responding to osseointegration of bones and implants as well as interface conditions and environment, our research program aims to obtain individualized actionable information for implant failure identification, load estimation, infection mitigation and treatment, as well as healing assessment. Looking ahead to achieve ultimate goals of SHM, we seek to expand our research areas to cover monitoring human, biological and engineered systems, as well as human-machine interfaces. Examples of such include 1) brainwave monitoring and neurological control, 2) detecting and evaluating brain injuries, 3) monitoring and maximizing human-technological object teaming, and 4) closed-loop setups in which actions can be triggered automatically based on sensors, actuators, and data signatures. Finally, some ongoing and future collaborations across different disciplines for the development of knowledge automation and intelligent systems will be discussed.

Active Wireless System for Structural Health Monitoring Applications.

Science.gov (United States)

Perera, Ricardo; Pérez, Alberto; García-Diéguez, Marta; Zapico-Valle, José Luis

2017-12-11

The use of wireless sensors in Structural Health Monitoring (SHM) has increased significantly in the last years. Piezoelectric-based lead zirconium titanate (PZT) sensors have been on the rise in SHM due to their superior sensing abilities. They are applicable in different technologies such as electromechanical impedance (EMI)-based SHM. This work develops a flexible wireless smart sensor (WSS) framework based on the EMI method using active sensors for full-scale and autonomous SHM. In contrast to passive sensors, the self-sensing properties of the PZTs allow interrogating with or exciting a structure when desired. The system integrates the necessary software and hardware within a service-oriented architecture approach able to provide in a modular way the services suitable to satisfy the key requirements of a WSS. The framework developed in this work has been validated on different experimental applications. Initially, the reliability of the EMI method when carried out with the proposed wireless sensor system is evaluated by comparison with the wireless counterpart. Afterwards, the performance of the system is evaluated in terms of software stability and reliability of functioning.

New strategies for SHM based on a multichannel wireless AE node

Science.gov (United States)

Godinez-Azcuaga, Valery; Ley, Obdulia

2014-03-01

This paper discusses the development of an Acoustic Emission (AE) wireless node and its application for SHM (Structural Health Monitoring). The instrument development was planned for applications monitoring steel and concrete bridges components. The final product, now commercially available, is a sensor node which includes multiple sensing elements, on board signal processing and analysis capabilities, signal conditioning electronics, power management circuits, wireless data transmission element and energy harvesting unit. The sensing elements are capable of functioning in both passive and active modes, while the multiple parametric inputs are available for connecting various sensor types to measure external characteristics affecting the performance of the structure under monitoring. The output of all these sensors are combined and analyzed at the node in order to minimize the data transmission rate, which consumes significant amount of power. Power management circuits are used to reduce the data collection intervals through selective data acquisition strategies and minimize the sensor node power consumption. This instrument, known as the 1284, is an excellent platform to deploy SHM in the original bridge applications, but initial prototypes has shown significant potential in monitoring composite wind turbine blades and composites mockups of Unmanned Autonomous Vehicles (UAV) components; currently we are working to extend the use of this system to fields such as coal flow, power transformer, and off-shore platform monitoring.

On the value of SHM in the context of service life integrity management

DEFF Research Database (Denmark)

Qin, Jianjun; Thöns, Sebastian; Faber, Michael Havbro

2015-01-01

This paper addresses the optimization of structural health monitoring(SHM) before its implementation on the basis of its Value of Information (VoI). The approach for the quantification of the value of SHM builds upon a service life cost assessment and generic structural performance model...... in conjunction with the observation, i.e. monitoring, of deterioration increments. The structural performance is described with a generic deterioration model to be calibrated to the relevant structural deterioration mechanism, such as e.g. fatigue and corrosion. The generic deterioration model allows...... for the incorporation of monitored damage increments and accounts for the precision of the data by considering the statistical uncertainties, i.e. the amount of monitoring data due to the monitoring period, and by considering the measurement uncertainty. The value of structural health monitoring is then quantified...

Automated wireless monitoring system for cable tension using smart sensors

Science.gov (United States)

Sim, Sung-Han; Li, Jian; Jo, Hongki; Park, Jongwoong; Cho, Soojin; Spencer, Billie F.; Yun, Chung-Bang

2013-04-01

Cables are critical load carrying members of cable-stayed bridges; monitoring tension forces of the cables provides valuable information for SHM of the cable-stayed bridges. Monitoring systems for the cable tension can be efficiently realized using wireless smart sensors in conjunction with vibration-based cable tension estimation approaches. This study develops an automated cable tension monitoring system using MEMSIC's Imote2 smart sensors. An embedded data processing strategy is implemented on the Imote2-based wireless sensor network to calculate cable tensions using a vibration-based method, significantly reducing the wireless data transmission and associated power consumption. The autonomous operation of the monitoring system is achieved by AutoMonitor, a high-level coordinator application provided by the Illinois SHM Project Services Toolsuite. The monitoring system also features power harvesting enabled by solar panels attached to each sensor node and AutoMonitor for charging control. The proposed wireless system has been deployed on the Jindo Bridge, a cable-stayed bridge located in South Korea. Tension forces are autonomously monitored for 12 cables in the east, land side of the bridge, proving the validity and potential of the presented tension monitoring system for real-world applications.

A variable-frequency structural health monitoring system based on omnidirectional shear horizontal wave piezoelectric transducers

Science.gov (United States)

Huan, Qiang; Miao, Hongchen; Li, Faxin

2018-02-01

Structural health monitoring (SHM) is of great importance for engineering structures as it may detect the early degradation and thus avoid life and financial loss. Guided wave based inspection is very useful in SHM due to its capability for long distance and wide range monitoring. The fundamental shear horizontal (SH0) wave based method should be most promising since SH0 is the unique non-dispersive wave mode in plate-like structures. In this work, a sparse array SHM system based on omnidirectional SH wave piezoelectric transducers (OSH-PT) was proposed and the multi data fusion method was used for defect inspection in a 2 mm thick aluminum plate. Firstly, the performances of three types OSH-PTs was comprehensively compared and the thickness-poled d15 mode OSH-PT used in this work was demonstrated obviously superior to the other two. Then, the signal processing method and imaging algorithm for this SHM system was presented. Finally, experiments were carried out to examine the performance of the proposed SHM system in defect localization and imaging. Results indicated that this SHM system can locate a through hole as small as 0.12λ (4 mm) in diameter (where λ is the wavelength corresponding to the central operation frequency) under frequencies from 90 to 150 kHz. It can also locate multiple defects accurately based on the baseline subtraction method. Obviously, this SHM system can detect larger areas with sparse sensors because of the adopted single mode, non-dispersive and low frequency SH0 wave which can propagate long distance with small attenuation. Considering its good performances, simple data processing and sparse array, this SH0 wave-based SHM system is expected to greatly promote the applications of guided wave inspection.

Active Wireless System for Structural Health Monitoring Applications

Directory of Open Access Journals (Sweden)

Ricardo Perera

2017-12-01

Full Text Available The use of wireless sensors in Structural Health Monitoring (SHM has increased significantly in the last years. Piezoelectric-based lead zirconium titanate (PZT sensors have been on the rise in SHM due to their superior sensing abilities. They are applicable in different technologies such as electromechanical impedance (EMI-based SHM. This work develops a flexible wireless smart sensor (WSS framework based on the EMI method using active sensors for full-scale and autonomous SHM. In contrast to passive sensors, the self-sensing properties of the PZTs allow interrogating with or exciting a structure when desired. The system integrates the necessary software and hardware within a service-oriented architecture approach able to provide in a modular way the services suitable to satisfy the key requirements of a WSS. The framework developed in this work has been validated on different experimental applications. Initially, the reliability of the EMI method when carried out with the proposed wireless sensor system is evaluated by comparison with the wireless counterpart. Afterwards, the performance of the system is evaluated in terms of software stability and reliability of functioning.

Use of Savitzky-Golay Filter for Performances Improvement of SHM Systems Based on Neural Networks and Distributed PZT Sensors.

Science.gov (United States)

de Oliveira, Mario A; Araujo, Nelcileno V S; da Silva, Rodolfo N; da Silva, Tony I; Epaarachchi, Jayantha

2018-01-08

A considerable amount of research has focused on monitoring structural damage using Structural Health Monitoring (SHM) technologies, which has had recent advances. However, it is important to note the challenges and unresolved problems that disqualify currently developed monitoring systems. One of the frontline SHM technologies, the Electromechanical Impedance (EMI) technique, has shown its potential to overcome remaining problems and challenges. Unfortunately, the recently developed neural network algorithms have not shown significant improvements in the accuracy of rate and the required processing time. In order to fill this gap in advanced neural networks used with EMI techniques, this paper proposes an enhanced and reliable strategy for improving the structural damage detection via: (1) Savitzky-Golay (SG) filter, using both first and second derivatives; (2) Probabilistic Neural Network (PNN); and, (3) Simplified Fuzzy ARTMAP Network (SFAN). Those three methods were employed to analyze the EMI data experimentally obtained from an aluminum plate containing three attached PZT (Lead Zirconate Titanate) patches. In this present study, the damage scenarios were simulated by attaching a small metallic nut at three different positions in the aluminum plate. We found that the proposed method achieves a hit rate of more than 83%, which is significantly higher than current state-of-the-art approaches. Furthermore, this approach results in an improvement of 93% when considering the best case scenario.

Use of Savitzky–Golay Filter for Performances Improvement of SHM Systems Based on Neural Networks and Distributed PZT Sensors

Science.gov (United States)

Araujo, Nelcileno V. S.; da Silva, Rodolfo N.; da Silva, Tony I.; Epaarachchi, Jayantha

2018-01-01

A considerable amount of research has focused on monitoring structural damage using Structural Health Monitoring (SHM) technologies, which has had recent advances. However, it is important to note the challenges and unresolved problems that disqualify currently developed monitoring systems. One of the frontline SHM technologies, the Electromechanical Impedance (EMI) technique, has shown its potential to overcome remaining problems and challenges. Unfortunately, the recently developed neural network algorithms have not shown significant improvements in the accuracy of rate and the required processing time. In order to fill this gap in advanced neural networks used with EMI techniques, this paper proposes an enhanced and reliable strategy for improving the structural damage detection via: (1) Savitzky–Golay (SG) filter, using both first and second derivatives; (2) Probabilistic Neural Network (PNN); and, (3) Simplified Fuzzy ARTMAP Network (SFAN). Those three methods were employed to analyze the EMI data experimentally obtained from an aluminum plate containing three attached PZT (Lead Zirconate Titanate) patches. In this present study, the damage scenarios were simulated by attaching a small metallic nut at three different positions in the aluminum plate. We found that the proposed method achieves a hit rate of more than 83%, which is significantly higher than current state-of-the-art approaches. Furthermore, this approach results in an improvement of 93% when considering the best case scenario. PMID:29316693

Use of Savitzky–Golay Filter for Performances Improvement of SHM Systems Based on Neural Networks and Distributed PZT Sensors

Directory of Open Access Journals (Sweden)

Mario A. de Oliveira

2018-01-01

Full Text Available A considerable amount of research has focused on monitoring structural damage using Structural Health Monitoring (SHM technologies, which has had recent advances. However, it is important to note the challenges and unresolved problems that disqualify currently developed monitoring systems. One of the frontline SHM technologies, the Electromechanical Impedance (EMI technique, has shown its potential to overcome remaining problems and challenges. Unfortunately, the recently developed neural network algorithms have not shown significant improvements in the accuracy of rate and the required processing time. In order to fill this gap in advanced neural networks used with EMI techniques, this paper proposes an enhanced and reliable strategy for improving the structural damage detection via: (1 Savitzky–Golay (SG filter, using both first and second derivatives; (2 Probabilistic Neural Network (PNN; and, (3 Simplified Fuzzy ARTMAP Network (SFAN. Those three methods were employed to analyze the EMI data experimentally obtained from an aluminum plate containing three attached PZT (Lead Zirconate Titanate patches. In this present study, the damage scenarios were simulated by attaching a small metallic nut at three different positions in the aluminum plate. We found that the proposed method achieves a hit rate of more than 83%, which is significantly higher than current state-of-the-art approaches. Furthermore, this approach results in an improvement of 93% when considering the best case scenario.

Integration of structural health monitoring solutions onto commercial aircraft via the Federal Aviation Administration structural health monitoring research program

Science.gov (United States)

Swindell, Paul; Doyle, Jon; Roach, Dennis

2017-02-01

The Federal Aviation Administration (FAA) started a research program in structural health monitoring (SHM) in 2011. The program's goal was to understand the technical gaps of implementing SHM on commercial aircraft and the potential effects on FAA regulations and guidance. The program evolved into a demonstration program consisting of a team from Sandia National Labs Airworthiness Assurance NDI Center (AANC), the Boeing Corporation, Delta Air Lines, Structural Monitoring Systems (SMS), Anodyne Electronics Manufacturing Corp (AEM) and the FAA. This paper will discuss the program from the selection of the inspection problem, the SHM system (Comparative Vacuum Monitoring-CVM) that was selected as the inspection solution and the testing completed to provide sufficient data to gain the first approved use of an SHM system for routine maintenance on commercial US aircraft.

Statistical analysis of modal parameters of a suspension bridge based on Bayesian spectral density approach and SHM data

Science.gov (United States)

Li, Zhijun; Feng, Maria Q.; Luo, Longxi; Feng, Dongming; Xu, Xiuli

2018-01-01

Uncertainty of modal parameters estimation appear in structural health monitoring (SHM) practice of civil engineering to quite some significant extent due to environmental influences and modeling errors. Reasonable methodologies are needed for processing the uncertainty. Bayesian inference can provide a promising and feasible identification solution for the purpose of SHM. However, there are relatively few researches on the application of Bayesian spectral method in the modal identification using SHM data sets. To extract modal parameters from large data sets collected by SHM system, the Bayesian spectral density algorithm was applied to address the uncertainty of mode extraction from output-only response of a long-span suspension bridge. The posterior most possible values of modal parameters and their uncertainties were estimated through Bayesian inference. A long-term variation and statistical analysis was performed using the sensor data sets collected from the SHM system of the suspension bridge over a one-year period. The t location-scale distribution was shown to be a better candidate function for frequencies of lower modes. On the other hand, the burr distribution provided the best fitting to the higher modes which are sensitive to the temperature. In addition, wind-induced variation of modal parameters was also investigated. It was observed that both the damping ratios and modal forces increased during the period of typhoon excitations. Meanwhile, the modal damping ratios exhibit significant correlation with the spectral intensities of the corresponding modal forces.

Benchmarking of Computational Models for NDE and SHM of Composites

Science.gov (United States)

Wheeler, Kevin; Leckey, Cara; Hafiychuk, Vasyl; Juarez, Peter; Timucin, Dogan; Schuet, Stefan; Hafiychuk, Halyna

2016-01-01

Ultrasonic wave phenomena constitute the leading physical mechanism for nondestructive evaluation (NDE) and structural health monitoring (SHM) of solid composite materials such as carbon-fiber-reinforced polymer (CFRP) laminates. Computational models of ultrasonic guided-wave excitation, propagation, scattering, and detection in quasi-isotropic laminates can be extremely valuable in designing practically realizable NDE and SHM hardware and software with desired accuracy, reliability, efficiency, and coverage. This paper presents comparisons of guided-wave simulations for CFRP composites implemented using three different simulation codes: two commercial finite-element analysis packages, COMSOL and ABAQUS, and a custom code implementing the Elastodynamic Finite Integration Technique (EFIT). Comparisons are also made to experimental laser Doppler vibrometry data and theoretical dispersion curves.

Damage Detection with Streamlined Structural Health Monitoring Data

OpenAIRE

Li, Jian; Deng, Jun; Xie, Weizhi

2015-01-01

The huge amounts of sensor data generated by large scale sensor networks in on-line structural health monitoring (SHM) systems often overwhelms the systems’ capacity for data transmission and analysis. This paper presents a new concept for an integrated SHM system in which a streamlined data flow is used as a unifying thread to integrate the individual components of on-line SHM systems. Such an integrated SHM system has a few desirable functionalities including embedded sensor data compressio...

Approaches to nonlinear cointegration with a view towards applications in SHM

Science.gov (United States)

Cross, E. J.; Worden, K.

2011-07-01

One of the major problems confronting the application of Structural Health Monitoring (SHM) to real structures is that of divorcing the effect of environmental changes from those imposed by damage. A recent development in this area is the import of the technique of cointegration from the field of econometrics. While cointegration is a mature technology within economics, its development has been largely concerned with linear time-series analysis and this places a severe constraint on its application - particularly in the new context of SHM where damage can often make a given structure nonlinear. The objective of the current paper is to introduce two possible approaches to nonlinear cointegration: the first is an optimisation-based method; the second is a variation of the established Johansen procedure based on the use of an augmented basis. Finally, the ideas of nonlinear cointegration will be explored through application to real SHM data from the benchmark project on the Z24 Highway Bridge.

Approaches to nonlinear cointegration with a view towards applications in SHM

International Nuclear Information System (INIS)

Cross, E J; Worden, K

2011-01-01

One of the major problems confronting the application of Structural Health Monitoring (SHM) to real structures is that of divorcing the effect of environmental changes from those imposed by damage. A recent development in this area is the import of the technique of cointegration from the field of econometrics. While cointegration is a mature technology within economics, its development has been largely concerned with linear time-series analysis and this places a severe constraint on its application - particularly in the new context of SHM where damage can often make a given structure nonlinear. The objective of the current paper is to introduce two possible approaches to nonlinear cointegration: the first is an optimisation-based method; the second is a variation of the established Johansen procedure based on the use of an augmented basis. Finally, the ideas of nonlinear cointegration will be explored through application to real SHM data from the benchmark project on the Z24 Highway Bridge.

Uncertainty and sensitivity analysis of electro-mechanical impedance based SHM system

International Nuclear Information System (INIS)

Rosiek, M; Martowicz, A; Uhl, T

2010-01-01

The paper deals with the application of uncertainty and sensitivity analysis performed for FE simulations for electro-mechanical impedance based SHM system. The measurement of electro-mechanical impedance allows to follow changes of mechanical properties of monitored construction. Therefore it can be effectively applied to conclude about presence of damage. Coupled FE simulations have been carried out for simultaneous consideration of both structural dynamics and piezoelectric properties of a simple beam with bonded transducer. Several indexes have been used to assess the damage growth. In the paper the results obtained with both deterministic and stochastic simulations are shown and discussed. First, the relationship between size of introduced damage and its indexes has been studied. Second, ranges of variation of selected model properties have been assumed to find relationships between them and damage indexes. The most influential parameters have been found. Finally, the overall propagation of considered uncertainty has been assessed and related histograms plotted to discuss effectiveness and robustness of tested damage indexes based on the measurement of electro-mechanical impedance.

Uncertainty Evaluation in the Design of Structural Health Monitoring Systems for Damage Detection†

Directory of Open Access Journals (Sweden)

Christine Schubert Kabban

2018-04-01

Full Text Available The validation of structural health monitoring (SHM systems for aircraft is complicated by the extent and number of factors that the SHM system must demonstrate for robust performance. Therefore, a time- and cost-efficient method for examining all of the sensitive factors must be conducted. In this paper, we demonstrate the utility of using the simulation modeling environment to determine the SHM sensitive factors that must be considered for subsequent experiments, in order to enable the SHM validation. We demonstrate this concept by examining the effect of SHM system configuration and flaw characteristics on the response of a signal from a known piezoelectric wafer active sensor (PWAS in an aluminum plate, using simulation models of a particular hot spot. We derive the signal responses mathematically and through the statistical design of experiments, we determine the significant factors that affect the damage indices that are computed from the signal, using only half the number of runs that are normally required. We determine that the transmitter angle is the largest source of variation for the damage indices that are considered, followed by signal frequency and transmitter distance to the hot spot. These results demonstrate that the use of efficient statistical design and simulation may enable a cost- and time-efficient sequential approach to quantifying sensitive SHM factors and system validation.

SHM reliability and implementation - A personal military aviation perspective

Science.gov (United States)

Lindgren, Eric A.

2016-02-01

Structural Health Monitoring has been proposed as a solution to address the needs of military aviation to reduce the time and cost to perform nondestructive inspections. While the potential to realize significant benefits exist, there are considerations that have to be addressed before such systems can be integrated into military platforms. Some considerations are pervasive to all aviation, such as how to assess the reliability and reproducible capability of these systems. However, there are other challenges unique to military aviation that must be overcome before these types of systems can be used. This presentation and paper are intended as a complement to the review of the outcome of the SAE G-11 SHM committee special workshop on SHM reliability in April of 2015. It will address challenges unique to military aviation that stem from different approaches to managing structural integrity (i.e. safety), frequency of use, design differences, various maintenance practices, and additional descriptions addressing differences in the execution of inspections. The objective of this presentation is to improve the awareness of the research and development community to the different and unique requirements found in military aviation, including the differences between countries, services, and aircraft type. This information should assist the research and development community in identifying and attacking key challenges. It is not intended to be comprehensive overview of all stakeholders' perspectives, but to serve as a launch point for additional discussion and exploration of opportunities to realize the potential of Structural Health Monitoring to assist in the management of military aviation assets. The views expressed in this publication are those of the author and do not reflect the official policy or position of the United States Air Force, Department of Defense, or the United States Government.

Frequency Selective Surface for Structural Health Monitoring

Science.gov (United States)

Norlyana Azemi, Saidatul; Mustaffa, Farzana Hazira Wan; Faizal Jamlos, Mohd; Abdullah Al-Hadi, Azremi; Soh, Ping Jack

2018-03-01

Structural health monitoring (SHM) technologies have attained attention to monitor civil structures. SHM sensor systems have been used in various civil structures such as bridges, buildings, tunnels and so on. However the previous sensor for SHM is wired and encounter with problem to cover large areas. Therefore, wireless sensor was introduced for SHM to reduce network connecting problem. Wireless sensors for Structural Health monitoring are new technology and have many advantages to overcome the drawback of conventional and wired sensor. This project proposed passive wireless SHM sensor using frequency selective surface (FSS) as an alternative to conventional sensors. The electromagnetic wave characteristic of FSS will change by geometrical changes of FSS due to mechanical strain or structural failure. The changes feature is used as a sensing function without any connecting wires. Two type of design which are circular ring and square loop along with the transmission and reflection characteristics of SHM using FSS were discussed in this project. A simulation process has shown that incident angle characteristics can be use as a data for SHM application.

Energy Harvesting for Aerospace Structural Health Monitoring Systems

International Nuclear Information System (INIS)

Pearson, M R; Eaton, M J; Pullin, R; Featherston, C A; Holford, K M

2012-01-01

Recent research into damage detection methodologies, embedded sensors, wireless data transmission and energy harvesting in aerospace environments has meant that autonomous structural health monitoring (SHM) systems are becoming a real possibility. The most promising system would utilise wireless sensor nodes that are able to make decisions on damage and communicate this wirelessly to a central base station. Although such a system shows great potential and both passive and active monitoring techniques exist for detecting damage in structures, powering such wireless sensors nodes poses a problem. Two such energy sources that could be harvested in abundance on an aircraft are vibration and thermal gradients. Piezoelectric transducers mounted to the surface of a structure can be utilised to generate power from a dynamic strain whilst thermoelectric generators (TEG) can be used to generate power from thermal gradients. This paper reports on the viability of these two energy sources for powering a wireless SHM system from vibrations ranging from 20 to 400Hz and thermal gradients up to 50°C. Investigations showed that using a single vibrational energy harvester raw power levels of up to 1mW could be generated. Further numerical modelling demonstrated that by optimising the position and orientation of the vibrational harvester greater levels of power could be achieved. However using commercial TEGs average power levels over a flight period between 5 to 30mW could be generated. Both of these energy harvesting techniques show a great potential in powering current wireless SHM systems where depending on the complexity the power requirements range from 1 to 180mW.

Opportunities and challenges for structural health monitoring of radioactive waste systems and structures

Energy Technology Data Exchange (ETDEWEB)

Giurgiutiu, Victor [University of South Carolina, Columbia, SC 29208 (United States); Mendez Torres, Adrian E. [Savannah River National Laboratory, Aiken, SC 29808 (United States)

2013-07-01

Radioactive waste systems and structures (RWSS) are safety-critical facilities in need of monitoring over prolonged periods of time. Structural health monitoring (SHM) is an emerging technology that aims at monitoring the state of a structure through the use of networks of permanently mounted sensors. SHM technologies have been developed primarily within the aerospace and civil engineering communities. This paper addresses the issue of transitioning the SHM concept to the monitoring of RWSS and evaluates the opportunities and challenges associated with this process. Guided wave SHM technologies utilizing structurally-mounted piezoelectric wafer active sensors (PWAS) have a wide range of applications based on both propagating-wave and standing-wave methodologies. Hence, opportunities exist for transitioning these SHM technologies into RWSS monitoring. However, there exist certain special operational conditions specific to RWSS such as: radiation field, caustic environments, marine environments, and chemical, mechanical and thermal stressors. In order to address the high discharge of used nuclear fuel (UNF) and the limited space in the storage pools the U.S. the Department of Energy (DOE) has adopted a 'Strategy for the Management and Disposal of Used Nuclear Fuel and High-Level Radioactive Waste' (January 2013). This strategy endorses the key principles that underpin the Blue Ribbon Commission's on America's Nuclear Future recommendations to develop a sustainable program for deploying an integrated system capable of transporting, storing, and disposing of UNF and high-level radioactive waste from civilian nuclear power generation, defense, national security, and other activities. This will require research to develop monitoring, diagnosis, and prognosis tools that can aid to establish a strong technical basis for extended storage and transportation of UNF. Monitoring of such structures is critical for assuring the safety and security of the

A feasibility study on embedded micro-electromechanical sensors and systems (MEMS) for monitoring highway structures.

Science.gov (United States)

2011-06-01

Micro-electromechanical systems (MEMS) provide vast improvements over existing sensing methods in the context of structural health monitoring (SHM) of highway infrastructure systems, including improved system reliability, improved longevity and enhan...

TLP Structural Health Monitoring Based on Vibration Signal of Energy Harvesting System

Directory of Open Access Journals (Sweden)

Vahid Jahangiri

Full Text Available Abstract Structural Health Monitoring (SHM of Tension Leg Platform (TLP is very crucial for preventing catastrophic and sudden collapse of the structures. One of the methods of monitoring these structures is implementing SHM sensors. Supplying energy for these sensors for a long period is a challenging problem. So, one of the new methods of supplying energy for SHM, is usage of mechanical energy. In this method, the piezoelectric material is employed to convert the mechanical energy which is resulted from vibration of structure, to electrical energy. The advantage of this method is based on not implementing the battery charging system. Therefore, in this paper, after modeling TLP structure, energy supplying of these sensors with piezoelectric converters is studied. Furthermore, fault diagnosis of these structures in the presence of different uncertainties is proposed by the features of voltage signal, produced from piezoelectric patches and fuzzy classification method. Results show that this method can diagnose faults of the structure with an acceptable success rate.

Guided waves based SHM systems for composites structural elements: statistical analyses finalized at probability of detection definition and assessment

Science.gov (United States)

Monaco, E.; Memmolo, V.; Ricci, F.; Boffa, N. D.; Maio, L.

2015-03-01

Maintenance approaches based on sensorised structures and Structural Health Monitoring systems could represent one of the most promising innovations in the fields of aerostructures since many years, mostly when composites materials (fibers reinforced resins) are considered. Layered materials still suffer today of drastic reductions of maximum allowable stress values during the design phase as well as of costly and recurrent inspections during the life cycle phase that don't permit of completely exploit their structural and economic potentialities in today aircrafts. Those penalizing measures are necessary mainly to consider the presence of undetected hidden flaws within the layered sequence (delaminations) or in bonded areas (partial disbonding); in order to relax design and maintenance constraints a system based on sensors permanently installed on the structure to detect and locate eventual flaws can be considered (SHM system) once its effectiveness and reliability will be statistically demonstrated via a rigorous Probability Of Detection function definition and evaluation. This paper presents an experimental approach with a statistical procedure for the evaluation of detection threshold of a guided waves based SHM system oriented to delaminations detection on a typical wing composite layered panel. The experimental tests are mostly oriented to characterize the statistical distribution of measurements and damage metrics as well as to characterize the system detection capability using this approach. Numerically it is not possible to substitute part of the experimental tests aimed at POD where the noise in the system response is crucial. Results of experiments are presented in the paper and analyzed.

Damage detection with streamlined structural health monitoring data.

Science.gov (United States)

Li, Jian; Deng, Jun; Xie, Weizhi

2015-04-15

The huge amounts of sensor data generated by large scale sensor networks in on-line structural health monitoring (SHM) systems often overwhelms the systems' capacity for data transmission and analysis. This paper presents a new concept for an integrated SHM system in which a streamlined data flow is used as a unifying thread to integrate the individual components of on-line SHM systems. Such an integrated SHM system has a few desirable functionalities including embedded sensor data compression, interactive sensor data retrieval, and structural knowledge discovery, which aim to enhance the reliability, efficiency, and robustness of on-line SHM systems. Adoption of this new concept will enable the design of an on-line SHM system with more uniform data generation and data handling capacity for its subsystems. To examine this concept in the context of vibration-based SHM systems, real sensor data from an on-line SHM system comprising a scaled steel bridge structure and an on-line data acquisition system with remote data access was used in this study. Vibration test results clearly demonstrated the prominent performance characteristics of the proposed integrated SHM system including rapid data access, interactive data retrieval and knowledge discovery of structural conditions on a global level.

Damage Detection with Streamlined Structural Health Monitoring Data

Directory of Open Access Journals (Sweden)

Jian Li

2015-04-01

Full Text Available The huge amounts of sensor data generated by large scale sensor networks in on-line structural health monitoring (SHM systems often overwhelms the systems’ capacity for data transmission and analysis. This paper presents a new concept for an integrated SHM system in which a streamlined data flow is used as a unifying thread to integrate the individual components of on-line SHM systems. Such an integrated SHM system has a few desirable functionalities including embedded sensor data compression, interactive sensor data retrieval, and structural knowledge discovery, which aim to enhance the reliability, efficiency, and robustness of on-line SHM systems. Adoption of this new concept will enable the design of an on-line SHM system with more uniform data generation and data handling capacity for its subsystems. To examine this concept in the context of vibration-based SHM systems, real sensor data from an on-line SHM system comprising a scaled steel bridge structure and an on-line data acquisition system with remote data access was used in this study. Vibration test results clearly demonstrated the prominent performance characteristics of the proposed integrated SHM system including rapid data access, interactive data retrieval and knowledge discovery of structural conditions on a global level.

Structural health monitoring and probability of detection estimation

Science.gov (United States)

Forsyth, David S.

2016-02-01

Structural health monitoring (SHM) methods are often based on nondestructive testing (NDT) sensors and are often proposed as replacements for NDT to lower cost and/or improve reliability. In order to take advantage of SHM for life cycle management, it is necessary to determine the Probability of Detection (POD) of the SHM system just as for traditional NDT to ensure that the required level of safety is maintained. Many different possibilities exist for SHM systems, but one of the attractive features of SHM versus NDT is the ability to take measurements very simply after the SHM system is installed. Using a simple statistical model of POD, some authors have proposed that very high rates of SHM system data sampling can result in high effective POD even in situations where an individual test has low POD. In this paper, we discuss the theoretical basis for determining the effect of repeated inspections, and examine data from SHM experiments against this framework to show how the effective POD from multiple tests can be estimated.

Development of a cost-effective and flexible vibration DAQ system for long-term continuous structural health monitoring

Science.gov (United States)

Nguyen, Theanh; Chan, Tommy H. T.; Thambiratnam, David P.; King, Les

2015-12-01

In the structural health monitoring (SHM) field, long-term continuous vibration-based monitoring is becoming increasingly popular as this could keep track of the health status of structures during their service lives. However, implementing such a system is not always feasible due to on-going conflicts between budget constraints and the need of sophisticated systems to monitor real-world structures under their demanding in-service conditions. To address this problem, this paper presents a comprehensive development of a cost-effective and flexible vibration DAQ system for long-term continuous SHM of a newly constructed institutional complex with a special focus on the main building. First, selections of sensor type and sensor positions are scrutinized to overcome adversities such as low-frequency and low-level vibration measurements. In order to economically tackle the sparse measurement problem, a cost-optimized Ethernet-based peripheral DAQ model is first adopted to form the system skeleton. A combination of a high-resolution timing coordination method based on the TCP/IP command communication medium and a periodic system resynchronization strategy is then proposed to synchronize data from multiple distributed DAQ units. The results of both experimental evaluations and experimental-numerical verifications show that the proposed DAQ system in general and the data synchronization solution in particular work well and they can provide a promising cost-effective and flexible alternative for use in real-world SHM projects. Finally, the paper demonstrates simple but effective ways to make use of the developed monitoring system for long-term continuous structural health evaluation as well as to use the instrumented building herein as a multi-purpose benchmark structure for studying not only practical SHM problems but also synchronization related issues.

Detecting delaminations and disbondings on full-scale wing composite panel by guided waves based SHM system

Science.gov (United States)

Monaco, E.; Boffa, N. D.; Memmolo, V.; Ricci, F.; Maio, L.

2016-04-01

A full-scale lower wing panel made of composite material has been designed, manufactured and sensorised within the European Funded research project named SARISTU. The authors contributed to the whole development of the system, from design to implementation as well as to the impacts campaign phase where Barely Visible and Visible Damages (BVID and VID) are to be artificially induced on the panel by a pneumatic impact machine. This work summarise part of the experimental results related to damages production, their assessment by C-SCAN as reference NDT method as well as damage detection of delimitations by a guided waves based SHM. The SHM system is made by customized piezoelectric patches secondary bonded on the wing plate acting both as guided waves sources and receivers. The paper will deal mostly with the experimental impact campaign and the signal analyses carried out to extract the metrics more sensitive to damages induced. Image reconstruction of the damages dimensions and shapes will be also described based mostly on the combination of metrics maps over the plate partial surfaces. Finally a comparison of damages maps obtained by the SHM approach and those obtained by "classic" C-SCAN will be presented analyzing briefly pros and cons of the two different approached as a combination to the most effective structural maintenance scenario of a commercial aircraft.

Assessing the value of structural health monitoring

DEFF Research Database (Denmark)

Thöns, S.; Faber, Michael Havbro

2013-01-01

Structural Health Monitoring (SHM) systems are designed for assisting owners and operators with information and forecasts concerning the fitness for purpose of structures and building systems. The benefit associated with the implementation of SHM may in some cases be intuitively anticipated...... as their responses and performances over their life-cycle. In addition, the quality of monitoring and the performance of possible remedial actions triggered by monitoring results are modeled probabilistically.The consequences accounted for, in principle include all consequences associated with the performance...

Direction-sensitive smart monitoring of structures using heterogeneous smartphone sensor data and coordinate system transformation

Science.gov (United States)

Ozer, Ekin; Feng, Maria Q.

2017-04-01

Mobile, heterogeneous, and smart sensor networks produce pervasive structural health monitoring (SHM) information. With various embedded sensors, smartphones have emerged to innovate SHM by empowering citizens to serve as sensors. By default, smartphones meet the fundamental smart sensor criteria, thanks to the built-in processor, memory, wireless communication units and mobile operating system. SHM using smartphones, however, faces technical challenges due to citizen-induced uncertainties, undesired sensor-structure integration, and lack of control over the sensing platform. Previously, the authors presented successful applications of smartphone accelerometers for structural vibration measurement and proposed a monitoring framework under citizen-induced spatiotemporal uncertainties. This study aims at extending the capabilities of smartphone-based SHM with a special focus on the lack of control over the sensor (i.e., the phone) positioning by citizens resulting in unknown sensor orientations. Using smartphone gyroscope, accelerometer, and magnetometer; instantaneous sensor orientation can be obtained with respect to gravitational and magnetic north directions. Using these sensor data, mobile operating system frameworks return processed features such as attitude and heading that can be used to correct misaligned sensor signals. For this purpose, a coordinate transformation procedure is proposed and illustrated on a two-story laboratory structural model and real-scale bridges with various sensor positioning examples. The proposed method corrects the sensor signals by tracking their orientations and improves measurement accuracy. Moreover, knowing structure’s coordinate system a priori, even the data from arbitrarily positioned sensors can automatically be transformed to the structural coordinates. In addition, this paper also touches some secondary mobile and heterogeneous data issues including imperfect sampling and geolocation services. The coordinate system

Fielding a structural health monitoring system on legacy military aircraft: A business perspective

Energy Technology Data Exchange (ETDEWEB)

Bos, Marcel J. [Dept. of Gas Turbines and Structural Integrity, National Aerospace Laboratory NLR, Amsterdam (Netherlands)

2015-12-15

An important trend in the sustainment of military aircraft is the transition from preventative maintenance to condition based maintenance (CBM). For CBM, it is essential that the actual system condition can be measured and the measured condition can be reliably extrapolated to a convenient moment in the future in order to facilitate the planning process while maintaining flight safety. Much research effort is currently being made for the development of technologies that enable CBM, including structural health monitoring (SHM) systems. Great progress has already been made in sensors, sensor networks, data acquisition, models and algorithms, data fusion/mining techniques, etc. However, the transition of these technologies into service is very slow. This is because business cases are difficult to define and the certification of the SHM systems is very challenging. This paper describes a possibility for fielding a SHM system on legacy military aircraft with a minimum amount of certification issues and with a good prospect of a positive return on investment. For appropriate areas in the airframe the application of SHM will reconcile the fail-safety and slow crack growth damage tolerance approaches that can be used for safeguarding the continuing airworthiness of these areas, combining the benefits of both approaches and eliminating the drawbacks.

Fielding a structural health monitoring system on legacy military aircraft: A business perspective

International Nuclear Information System (INIS)

Bos, Marcel J.

2015-01-01

An important trend in the sustainment of military aircraft is the transition from preventative maintenance to condition based maintenance (CBM). For CBM, it is essential that the actual system condition can be measured and the measured condition can be reliably extrapolated to a convenient moment in the future in order to facilitate the planning process while maintaining flight safety. Much research effort is currently being made for the development of technologies that enable CBM, including structural health monitoring (SHM) systems. Great progress has already been made in sensors, sensor networks, data acquisition, models and algorithms, data fusion/mining techniques, etc. However, the transition of these technologies into service is very slow. This is because business cases are difficult to define and the certification of the SHM systems is very challenging. This paper describes a possibility for fielding a SHM system on legacy military aircraft with a minimum amount of certification issues and with a good prospect of a positive return on investment. For appropriate areas in the airframe the application of SHM will reconcile the fail-safety and slow crack growth damage tolerance approaches that can be used for safeguarding the continuing airworthiness of these areas, combining the benefits of both approaches and eliminating the drawbacks

An Advanced Multi-Sensor Acousto-Ultrasonic Structural Health Monitoring System: Development and Aerospace Demonstration.

Science.gov (United States)

Smithard, Joel; Rajic, Nik; van der Velden, Stephen; Norman, Patrick; Rosalie, Cedric; Galea, Steve; Mei, Hanfei; Lin, Bin; Giurgiutiu, Victor

2017-07-20

A key longstanding objective of the Structural Health Monitoring (SHM) research community is to enable the embedment of SHM systems in high value assets like aircraft to provide on-demand damage detection and evaluation. As against traditional non-destructive inspection hardware, embedded SHM systems must be compact, lightweight, low-power and sufficiently robust to survive exposure to severe in-flight operating conditions. Typical Commercial-Off-The-Shelf (COTS) systems can be bulky, costly and are often inflexible in their configuration and/or scalability, which militates against in-service deployment. Advances in electronics have resulted in ever smaller, cheaper and more reliable components that facilitate the development of compact and robust embedded SHM systems, including for Acousto-Ultrasonics (AU), a guided plate-wave inspection modality that has attracted strong interest due mainly to its capacity to furnish wide-area diagnostic coverage with a relatively low sensor density. This article provides a detailed description of the development, testing and demonstration of a new AU interrogation system called the Acousto Ultrasonic Structural health monitoring Array Module⁺ (AUSAM⁺). This system provides independent actuation and sensing on four Piezoelectric Wafer Active Sensor (PWAS) elements with further sensing on four Positive Intrinsic Negative (PIN) photodiodes for intensity-based interrogation of Fiber Bragg Gratings (FBG). The paper details the development of a novel piezoelectric excitation amplifier, which, in conjunction with flexible acquisition-system architecture, seamlessly provides electromechanical impedance spectroscopy for PWAS diagnostics over the full instrument bandwidth of 50 KHz-5 MHz. The AUSAM⁺ functionality is accessed via a simple hardware object providing a myriad of custom software interfaces that can be adapted to suit the specific requirements of each individual application.

Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

Directory of Open Access Journals (Sweden)

You-Liang Ding

2015-01-01

Full Text Available Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge’s abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

Science.gov (United States)

Wu, Lai-Yi

2015-01-01

Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM) system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge's abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature. PMID:26451387

Fiber Bragg Grating Sensor System for Monitoring Smart Composite Aerospace Structures

Science.gov (United States)

Moslehi, Behzad; Black, Richard J.; Gowayed, Yasser

2012-01-01

Lightweight, electromagnetic interference (EMI) immune, fiber-optic, sensor- based structural health monitoring (SHM) will play an increasing role in aerospace structures ranging from aircraft wings to jet engine vanes. Fiber Bragg Grating (FBG) sensors for SHM include advanced signal processing, system and damage identification, and location and quantification algorithms. Potentially, the solution could be developed into an autonomous onboard system to inspect and perform non-destructive evaluation and SHM. A novel method has been developed to massively multiplex FBG sensors, supported by a parallel processing interrogator, which enables high sampling rates combined with highly distributed sensing (up to 96 sensors per system). The interrogation system comprises several subsystems. A broadband optical source subsystem (BOSS) and routing and interface module (RIM) send light from the interrogation system to a composite embedded FBG sensor matrix, which returns measurand-dependent wavelengths back to the interrogation system for measurement with subpicometer resolution. In particular, the returned wavelengths are channeled by the RIM to a photonic signal processing subsystem based on powerful optical chips, then passed through an optoelectronic interface to an analog post-detection electronics subsystem, digital post-detection electronics subsystem, and finally via a data interface to a computer. A range of composite structures has been fabricated with FBGs embedded. Stress tensile, bending, and dynamic strain tests were performed. The experimental work proved that the FBG sensors have a good level of accuracy in measuring the static response of the tested composite coupons (down to submicrostrain levels), the capability to detect and monitor dynamic loads, and the ability to detect defects in composites by a variety of methods including monitoring the decay time under different dynamic loading conditions. In addition to quasi-static and dynamic load monitoring, the

Monitoring of Engineering Buildings Behaviour Within the Disaster Management System

Science.gov (United States)

Oku Topal, G.; Gülal, E.

2017-11-01

The Disaster management aims to prevent events that result in disaster or to reduce their losses. Monitoring of engineering buildings, identification of unusual movements and taking the necessary precautions are very crucial for determination of the disaster risk so possible prevention could be taken to reduce big loss. Improving technology, increasing population due to increased construction and these areas largest economy lead to offer damage detection strategies. Structural Health Monitoring (SHM) is the most effective of these strategies. SHM research is very important to maintain all this structuring safely. The purpose of structural monitoring is determining in advance of possible accidents and taking necessary precaution. In this paper, determining the behaviour of construction using Global Positioning System (GPS) is investigated. For this purpose shaking table tests were performed. Shaking table was moved at different amplitude and frequency aiming to determine these movement with a GPS measuring system. The obtained data were evaluated by analysis of time series and Fast Fourier Transformation techniques and the frequency and amplitude values are calculated. By examining the results of the tests made, it will be determined whether the GPS measurement method can accurately detect the movements of the engineering structures.

Diseño e implementación de un sistema de adquisición y monitoreo de datos (shm para un rectificador de protección catódica usado en ductos.

Directory of Open Access Journals (Sweden)

Daniel Alejandro Rodríguez-Caro

2016-01-01

Full Text Available Background:Cathodic protection by impressed current is one of the methods to prevent corrosion of pipes or tanks, preserving the structural state and integrity of the material. For a cathodic protection system to function properly there must to be a control over the electrical variables involved in the process, which is why it is necessary to monitor variables such as (voltage, current and potential protection. Objective: to develop a system of data acquisition and monitoring in real time, in order to increase accessibility to electrical variables and thus improve the operation of the cathodic protection system. Methods: The monitoring and information analysis system is based on the concept of SHM (Structural Health Monitoring, which consists of an electronic system for remote acquisition and sending of signals (micro controller and GSM communications system and a system for visualization and analysis of information in a mobile system (cell using a web server for it. Given that the condition of structural integrity of the pipeline is determined by the correct operation of the rectifier. Results: It was possible to implement a monitoring and remote viewing system of the main variables of a cathodic protection system. An algorithm based on the concept of SHM was developed, allowing to correlate, generate trend and establish performance criteria for the cathodic protection system which allows to establish whether the system is ensuring the structural integrity of the crude transportation pipeline. Conclusion: the novelty of this work is to show the real-time behavior of the variables needed to analyze whether the pipeline is being properly protected and generate alarms and reports regarding cathodic protection, which is based on the concept of SHM (Structural Health Monitoring.

NDE and SHM Simulation for CFRP Composites

Science.gov (United States)

Leckey, Cara A. C.; Parker, F. Raymond

2014-01-01

Ultrasound-based nondestructive evaluation (NDE) is a common technique for damage detection in composite materials. There is a need for advanced NDE that goes beyond damage detection to damage quantification and characterization in order to enable data driven prognostics. The damage types that exist in carbon fiber-reinforced polymer (CFRP) composites include microcracking and delaminations, and can be initiated and grown via impact forces (due to ground vehicles, tool drops, bird strikes, etc), fatigue, and extreme environmental changes. X-ray microfocus computed tomography data, among other methods, have shown that these damage types often result in voids/discontinuities of a complex volumetric shape. The specific damage geometry and location within ply layers affect damage growth. Realistic threedimensional NDE and structural health monitoring (SHM) simulations can aid in the development and optimization of damage quantification and characterization techniques. This paper is an overview of ongoing work towards realistic NDE and SHM simulation tools for composites, and also discusses NASA's need for such simulation tools in aeronautics and spaceflight. The paper describes the development and implementation of a custom ultrasound simulation tool that is used to model ultrasonic wave interaction with realistic 3-dimensional damage in CFRP composites. The custom code uses elastodynamic finite integration technique and is parallelized to run efficiently on computing cluster or multicore machines.

Design of overload vehicle monitoring and response system based on DSP

Science.gov (United States)

Yu, Yan; Liu, Yiheng; Zhao, Xuefeng

2014-03-01

The overload vehicles are making much more damage to the road surface than the regular ones. Many roads and bridges are equipped with structural health monitoring system (SHM) to provide early-warning to these damage and evaluate the safety of road and bridge. However, because of the complex nature of SHM system, it's expensive to manufacture, difficult to install and not well-suited for the regular bridges and roads. Based on this application background, this paper designs a compact structural health monitoring system based on DSP, which is highly integrated, low-power, easy to install and inexpensive to manufacture. The designed system is made up of sensor arrays, the charge amplifier module, the DSP processing unit, the alarm system for overload, and the estimate for damage of the road and bridge structure. The signals coming from sensor arrays go through the charge amplifier. DSP processing unit will receive the amplified signals, estimate whether it is an overload signal or not, and convert analog variables into digital ones so that they are compatible with the back-end digital circuit for further processing. The system will also restrict certain vehicles that are overweight, by taking image of the car brand, sending the alarm, and transferring the collected pressure data to remote data center for further monitoring analysis by rain-flow counting method.

Smart Sensing Technologies for Structural Health Monitoring of Civil Engineering Structures

OpenAIRE

M. Sun; W. J. Staszewski; R. N. Swamy

2010-01-01

Structural Health Monitoring (SHM) aims to develop automated systems for the continuous monitoring, inspection, and damage detection of structures with minimum labour involvement. The first step to set up a SHM system is to incorporate a level of structural sensing capability that is reliable and possesses long term stability. Smart sensing technologies including the applications of fibre optic sensors, piezoelectric sensors, magnetostrictive sensors and self-diagnosing fibre reinforced compo...

Development of a structural health monitoring system for the life assessment of critical transportation infrastructure.

Energy Technology Data Exchange (ETDEWEB)

Roach, Dennis Patrick; Jauregui, David Villegas (New Mexico State University, Las Cruces, NM); Daumueller, Andrew Nicholas (New Mexico State University, Las Cruces, NM)

2012-02-01

Recent structural failures such as the I-35W Mississippi River Bridge in Minnesota have underscored the urgent need for improved methods and procedures for evaluating our aging transportation infrastructure. This research seeks to develop a basis for a Structural Health Monitoring (SHM) system to provide quantitative information related to the structural integrity of metallic structures to make appropriate management decisions and ensuring public safety. This research employs advanced structural analysis and nondestructive testing (NDT) methods for an accurate fatigue analysis. Metal railroad bridges in New Mexico will be the focus since many of these structures are over 100 years old and classified as fracture-critical. The term fracture-critical indicates that failure of a single component may result in complete collapse of the structure such as the one experienced by the I-35W Bridge. Failure may originate from sources such as loss of section due to corrosion or cracking caused by fatigue loading. Because standard inspection practice is primarily visual, these types of defects can go undetected due to oversight, lack of access to critical areas, or, in riveted members, hidden defects that are beneath fasteners or connection angles. Another issue is that it is difficult to determine the fatigue damage that a structure has experienced and the rate at which damage is accumulating due to uncertain history and load distribution in supporting members. A SHM system has several advantages that can overcome these limitations. SHM allows critical areas of the structure to be monitored more quantitatively under actual loading. The research needed to apply SHM to metallic structures was performed and a case study was carried out to show the potential of SHM-driven fatigue evaluation to assess the condition of critical transportation infrastructure and to guide inspectors to potential problem areas. This project combines the expertise in transportation infrastructure at New

Technical Specifications of Structural Health Monitoring for Highway Bridges: New Chinese Structural Health Monitoring Code

Directory of Open Access Journals (Sweden)

Fernando Moreu

2018-03-01

Full Text Available Governments and professional groups related to civil engineering write and publish standards and codes to protect the safety of critical infrastructure. In recent decades, countries have developed codes and standards for structural health monitoring (SHM. During this same period, rapid growth in the Chinese economy has led to massive development of civil engineering infrastructure design and construction projects. In 2016, the Ministry of Transportation of the People’s Republic of China published a new design code for SHM systems for large highway bridges. This document is the first technical SHM code by a national government that enforces sensor installation on highway bridges. This paper summarizes the existing international technical SHM codes for various countries and compares them with the new SHM code required by the Chinese Ministry of Transportation. This paper outlines the contents of the new Chinese SHM code and explains its relevance for the safety and management of large bridges in China, introducing key definitions of the Chinese–United States SHM vocabulary and their technical significance. Finally, this paper discusses the implications for the design and implementation of a future SHM codes, with suggestions for similar efforts in United States and other countries.

Investigation of an expert health monitoring system for aeronautical structures based on pattern recognition and acousto-ultrasonics

Science.gov (United States)

Tibaduiza-Burgos, Diego Alexander; Torres-Arredondo, Miguel Angel

2015-08-01

Aeronautical structures are subjected to damage during their service raising the necessity for periodic inspection and maintenance of their components so that structural integrity and safe operation can be guaranteed. Cost reduction related to minimizing the out-of-service time of the aircraft, together with the advantages offered by real-time and safe-life service monitoring, have led to a boom in the design of inexpensive and structurally integrated transducer networks comprising actuators, sensors, signal processing units and controllers. These kinds of automated systems are normally referred to as smart structures and offer a multitude of new solutions to engineering problems and multi-functional capabilities. It is thus expected that structural health monitoring (SHM) systems will become one of the leading technologies for assessing and assuring the structural integrity of future aircraft. This study is devoted to the development and experimental investigation of an SHM methodology for the detection of damage in real scale complex aeronautical structures. The work focuses on each aspect of the SHM system and highlights the potentialities of the health monitoring technique based on acousto-ultrasonics and data-driven modelling within the concepts of sensor data fusion, feature extraction and pattern recognition. The methodology is experimentally demonstrated on an aircraft skin panel and fuselage panel for which several damage scenarios are analysed. The detection performance in both structures is quantified and presented.

A review on bridge dynamic displacement monitoring using global positioning system and accelerometer

Science.gov (United States)

Yunus, Mohd Zulkifli Mohd; Ibrahim, Nuremira; Ahmad, Fatimah Shafinaz

2018-02-01

This paper reviews previous research on bridge dynamic displacement monitoring using Global Positioning System (GPS) and an accelerometer for Structural Health Monitoring (SHM) of bridge. These include the review of the advantages and disadvantages of the measurement as well as the methodology of the measurements used in the recent research study. This review could provide a preliminary decision overview for students or researchers before initiating a research related to the bridge dynamic displacement monitoring.

Review of Radio Frequency Identification and Wireless Technology for Structural Health Monitoring

Energy Technology Data Exchange (ETDEWEB)

Dhital, Dipesh; Chia, Chen Ciang; Lee, Jung Ryul [Chonbuk National University, Jeonju (Korea, Republic of); Park, Chan Yik [Aeronautical Technology Directorate, Agency for Defense Development, Daejeon (Korea, Republic of)

2010-06-15

Radio frequency identification(RFID) combined with wireless technology has good potential for structural health monitoring(SHM). We describe several advantages of RFID and wireless technologies for SHM, and review SHM examples with working principles, design and technical details for damage detection, heat exposure monitoring, force/strain sensing, and corrosion detection in concrete, steel, carbon fiber reinforced polymer(CFRP), and other materials. Various sensors combined with wireless communication are also discussed. These methodologies can be readily developed, implemented, and customized. There are some technical difficulties, but solutions are being addressed. Lastly, a surface acoustic wave-based RFID system is presented, and possible future trends of SHM based on RFID and wireless technology are presented

Review of Radio Frequency Identification and Wireless Technology for Structural Health Monitoring

International Nuclear Information System (INIS)

Dhital, Dipesh; Chia, Chen Ciang; Lee, Jung Ryul; Park, Chan Yik

2010-01-01

Radio frequency identification(RFID) combined with wireless technology has good potential for structural health monitoring(SHM). We describe several advantages of RFID and wireless technologies for SHM, and review SHM examples with working principles, design and technical details for damage detection, heat exposure monitoring, force/strain sensing, and corrosion detection in concrete, steel, carbon fiber reinforced polymer(CFRP), and other materials. Various sensors combined with wireless communication are also discussed. These methodologies can be readily developed, implemented, and customized. There are some technical difficulties, but solutions are being addressed. Lastly, a surface acoustic wave-based RFID system is presented, and possible future trends of SHM based on RFID and wireless technology are presented

Load monitoring of aerospace structures utilizing micro-electro-mechanical systems for static and quasi-static loading conditions

International Nuclear Information System (INIS)

Martinez, M; Rocha, B; Li, M; Shi, G; Beltempo, A; Rutledge, R; Yanishevsky, M

2012-01-01

The National Research Council Canada (NRC) has worked on the development of structural health monitoring (SHM) test platforms for assessing the performance of sensor systems for load monitoring applications. The first SHM platform consists of a 5.5 m cantilever aluminum beam that provides an optimal scenario for evaluating the ability of a load monitoring system to measure bending, torsion and shear loads. The second SHM platform contains an added level of structural complexity, by consisting of aluminum skins with bonded/riveted stringers, typical of an aircraft lower wing structure. These two load monitoring platforms are well characterized and documented, providing loading conditions similar to those encountered during service. In this study, a micro-electro-mechanical system (MEMS) for acquiring data from triads of gyroscopes, accelerometers and magnetometers is described. The system was used to compute changes in angles at discrete stations along the platforms. The angles obtained from the MEMS were used to compute a second, third or fourth order degree polynomial surface from which displacements at every point could be computed. The use of a new Kalman filter was evaluated for angle estimation, from which displacements in the structure were computed. The outputs of the newly developed algorithms were then compared to the displacements obtained from the linear variable displacement transducers connected to the platforms. The displacement curves were subsequently post-processed either analytically, or with the help of a finite element model of the structure, to estimate strains and loads. The estimated strains were compared with baseline strain gauge instrumentation installed on the platforms. This new approach for load monitoring was able to provide accurate estimates of applied strains and shear loads. (paper)

Principles in wireless building health monitoring systems.

Science.gov (United States)

Pentaris, F. P.; Makris, J. P.; Stonham, J.; Vallianatos, F.

2012-04-01

Monitoring the structural state of a building is essential for the safety of the people who work, live, visit or just use it as well as for the civil protection of urban areas. Many factors can affect the state of the health of a structure, namely man made, like mistakes in the construction, traffic, heavy loads on the structures, explosions, environmental impacts like wind loads, humidity, chemical reactions, temperature changes and saltiness, and natural hazards like earthquakes and landslides. Monitoring the health of a structure provides the ability to anticipate structural failures and secure the safe use of buildings especially those of public services. This work reviews the state of the art and the challenges of a wireless Structural Health Monitoring (WiSHM). Literature review reveals that although there is significant evolution in wireless structural health monitoring, in many cases, monitoring by itself is not enough to predict when a structure becomes inappropriate and/or unsafe for use, and the damage or low durability of a structure cannot be revealed (Chintalapudi, et al., 2006; Ramos, Aguilar, & Lourenço, 2011). Several features and specifications of WiSHM like wireless sensor networking, reliability and autonomy of sensors, algorithms of data transmission and analysis should still be evolved and improved in order to increase the predictive effectiveness of the SHM (Jinping Ou & Hui Li, 2010; Lu & Loh, 2010) . Acknowledgments This work was supported in part by the ARCHEMEDES III Program of the Ministry of Education of Greece and the European Union in the framework of the project entitled «Interdisciplinary Multi-Scale Research of Earthquake Physics and Seismotectonics at the front of the Hellenic Arc (IMPACT-ARC) ».

Wireless sensor networks for structural health monitoring

CERN Document Server

Cao, Jiannong

2016-01-01

This brief covers the emerging area of wireless sensor network (WSN)-based structural health monitoring (SHM) systems, and introduces the authors’ WSN-based platform called SenetSHM. It helps the reader differentiate specific requirements of SHM applications from other traditional WSN applications, and demonstrates how these requirements are addressed by using a series of systematic approaches. The brief serves as a practical guide, explaining both the state-of-the-art technologies in domain-specific applications of WSNs, as well as the methodologies used to address the specific requirements for a WSN application. In particular, the brief offers instruction for problem formulation and problem solving based on the authors’ own experiences implementing SenetSHM. Seven concise chapters cover the development of hardware and software design of SenetSHM, as well as in-field experiments conducted while testing the platform. The brief’s exploration of the SenetSHM platform is a valuable feature for civil engine...

Combining model based and data based techniques in a robust bridge health monitoring algorithm.

Science.gov (United States)

2014-09-01

Structural Health Monitoring (SHM) aims to analyze civil, mechanical and aerospace systems in order to assess : incipient damage occurrence. In this project, we are concerned with the development of an algorithm within the : SHM paradigm for applicat...

Wireless Impedance-Based SHM for Bolted Connections via Multiple PZT-Interfaces

International Nuclear Information System (INIS)

Nguyen, Khac Duy; Kim, Jeong Tae

2011-01-01

This study presents a structural health monitoring(SHM) method for bolted connections by using multi-channel wireless impedance sensor nodes and multiple PZT-interfaces. To achieve the objective, the following approaches are implemented. Firstly, a PZT-interface is designed to monitor bolt loosening in bolted connection based on variation of electro-mechanical(EM) impedance signatures. Secondly, a wireless impedance sensor node is designed for autonomous, cost-efficient and multi-channel monitoring. For the sensor platform, Imote2 is selected on the basis of its high operating speed, low power requirement and large storage memory. Finally, the performance of the wireless sensor node and the PZT-interfaces is experimentally evaluated for a bolt-connection model. Damage monitoring method using root mean square deviation(RMSD) index of EM impedance signatures is utilized to estimate the strength of the bolted joint

Structural health monitoring 2012. Proceedings. Vol. 2

International Nuclear Information System (INIS)

Boller, Christian

2012-01-01

Structural Health Monitoring (SHM) is an emerging technology, dealing with the development and implementation of techniques and systems where monitoring, inspection and damage detection become an integral part of structures and thus a matter of automation. It further merges with a variety of techniques related to diagnostics and prognostics. SHM emerged from the field of smart structures and laterally encompasses disciplines such as structural dynamics, materials and structures, fatigue and fracture, non-destructive testing and evaluation, sensors and actuators, microelectronics, signal processing and much more. To be effective in the development of SHM systems, a multidisciplinary approach is therefore required. Without this global view it will be difficult for engineers to holistically manage the operation of an engineering structure through its life cycle in the future and to generate new breakthroughs in structural engineering. The second volume of the proceedings contains topics dealing with applications in the field of aeronautics, astronautic, civil engineering (bridges), energy (wind power), structural health monitoring (transportation), and poster presentations. Ten of the contributions are separately analyzed for the ENERGY database.

Aspects of structural health and condition monitoring of offshore wind turbines.

Science.gov (United States)

Antoniadou, I; Dervilis, N; Papatheou, E; Maguire, A E; Worden, K

2015-02-28

Wind power has expanded significantly over the past years, although reliability of wind turbine systems, especially of offshore wind turbines, has been many times unsatisfactory in the past. Wind turbine failures are equivalent to crucial financial losses. Therefore, creating and applying strategies that improve the reliability of their components is important for a successful implementation of such systems. Structural health monitoring (SHM) addresses these problems through the monitoring of parameters indicative of the state of the structure examined. Condition monitoring (CM), on the other hand, can be seen as a specialized area of the SHM community that aims at damage detection of, particularly, rotating machinery. The paper is divided into two parts: in the first part, advanced signal processing and machine learning methods are discussed for SHM and CM on wind turbine gearbox and blade damage detection examples. In the second part, an initial exploration of supervisor control and data acquisition systems data of an offshore wind farm is presented, and data-driven approaches are proposed for detecting abnormal behaviour of wind turbines. It is shown that the advanced signal processing methods discussed are effective and that it is important to adopt these SHM strategies in the wind energy sector.

Aspects of structural health and condition monitoring of offshore wind turbines

Science.gov (United States)

Antoniadou, I.; Dervilis, N.; Papatheou, E.; Maguire, A. E.; Worden, K.

2015-01-01

Wind power has expanded significantly over the past years, although reliability of wind turbine systems, especially of offshore wind turbines, has been many times unsatisfactory in the past. Wind turbine failures are equivalent to crucial financial losses. Therefore, creating and applying strategies that improve the reliability of their components is important for a successful implementation of such systems. Structural health monitoring (SHM) addresses these problems through the monitoring of parameters indicative of the state of the structure examined. Condition monitoring (CM), on the other hand, can be seen as a specialized area of the SHM community that aims at damage detection of, particularly, rotating machinery. The paper is divided into two parts: in the first part, advanced signal processing and machine learning methods are discussed for SHM and CM on wind turbine gearbox and blade damage detection examples. In the second part, an initial exploration of supervisor control and data acquisition systems data of an offshore wind farm is presented, and data-driven approaches are proposed for detecting abnormal behaviour of wind turbines. It is shown that the advanced signal processing methods discussed are effective and that it is important to adopt these SHM strategies in the wind energy sector. PMID:25583864

Structural health monitoring 2012. Proceedings. Vol. 1

International Nuclear Information System (INIS)

Boller, Christian

2012-01-01

Structural Health Monitoring (SHM) is an emerging technology, dealing with the development and implementation of techniques and systems where monitoring, inspection and damage detection become an integral part of structures and thus a matter of automation. It further merges with a variety of techniques related to diagnostics and prognostics. SHM emerged from the field of smart structures and laterally encompasses disciplines such as structural dynamics, materials and structures, fatigue and fracture, non-destructive testing and evaluation, sensors and actuators, microelectronics, signal processing and much more. To be effective in the development of SHM systems, a multidisciplinary approach is therefore required. Without this global view it will be difficult for engineers to holistically manage the operation of an engineering structure through its life cycle in the future and to generate new breakthroughs in structural engineering. The first volume of the proceedings contains topics dealing with physics, materials and sensors. Five of the contributions are separately analyzed for the ENERGY database.

Integrating structural health and condition monitoring

DEFF Research Database (Denmark)

May, Allan; Thöns, Sebastian; McMillan, David

2015-01-01

window’ allowing for the possible detection of faults up to 6 months in advance. The SHM system model uses a reduction in the probability of failure factor to account for lower modelling uncertainties. A case study is produced that shows a reduction in operating costs and also a reduction in risk......There is a large financial incentive to minimise operations and maintenance (O&M) costs for offshore wind power by optimising the maintenance plan. The integration of condition monitoring (CM) and structural health monitoring (SHM) may help realise this. There is limited work on the integration...

Three-Dimensional Health Monitoring of Sandwich Composites, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This SBIR project delivers a single-chip structural health-monitoring (SHM) system that uses the impedance method to monitor bulk interiors and wave propagation...

Structural health monitoring (vibration) as a tool for identifying structural alterations of the lumbar spine

DEFF Research Database (Denmark)

Kawchuk, Gregory N; Hartvigsen, Jan; Edgecombe, Tiffany

2016-01-01

Structural health monitoring (SHM) is an engineering technique used to identify mechanical abnormalities not readily apparent through other means. Recently, SHM has been adapted for use in biological systems, but its invasive nature limits its clinical application. As such, the purpose of this pr......Structural health monitoring (SHM) is an engineering technique used to identify mechanical abnormalities not readily apparent through other means. Recently, SHM has been adapted for use in biological systems, but its invasive nature limits its clinical application. As such, the purpose...... of this project was to determine if a non-invasive form of SHM could identify structural alterations in the spines of living human subjects. Lumbar spines of 10 twin pairs were visualized by magnetic resonance imaging then assessed by a blinded radiologist to determine whether twin pairs were structurally...... concordant or discordant. Vibration was then applied to each subject's spine and the resulting response recorded from sensors overlying lumbar spinous processes. The peak frequency, area under the curve and the root mean square were computed from the frequency response function of each sensor. Statistical...

On the Value of Structural Health Monitoring Information for the Operation of Wind Parks

DEFF Research Database (Denmark)

Thöns, Sebastian; Faber, Michael H.; Val, Dimitri V.

2017-01-01

wind turbine systems and its components is developed accounting for the wind park functionality, i.e. power production, its operation and its cascading damage and failure scenarios. This system model facilitates to quantify the expected benefits and risks throughout the service life accounting......In the present paper, an approach for the quantification of the Value of Structural Health Monitoring (SHM) Information building upon a framework for infrastructure system utility and decision analysis is developed and applied to the operation of wind parks. The quantification of the value of SHM...... facilitates a benefit and risk informed assessment and optimization of SHM strategies and encompasses models for the infrastructure functionality, the structural constituent and system risks and its management as well as the performance of SHM strategies. A wind park system model incorporating the structural...

Guided Waves in Structures for SHM The Time - domain Spectral Element Method

CERN Document Server

Ostachowicz, Wieslaw; Krawczuk, Marek; Zak, Arkadiusz

2011-01-01

Presents the state of the art in the modelling, analysis and experimental investigation of elastic wave propagation using a technique of rapidly increasing interest and development Addressing an important issue in the field of guided-wave-based damage identification and structural health monitoring,Guided Waves in Structures for SHM presents the modelling, analysis and experimental investigation of elastic wave propagation in engineering structures made of isotropic or composite materials. The authors begin by summarising present-day knowledge on elastic wave propagation in solids, focusing on

Energy Harvesting for Structural Health Monitoring Sensor Networks

Energy Technology Data Exchange (ETDEWEB)

Park, G.; Farrar, C. R.; Todd, M. D.; Hodgkiss, T.; Rosing, T.

2007-02-26

This report has been developed based on information exchanges at a 2.5-day workshop on energy harvesting for embedded structural health monitoring (SHM) sensing systems that was held June 28-30, 2005, at Los Alamos National Laboratory. The workshop was hosted by the LANL/UCSD Engineering Institute (EI). This Institute is an education- and research-focused collaboration between Los Alamos National Laboratory (LANL) and the University of California, San Diego (UCSD), Jacobs School of Engineering. A Statistical Pattern Recognition paradigm for SHM is first presented and the concept of energy harvesting for embedded sensing systems is addressed with respect to the data acquisition portion of this paradigm. Next, various existing and emerging sensing modalities used for SHM and their respective power requirements are summarized, followed by a discussion of SHM sensor network paradigms, power requirements for these networks and power optimization strategies. Various approaches to energy harvesting and energy storage are discussed and limitations associated with the current technology are addressed. This discussion also addresses current energy harvesting applications and system integration issues. The report concludes by defining some future research directions and possible technology demonstrations that are aimed at transitioning the concept of energy harvesting for embedded SHM sensing systems from laboratory research to field-deployed engineering prototypes.

Life-Cycle Monitoring of Long-Span PSC Box Girder Bridges through Distributed Sensor Network: Strategies, Methods, and Applications

Directory of Open Access Journals (Sweden)

Zheheng Chen

2015-01-01

Full Text Available Structural health monitoring (SHM has attracted much attention in recent years, which enables early warnings of structural failure, condition assessments, and rational maintenance/repair strategies. In the context of bridges, many long-span steel bridges in China have been installed with the SHM systems; however, the applications of the SHM in prestressed concrete (PSC bridges are still rather limited. On the other hand, the PSC box girder bridges are extensively used in highway and railway systems and premature damage of these bridges is often reported, resulting in considerable maintenance and/or replacement costs. First, this paper presents a state-of-art review on the SHM of long-span PSC bridges. Monitoring strategies, methods, and previous applications for these bridges are summarized and discussed. In order to well capture the behavior of the bridge during its whole life and to maximize the use of sensors, a life-cycle monitoring strategy is proposed, in which the sensor layout is determined according to requirements for construction monitoring, completion test, and in-service monitoring. A case study is made on a three-span PSC box girder bridge in China. The system configuration, sensor layout, and data communications, and so forth, are presented. The up-to-date monitored structural responses are analyzed and compared with the design values.

Embedded Active Fiber Optic Sensing Network for Structural Health Monitoring in Harsh Environments

Energy Technology Data Exchange (ETDEWEB)

Wang, Anbo [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

2016-09-30

This report summarizes technical progress on the program “Embedded Active Fiber Optic Sensing Network for Structural Health Monitoring in Harsh Environments” funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Center for Photonics Technology at Virginia Tech. The objective of this project is to develop a first-of-a-kind technology for remote fiber optic generation and detection of acoustic waves for structural health monitoring in harsh environments. During the project period, which is from April 1, 2013 to Septemeber 30, 2016, three different acoustic generation mechanisms were studied in detail for their applications in building a fiber optic acoustic generation unit (AGU), including laser induced plasma breakdown (LIP), Erbium-doped fiber laser absorption, and metal laser absorption. By comparing the performance of the AGUs designed based on these three mechanisms and analyzing the experimental results with simulations, the metal laser absorption method was selected to build a complete fiber optic structure health monitoring (FO-SHM) system for the proposed high temperature multi-parameter structure health monitoring application. Based on the simulation of elastic wave propagation and fiber Bragg grating acoustic pulse detection, an FO-SHM element together with a completed interrogation system were designed and built. This system was first tested on an aluminum piece in the low-temperature range and successfully demonstrated its capability of multi-parameter monitoring and multi-point sensing. In the later stages of the project, the research was focused on improving the surface attachment design and preparing the FO-SHM element for high temperature environment tests. After several upgrades to the surface attachment methods, the FO-SHM element was able to work reliably up to 600oC when attached to P91 pipes, which are the target material of this project. In the final stage of this project, this FO-SHM

Monitoring of structures: review of technologies

International Nuclear Information System (INIS)

2013-01-01

Structural Health Monitoring (SHM) aims at monitoring the integrity of structures either in a continuous way or periodically. SHM is used for the monitoring of big civil works like bridges, dams, railways or critical structures like nuclear power plants or chemical plants. The sensors fixed on the structure allow an in-service monitoring. SHM gathers various technologies like ultrasound, acoustic emission, vibrations, Foucault currents...A technology based on guided ultrasonic waves (Lamb waves) appears promising for monitoring large structures made of composite materials. Another technology based on optical fibers can be used in very harsh environment and the optic fiber does not require any more sensors, the optical fiber itself being the sensor. The optical fiber is generally integrated to the structure during the construction phase. (A.C.)

Progress of the COST Action TU1402 on the Quantification of the Value of Structural Health Monitoring

DEFF Research Database (Denmark)

Thöns, Sebastian; Limongelli, Maria Pina; Ivankovic, Ana Mandic

2017-01-01

This paper summarizes the development of Value of Structural Health Monitoring (SHM) Information analyses and introduces the development, objectives and approaches of the COST Action TU1402 on this topic. SHM research and engineering has been focused on the extraction of loading, degradation...... for its quantification. This challenge can be met with Value of SHM Information analyses facilitating that the SHM contribution to substantial benefits for life safety, economy and beyond can be may be quantified, demonstrated and utilized. However, Value of SHM Information analyses involve complex models...... encompassing the infrastructure and the SHM systems, their functionality and thus require the interaction of several research disciplines. For progressing on these points, a scientific networking and dissemination project namely the COST Action TU1402 has been initiated....

Genetic fuzzy system for online structural health monitoring of composite helicopter rotor blades

Science.gov (United States)

Pawar, Prashant M.; Ganguli, Ranjan

2007-07-01

A structural health monitoring (SHM) methodology is developed for composite rotor blades. An aeroelastic analysis of composite rotor blades based on the finite element method in space and time and with implanted matrix cracking and debonding/delamination damage is used to obtain measurable system parameters such as blade response, loads and strains. A rotor blade with a two-cell airfoil section and [0/±45/90]s family of laminates is used for numerical simulations. The model based measurements are contaminated with noise to simulate real data. Genetic fuzzy systems (GFS) are developed for global online damage detection using displacement and force-based measurement deviations between damaged and undamaged conditions and for local online damage detection using strains. It is observed that the success rate of the GFS depends on number of measurements, type of measurements and training and testing noise level. The GFS work quite well with noisy data and is recommended for online SHM of composite helicopter rotor blades.

Review on energy harvesting for structural health monitoring in aeronautical applications

Science.gov (United States)

Le, Minh Quyen; Capsal, Jean-Fabien; Lallart, Mickaël; Hebrard, Yoann; Van Der Ham, Andre; Reffe, Nicolas; Geynet, Lionel; Cottinet, Pierre-Jean

2015-11-01

This paper reviews recent developments in energy harvesting technologies for structural health monitoring (SHM) in aeronautical applications. Aeronautical industries show a great deal of interest in obtaining technologies that can be used to monitor the health of machinery and structures. In particular, the need for self-sufficient monitoring of structures has been ever-increasing in recent years. Autonomous SHM systems typically include embedded sensors, and elements for data acquisition, wireless communication, and energy harvesting. Among all of these components, this paper focuses on energy harvesting technologies. Actually, low-power sensors and wireless communication components are used in newer SHM systems, and a number of researchers have recently investigated such techniques to extract energy from the local environment to power these stand-alone systems. The first part of the paper is dedicated to the different energy sources available in aeronautical applications, i.e., for airplanes and helicopters. The second part gives a presentation of the various devices developed for converting ambient energy into electric power. The last part is dedicated to a comparison of the different technologies and the future development of energy harvesting for aeronautical applications.

Life-Cycle Monitoring of Long-Span PSC Box Girder Bridges through Distributed Sensor Network: Strategies, Methods, and Applications

OpenAIRE

Chen, Zheheng; Guo, Tong; Yan, Shengyou

2015-01-01

Structural health monitoring (SHM) has attracted much attention in recent years, which enables early warnings of structural failure, condition assessments, and rational maintenance/repair strategies. In the context of bridges, many long-span steel bridges in China have been installed with the SHM systems; however, the applications of the SHM in prestressed concrete (PSC) bridges are still rather limited. On the other hand, the PSC box girder bridges are extensively used in highway and railway...

Integration of High-Resolution Laser Displacement Sensors and 3D Printing for Structural Health Monitoring

Directory of Open Access Journals (Sweden)

Shu-Wei Chang

2017-12-01

Full Text Available This paper presents a novel experimental design for complex structural health monitoring (SHM studies achieved by integrating 3D printing technologies, high-resolution laser displacement sensors, and multiscale entropy SHM theory. A seven-story structure with a variety of composite bracing systems was constructed using a dual-material 3D printer. A wireless Bluetooth vibration speaker was used to excite the ground floor of the structure, and high-resolution laser displacement sensors (1-μm resolution were used to monitor the displacement history on different floors. Our results showed that the multiscale entropy SHM method could detect damage on the 3D-printed structures. The results of this study demonstrate that integrating 3D printing technologies and high-resolution laser displacement sensors enables the design of cheap, fast processing, complex, small-scale civil structures for future SHM studies. The novel experimental design proposed in this study provides a suitable platform for investigating the validity and sensitivity of SHM in different composite structures and damage conditions for real life applications in the future.

Integration of High-Resolution Laser Displacement Sensors and 3D Printing for Structural Health Monitoring.

Science.gov (United States)

Chang, Shu-Wei; Lin, Tzu-Kang; Kuo, Shih-Yu; Huang, Ting-Hsuan

2017-12-22

This paper presents a novel experimental design for complex structural health monitoring (SHM) studies achieved by integrating 3D printing technologies, high-resolution laser displacement sensors, and multiscale entropy SHM theory. A seven-story structure with a variety of composite bracing systems was constructed using a dual-material 3D printer. A wireless Bluetooth vibration speaker was used to excite the ground floor of the structure, and high-resolution laser displacement sensors (1-μm resolution) were used to monitor the displacement history on different floors. Our results showed that the multiscale entropy SHM method could detect damage on the 3D-printed structures. The results of this study demonstrate that integrating 3D printing technologies and high-resolution laser displacement sensors enables the design of cheap, fast processing, complex, small-scale civil structures for future SHM studies. The novel experimental design proposed in this study provides a suitable platform for investigating the validity and sensitivity of SHM in different composite structures and damage conditions for real life applications in the future.

Recent Developments on Wireless Sensor Networks Technology for Bridge Health Monitoring

Directory of Open Access Journals (Sweden)

Guang-Dong Zhou

2013-01-01

Full Text Available Structural health monitoring (SHM systems have shown great potential to sense the responses of a bridge system, diagnose the current structural conditions, predict the expected future performance, provide information for maintenance, and validate design hypotheses. Wireless sensor networks (WSNs that have the benefits of reducing implementation costs of SHM systems as well as improving data processing efficiency become an attractive alternative to traditional tethered sensor systems. This paper introduces recent technology developments in the field of bridge health monitoring using WSNs. As a special application of WSNs, the requirements and characteristics of WSNs when used for bridge health monitoring are firstly briefly discussed. Then, the state of the art in WSNs-based bridge health monitoring systems is reviewed including wireless sensor, network topology, data processing technology, power management, and time synchronization. Following that, the performance validations and applications of WSNs in bridge health monitoring through scale models and field deployment are presented. Finally, some existing problems and promising research efforts for promoting applications of WSNs technology in bridge health monitoring throughout the world are explored.

A distributed cloud-based cyberinfrastructure framework for integrated bridge monitoring

Science.gov (United States)

Jeong, Seongwoon; Hou, Rui; Lynch, Jerome P.; Sohn, Hoon; Law, Kincho H.

2017-04-01

This paper describes a cloud-based cyberinfrastructure framework for the management of the diverse data involved in bridge monitoring. Bridge monitoring involves various hardware systems, software tools and laborious activities that include, for examples, a structural health monitoring (SHM), sensor network, engineering analysis programs and visual inspection. Very often, these monitoring systems, tools and activities are not coordinated, and the collected information are not shared. A well-designed integrated data management framework can support the effective use of the data and, thereby, enhance bridge management and maintenance operations. The cloud-based cyberinfrastructure framework presented herein is designed to manage not only sensor measurement data acquired from the SHM system, but also other relevant information, such as bridge engineering model and traffic videos, in an integrated manner. For the scalability and flexibility, cloud computing services and distributed database systems are employed. The information stored can be accessed through standard web interfaces. For demonstration, the cyberinfrastructure system is implemented for the monitoring of the bridges located along the I-275 Corridor in the state of Michigan.

Structural health monitoring feature design by genetic programming

International Nuclear Information System (INIS)

Harvey, Dustin Y; Todd, Michael D

2014-01-01

Structural health monitoring (SHM) systems provide real-time damage and performance information for civil, aerospace, and other high-capital or life-safety critical structures. Conventional data processing involves pre-processing and extraction of low-dimensional features from in situ time series measurements. The features are then input to a statistical pattern recognition algorithm to perform the relevant classification or regression task necessary to facilitate decisions by the SHM system. Traditional design of signal processing and feature extraction algorithms can be an expensive and time-consuming process requiring extensive system knowledge and domain expertise. Genetic programming, a heuristic program search method from evolutionary computation, was recently adapted by the authors to perform automated, data-driven design of signal processing and feature extraction algorithms for statistical pattern recognition applications. The proposed method, called Autofead, is particularly suitable to handle the challenges inherent in algorithm design for SHM problems where the manifestation of damage in structural response measurements is often unclear or unknown. Autofead mines a training database of response measurements to discover information-rich features specific to the problem at hand. This study provides experimental validation on three SHM applications including ultrasonic damage detection, bearing damage classification for rotating machinery, and vibration-based structural health monitoring. Performance comparisons with common feature choices for each problem area are provided demonstrating the versatility of Autofead to produce significant algorithm improvements on a wide range of problems. (paper)

Crucial Component Damage Detection, Monitoring and Mitigation, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This SBIR project delivers an on-board structural health-monitoring (SHM) system with embedded sensors that sense mechanical impedance deviations to flag incipient...

On the Value of Monitoring Information for the Structural Integrity and Risk Management

DEFF Research Database (Denmark)

Thöns, Sebastian

2018-01-01

facilitates the assessment of the value of information associated with SHM. The principal approach for the quantification of the value of SHM is formulated by modeling the fundamental decision of performing SHM or not in conjunction with their expected utilities. The expected utilities are calculated....... The calculation of the expected utilities necessitates a comprehensive and rigorous modeling, which is introduced close to the original formulations and for which analysis characteristics and simplifications are described and derived. The framework provides the basis for the optimization of the structural risk......This article introduces an approach and framework for the quantification of the value of structural health monitoring (SHM) in the context of the structural risk and integrity management for systems.The quantification of the value of SHM builds upon the Bayesian decision and utility theory, which...

Application of multi-scale (cross-) sample entropy for structural health monitoring

Science.gov (United States)

Lin, Tzu-Kang; Liang, Jui-Chang

2015-08-01

This study proposes an information-theoretic structural health monitoring (SHM) system based on multi-scale entropy (MSE) and multi-scale cross-sample entropy (MSCE). By measuring the ambient vibration signal from a structure, the damage condition can be rapidly evaluated via MSE analysis. The damage location can then be detected by analyzing the signals of different floors under the same damage condition via MSCE analysis. Moreover, a damage index is proposed to efficiently quantify the SHM process. Unlike some existing SHM methods, no experimental database or numerical model is required. Instead, a reference measurement of the current stage can initiate and launch the SHM system. A numerical simulation of a four-story steel structure is used to verify that the damage location and condition can be detected by the proposed SHM algorithm, and the location can be efficiently quantified by the damage index. A seven-story scaled-down benchmark structure is then employed for experimental verification. Based on the results, the damage condition can be correctly assessed, and average accuracy rates of 63.4 and 86.6% for the damage location can be achieved using the MSCE and damage index methods, respectively. As only the ambient vibration signal is required with a set of initial reference measurements, the proposed SHM system can be implemented practically with low cost.

Development of a PZT-based wireless digital monitor for composite impact monitoring

International Nuclear Information System (INIS)

Liu, Peipei; Yuan, Shenfang; Qiu, Lei

2012-01-01

One of the major concerns in the whole lifetime of composite materials in aircraft is their susceptibility to impact damage. And there has existed a need in recent years to develop an online structural health monitoring (SHM) system for impact monitoring. This paper proposes a new PZT-based wireless digital impact monitoring system development method aimed at giving a localized area for further inspection. Based on this method, a PZT-based wireless digital impact monitor (WDIM) with advantages of compactness, light weight, low power consumption and high efficiency is developed. Differently from conventional SHM systems, the complex analog circuits are removed and the whole process is achieved in a digital way by turning the output of the PZT sensor directly into a digital queue through a comparator. A simple but efficient sub-region location method is implemented in a field programmable gate array (FPGA) as the processing core of the WDIM to detect and record the impact events. In addition, wireless communication technology is used in the WDIM to transmit data and form a monitoring network. To illustrate the capability of the WDIM, a complete process dealing with an impact event is investigated and the stability of the WDIM is also evaluated in this paper. The WDIM shows its potential for real online applications in aircraft. (paper)

Structural health monitoring of wind turbine blades

Science.gov (United States)

Rumsey, Mark A.; Paquette, Joshua A.

2008-03-01

As electric utility wind turbines increase in size, and correspondingly, increase in initial capital investment cost, there is an increasing need to monitor the health of the structure. Acquiring an early indication of structural or mechanical problems allows operators to better plan for maintenance, possibly operate the machine in a de-rated condition rather than taking the unit off-line, or in the case of an emergency, shut the machine down to avoid further damage. This paper describes several promising structural health monitoring (SHM) techniques that were recently exercised during a fatigue test of a 9 meter glass-epoxy and carbon-epoxy wind turbine blade. The SHM systems were implemented by teams from NASA Kennedy Space Center, Purdue University and Virginia Tech. A commercial off-the-shelf acoustic emission (AE) NDT system gathered blade AE data throughout the test. At a fatigue load cycle rate around 1.2 Hertz, and after more than 4,000,000 fatigue cycles, the blade was diagnostically and visibly failing at the out-board blade spar-cap termination point at 4.5 meters. For safety reasons, the test was stopped just before the blade completely failed. This paper provides an overview of the SHM and NDT system setups and some current test results.

Vibration-based structural health monitoring of harbor caisson structure

Science.gov (United States)

Lee, So-Young; Lee, So-Ra; Kim, Jeong-Tae

2011-04-01

This study presents vibration-based structural health monitoring method in foundation-structure interface of harbor caisson structure. In order to achieve the objective, the following approaches are implemented. Firstly, vibration-based response analysis method is selected and structural health monitoring (SHM) technique is designed for harbor caisson structure. Secondly, the performance of designed SHM technique for harbor structure is examined by FE analysis. Finally, the applicability of designed SHM technique for harbor structure is evaluated by dynamic tests on a lab-scaled caisson structure.

Information processing for aerospace structural health monitoring

Science.gov (United States)

Lichtenwalner, Peter F.; White, Edward V.; Baumann, Erwin W.

1998-06-01

Structural health monitoring (SHM) technology provides a means to significantly reduce life cycle of aerospace vehicles by eliminating unnecessary inspections, minimizing inspection complexity, and providing accurate diagnostics and prognostics to support vehicle life extension. In order to accomplish this, a comprehensive SHM system will need to acquire data from a wide variety of diverse sensors including strain gages, accelerometers, acoustic emission sensors, crack growth gages, corrosion sensors, and piezoelectric transducers. Significant amounts of computer processing will then be required to convert this raw sensor data into meaningful information which indicates both the diagnostics of the current structural integrity as well as the prognostics necessary for planning and managing the future health of the structure in a cost effective manner. This paper provides a description of the key types of information processing technologies required in an effective SHM system. These include artificial intelligence techniques such as neural networks, expert systems, and fuzzy logic for nonlinear modeling, pattern recognition, and complex decision making; signal processing techniques such as Fourier and wavelet transforms for spectral analysis and feature extraction; statistical algorithms for optimal detection, estimation, prediction, and fusion; and a wide variety of other algorithms for data analysis and visualization. The intent of this paper is to provide an overview of the role of information processing for SHM, discuss various technologies which can contribute to accomplishing this role, and present some example applications of information processing for SHM implemented at the Boeing Company.

Virtual Environments for Visualizing Structural Health Monitoring Sensor Networks, Data, and Metadata.

Science.gov (United States)

Napolitano, Rebecca; Blyth, Anna; Glisic, Branko

2018-01-16

Visualization of sensor networks, data, and metadata is becoming one of the most pivotal aspects of the structural health monitoring (SHM) process. Without the ability to communicate efficiently and effectively between disparate groups working on a project, an SHM system can be underused, misunderstood, or even abandoned. For this reason, this work seeks to evaluate visualization techniques in the field, identify flaws in current practices, and devise a new method for visualizing and accessing SHM data and metadata in 3D. More precisely, the work presented here reflects a method and digital workflow for integrating SHM sensor networks, data, and metadata into a virtual reality environment by combining spherical imaging and informational modeling. Both intuitive and interactive, this method fosters communication on a project enabling diverse practitioners of SHM to efficiently consult and use the sensor networks, data, and metadata. The method is presented through its implementation on a case study, Streicker Bridge at Princeton University campus. To illustrate the efficiency of the new method, the time and data file size were compared to other potential methods used for visualizing and accessing SHM sensor networks, data, and metadata in 3D. Additionally, feedback from civil engineering students familiar with SHM is used for validation. Recommendations on how different groups working together on an SHM project can create SHM virtual environment and convey data to proper audiences, are also included.

Monitoring of Structures and Mechanical Systems Using Virtual Visual Sensors for Video Analysis: Fundamental Concept and Proof of Feasibility

Directory of Open Access Journals (Sweden)

Thomas Schumacher

2013-12-01

Full Text Available Structural health monitoring (SHM has become a viable tool to provide owners of structures and mechanical systems with quantitative and objective data for maintenance and repair. Traditionally, discrete contact sensors such as strain gages or accelerometers have been used for SHM. However, distributed remote sensors could be advantageous since they don’t require cabling and can cover an area rather than a limited number of discrete points. Along this line we propose a novel monitoring methodology based on video analysis. By employing commercially available digital cameras combined with efficient signal processing methods we can measure and compute the fundamental frequency of vibration of structural systems. The basic concept is that small changes in the intensity value of a monitored pixel with fixed coordinates caused by the vibration of structures can be captured by employing techniques such as the Fast Fourier Transform (FFT. In this paper we introduce the basic concept and mathematical theory of this proposed so-called virtual visual sensor (VVS, we present a set of initial laboratory experiments to demonstrate the accuracy of this approach, and provide a practical in-service monitoring example of an in-service bridge. Finally, we discuss further work to improve the current methodology.

Crack Propagation Analysis Using Acoustic Emission Sensors for Structural Health Monitoring Systems

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Horn, Walter; Steck, James

2013-01-01

Aerospace systems are expected to remain in service well beyond their designed life. Consequently, maintenance is an important issue. A novel method of implementing artificial neural networks and acoustic emission sensors to form a structural health monitoring (SHM) system for aerospace inspection routines was the focus of this research. Simple structural elements, consisting of flat aluminum plates of AL 2024-T3, were subjected to increasing static tensile loading. As the loading increased, designed cracks extended in length, releasing strain waves in the process. Strain wave signals, measured by acoustic emission sensors, were further analyzed in post-processing by artificial neural networks (ANN). Several experiments were performed to determine the severity and location of the crack extensions in the structure. ANNs were trained on a portion of the data acquired by the sensors and the ANNs were then validated with the remaining data. The combination of a system of acoustic emission sensors, and an ANN could determine crack extension accurately. The difference between predicted and actual crack extensions was determined to be between 0.004 in. and 0.015 in. with 95% confidence. These ANNs, coupled with acoustic emission sensors, showed promise for the creation of an SHM system for aerospace systems. PMID:24023536

Inspection of Piezoceramic Transducers Used for Structural Health Monitoring

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Inka Mueller

2017-01-01

Full Text Available The use of piezoelectric wafer active sensors (PWAS for structural health monitoring (SHM purposes is state of the art for acousto-ultrasonic-based methods. For system reliability, detailed information about the PWAS itself is necessary. This paper gives an overview on frequent PWAS faults and presents the effects of these faults on the wave propagation, used for active acousto-ultrasonics-based SHM. The analysis of the wave field is based on velocity measurements using a laser Doppler vibrometer (LDV. New and established methods of PWAS inspection are explained in detail, listing advantages and disadvantages. The electro-mechanical impedance spectrum as basis for these methods is discussed for different sensor faults. This way this contribution focuses on a detailed analysis of PWAS and the need of their inspection for an increased reliability of SHM systems.

Highly Reliable Structural Health Monitoring of Smart Composite Vanes for Jet Engine, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Intelligent Fiber Optic Systems and Auburn University propose a Fiber Bragg Grating (FBG) integrated Structural Health Monitoring (SHM) sensor system capable of...

Damage tolerance modeling and validation of a wireless sensory composite panel for a structural health monitoring system

Science.gov (United States)

Talagani, Mohamad R.; Abdi, Frank; Saravanos, Dimitris; Chrysohoidis, Nikos; Nikbin, Kamran; Ragalini, Rose; Rodov, Irena

2013-05-01

The paper proposes the diagnostic and prognostic modeling and test validation of a Wireless Integrated Strain Monitoring and Simulation System (WISMOS). The effort verifies a hardware and web based software tool that is able to evaluate and optimize sensorized aerospace composite structures for the purpose of Structural Health Monitoring (SHM). The tool is an extension of an existing suite of an SHM system, based on a diagnostic-prognostic system (DPS) methodology. The goal of the extended SHM-DPS is to apply multi-scale nonlinear physics-based Progressive Failure analyses to the "as-is" structural configuration to determine residual strength, remaining service life, and future inspection intervals and maintenance procedures. The DPS solution meets the JTI Green Regional Aircraft (GRA) goals towards low weight, durable and reliable commercial aircraft. It will take advantage of the currently developed methodologies within the European Clean sky JTI project WISMOS, with the capability to transmit, store and process strain data from a network of wireless sensors (e.g. strain gages, FBGA) and utilize a DPS-based methodology, based on multi scale progressive failure analysis (MS-PFA), to determine structural health and to advice with respect to condition based inspection and maintenance. As part of the validation of the Diagnostic and prognostic system, Carbon/Epoxy ASTM coupons were fabricated and tested to extract the mechanical properties. Subsequently two composite stiffened panels were manufactured, instrumented and tested under compressive loading: 1) an undamaged stiffened buckling panel; and 2) a damaged stiffened buckling panel including an initial diamond cut. Next numerical Finite element models of the two panels were developed and analyzed under test conditions using Multi-Scale Progressive Failure Analysis (an extension of FEM) to evaluate the damage/fracture evolution process, as well as the identification of contributing failure modes. The comparisons

Structural Health Monitoring with Fiber Bragg Grating and Piezo Arrays, Phase II

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National Aeronautics and Space Administration — IFOS and its research institute collaborator, Washington State University (WSU), have demonstrated feasibility of a structural health monitoring (SHM) system for...

A structural health monitoring fastener for tracking fatigue crack growth in bolted metallic joints

Science.gov (United States)

Rakow, Alexi Schroder

Fatigue cracks initiating at fastener hole locations in metallic components are among the most common form of airframe damage. The fastener hole site has been surveyed as the second leading initiation site for fatigue related accidents of fixed wing aircraft. Current methods for inspecting airframes for these cracks are manual, whereby inspectors rely on non-destructive inspection equipment or hand-held probes to scan over areas of a structure. Use of this equipment often demands disassembly of the vehicle to search appropriate hole locations for cracks, which elevates the complexity and cost of these maintenance inspections. Improved reliability, safety, and reduced cost of such maintenance can be realized by the permanent integration of sensors with a structure to detect this damage. Such an integrated system of sensors would form a structural health monitoring (SHM) system. In this study, an Additive, Interleaved, Multi-layer Electromagnetic (AIME) sensor was developed and integrated with the shank of a fastener to form a SHM Fastener, a new SHM technology targeted at detection of fastener hole cracks. The major advantages of the SHM Fastener are its installation, which does not require joint layer disassembly, its capability to detect inner layer cracks, and its capability to operate in a continuous autonomous mode. Two methods for fabricating the proposed SHM Fastener were studied. The first option consisted of a thin flexible printed circuit film that was bonded around a thin metallic sleeve placed around the fastener shank. The second option consisted of coating sensor materials directly to the shank of a part in an effort to increase the durability of the sensor under severe loading conditions. Both analytical and numerical models were developed to characterize the capability of the sensors and provide a design tool for the sensor layout. A diagnostic technique for crack growth monitoring was developed to complete the SHM system, which consists of the

Social and hygienic monitoring today: state and prospects in conjunction with the risk-based supervision

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N.V. Zaitseva

2016-12-01

Full Text Available It is shown in the article that since the establishment in 1992 and until now the social and health monitoring (SHM operates as a complex open system of extended collection and processing of heterogeneous data about the parameters of the environment, socio-economic indicators of living of the population of the country’s regions, medical and demographic characteristics of society as a whole and of individual population groups. As part of the SHM system Rospotrebnadzor annually performs hundreds of thousands of instrumental measurements of objects in the environment of the Russian Federation. These federal and regional information assets have tremendous analytical capacity and allow a knowledge-based processing of information in the "health-environment" system for a variety of management tasks of sanitary and epidemiological situation. Changing of the general paradigm of control and supervisory activities of Rospotrebnadzor and giving a fundamentally new status of control measures to researches and measurements of the system of social and hygienic monitoring without interaction with legal entities and individual entrepreneurs were important bases for further improvement of the SHM. The development of SHM in conjunction with the risk-based supervision model can significantly improve analytical capabilities, effectiveness and efficiency of each system. This development requires the adoption of a new edition of The statements of the SHM, the development of a scientific approach to the formation of "risk profiles" of objects of sanitary and epidemiological surveillance; the development of methodological approaches to the selection of points and formation of programs of instrumental studies of air, water and soil as the control activities in the areas of influence of economic entities. Of great current interest are the development and consolidation of regulatory requirements for the registration of the results of sampling and measurement in the

Probabilistic Structural Health Monitoring of the Orbiter Wing Leading Edge

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Yap, Keng C.; Macias, Jesus; Kaouk, Mohamed; Gafka, Tammy L.; Kerr, Justin H.

2011-01-01

A structural health monitoring (SHM) system can contribute to the risk management of a structure operating under hazardous conditions. An example is the Wing Leading Edge Impact Detection System (WLEIDS) that monitors the debris hazards to the Space Shuttle Orbiter s Reinforced Carbon-Carbon (RCC) panels. Since Return-to-Flight (RTF) after the Columbia accident, WLEIDS was developed and subsequently deployed on board the Orbiter to detect ascent and on-orbit debris impacts, so as to support the assessment of wing leading edge structural integrity prior to Orbiter re-entry. As SHM is inherently an inverse problem, the analyses involved, including those performed for WLEIDS, tend to be associated with significant uncertainty. The use of probabilistic approaches to handle the uncertainty has resulted in the successful implementation of many development and application milestones.

Dynamic Analysis with Fibre Optic Sensors for Structural Health Monitoring

National Research Council Canada - National Science Library

Paolozzi, Antonio; Gasbarri, Paolo

2006-01-01

Structural Health Monitoring (SHM) is a new frontier of non destructing testing. Often SHM is associated with fibre optic sensors whose signals can be used to identify the structure and consequently its damage...

New applications of a model of electromechanical impedance for SHM

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Pavelko, Vitalijs

2014-03-01

The paper focuses on the further development of the model of the electromechanical impedance (EMI) of the piezoceramics transducer (PZT) and its application for aircraft structural health monitoring (SHM). There was obtained an expression of the electromechanical impedance common to any dimension of models (1D, 2D, 3D), and directly independent from imposed constraints. Determination of the dynamic response of the system "host structure - PZT", which is crucial for the practical application supposes the use of modal analysis. This allows to get a general tool to determine EMI regardless of the specific features of a particular application. Earlier there was considered the technology of separate determination of the dynamic response for the PZT and the structural element". Here another version that involves the joint modal analysis of the entire system "host structure - PZT" is presented. As a result, the dynamic response is obtained in the form of modal decomposition of transducer mechanical strains. The use of models for the free and constrained transducer, analysis of the impact of the adhesive layer to the EMI is demonstrated. In all cases there was analyzed the influence of the dimension of the model (2D and 3D). The validity of the model is confirmed by experimental studies. Correlation between the fatigue crack length in a thin-walled Al plate and EMI of embedded PZT was simulated and compared with test result.

Reframing measurement for structural health monitoring: a full-field strategy for structural identification

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Dizaji, Mehrdad S.; Harris, Devin K.; Alipour, Mohamad; Ozbulut, Osman E.

2018-03-01

Structural health monitoring (SHM) describes a decision-making framework that is fundamentally guided by state change detection of structural systems. This framework typically relies on the use of continuous or semi-continuous monitoring of measured response to quantify this state change in structural system behavior, which is often related to the initiation of some form of damage. Measurement approaches used for traditional SHM are numerous, but most are limited to either describing localized or global phenomena, making it challenging to characterize operational structural systems which exhibit both. In addition to these limitations in sensing, SHM has also suffered from the inherent robustness inherent to most full-scale structural systems, making it challenging to identify local damage. These challenges highlight the opportunity for alternative strategies for SHM, strategies that are able to provide data suitable to translate into rich information. This paper describes preliminary results from a refined structural identification (St-ID) approach using fullfield measurements derived from high-speed 3D Digital Image Correlation (HSDIC) to characterize uncertain parameters (i.e. boundary and constitutive properties) of a laboratory scale structural component. The St-ID approach builds from prior work by supplementing full-field deflection and strain response with vibration response derived from HSDIC. Inclusion of the modal characteristics within a hybrid-genetic algorithm optimization scheme allowed for simultaneous integration of mechanical and modal response, thus enabling a more robust St-ID strategy than could be achieved with traditional sensing techniques. The use of full-field data is shown to provide a more comprehensive representation of the global and local behavior, which in turn increases the robustness of the St-Id framework. This work serves as the foundation for a new paradigm in SHM that emphasizes characterizing structural performance using a

Control of framed structures using intelligent monitoring networks

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Foti Dora

2017-01-01

Full Text Available The paper proposes the integration of structural monitoring with Building Management Systems for electricity and gas distributions. To assess the state of damage of existing buildings the technics of Structural Health Monitoring (SHM is adopted. SHM as well as to record the occurrence of sudden structural damage resulting from exceptional events (earthquakes, explosions, shocks and collisions with vehicles, etc., allows the monitoring of the progressive damage and structural performance under operating conditions through the extraction of the modal parameters of the structure. This approach requires time to process acquired data that, depending on the size of the building and the number of monitored points, varies from minutes to hours. In this paper, an intelligent system is proposed to immediately communicate during an earthquake the overrun of a certain ground shaking threshold so that gas delivery and selected power loads are interrupted, as suggested by current national regulations on structures. The use of low-cost and reduced size accelerometric sensors integrated with Energy Monitoring Systems is proposed in both highrisk earthquake centers and in all “strategic” buildings that must ensure their operation use immediately after the earthquake. The procedure for calibrating the horizontal and vertical acceleration threshold is also sketched.

Development and Application of a Structural Health Monitoring System Based on Wireless Smart Aggregates.

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Yan, Shi; Ma, Haoyan; Li, Peng; Song, Gangbing; Wu, Jianxin

2017-07-17

Structural health monitoring (SHM) systems can improve the safety and reliability of structures, reduce maintenance costs, and extend service life. Research on concrete SHMs using piezoelectric-based smart aggregates have reached great achievements. However, the newly developed techniques have not been widely applied in practical engineering, largely due to the wiring problems associated with large-scale structural health monitoring. The cumbersome wiring requires much material and labor work, and more importantly, the associated maintenance work is also very heavy. Targeting a practical large scale concrete crack detection (CCD) application, a smart aggregates-based wireless sensor network system is proposed for the CCD application. The developed CCD system uses Zigbee 802.15.4 protocols, and is able to perform dynamic stress monitoring, structural impact capturing, and internal crack detection. The system has been experimentally validated, and the experimental results demonstrated the effectiveness of the proposed system. This work provides important support for practical CCD applications using wireless smart aggregates.

Time-frequency Methods for Structural Health Monitoring

NARCIS (Netherlands)

Pyayt, A.L.; Kozionov, A.P.; Mokhov, I.I.; Lang, B.; Meijer, R.J.; Krzhizhanovskaya, V.V.; Sloot, P.M.A.

2014-01-01

Detection of early warning signals for the imminent failure of large and complex engineered structures is a daunting challenge with many open research questions. In this paper we report on novel ways to perform Structural Health Monitoring (SHM) of flood protection systems (levees, earthen dikes and

Time-frequency methods for structural health monitoring

NARCIS (Netherlands)

Pyayt, A.L.; Kozionov, A.P.; Mokhov, I.I.; Lang, B.; Meijer, R.J.; Krzhizhanovskaya, V.V.; Sloot, P.M.A.

2014-01-01

Detection of early warning signals for the imminent failure of large and complex engineered structures is a daunting challenge with many open research questions. In this paper we report on novel ways to perform Structural Health Monitoring (SHM) of flood protection systems (levees, earthen dikes and

Multidisciplinary health monitoring of a steel bridge deck structure

NARCIS (Netherlands)

Pahlavan, P.L.; Pijpers, R.J.M.; Paulissen, J.H.; Hakkesteegt, H.C.; Jansen, T.H.

2013-01-01

Fatigue cracks in orthotropic bridge decks are an important cause for the necessary renovation of existing bridges. Parallel utilization of various technologies based on different physical sensing principles can potentially maximize the efficiency of structural health monitoring (SHM) systems for

Synergistic combination of systems for structural health monitoring and earthquake early warning for structural health prognosis and diagnosis

Science.gov (United States)

Wu, Stephen; Beck, James L.

2012-04-01

Earthquake early warning (EEW) systems are currently operating nationwide in Japan and are in beta-testing in California. Such a system detects an earthquake initiation using online signals from a seismic sensor network and broadcasts a warning of the predicted location and magnitude a few seconds to a minute or so before an earthquake hits a site. Such a system can be used synergistically with installed structural health monitoring (SHM) systems to enhance pre-event prognosis and post-event diagnosis of structural health. For pre-event prognosis, the EEW system information can be used to make probabilistic predictions of the anticipated damage to a structure using seismic loss estimation methodologies from performance-based earthquake engineering. These predictions can support decision-making regarding the activation of appropriate mitigation systems, such as stopping traffic from entering a bridge that has a predicted high probability of damage. Since the time between warning and arrival of the strong shaking is very short, probabilistic predictions must be rapidly calculated and the decision making automated for the mitigation actions. For post-event diagnosis, the SHM sensor data can be used in Bayesian updating of the probabilistic damage predictions with the EEW predictions as a prior. Appropriate Bayesian methods for SHM have been published. In this paper, we use pre-trained surrogate models (or emulators) based on machine learning methods to make fast damage and loss predictions that are then used in a cost-benefit decision framework for activation of a mitigation measure. A simple illustrative example of an infrastructure application is presented.

Regionalization Study of Satellite based Hydrological Model (SHM) in Hydrologically Homogeneous River Basins of India

Science.gov (United States)

Kumari, Babita; Paul, Pranesh Kumar; Singh, Rajendra; Mishra, Ashok; Gupta, Praveen Kumar; Singh, Raghvendra P.

2017-04-01

A new semi-distributed conceptual hydrological model, namely Satellite based Hydrological Model (SHM), has been developed under 'PRACRITI-2' program of Space Application Centre (SAC), Ahmedabad for sustainable water resources management of India by using data from Indian Remote Sensing satellites. Entire India is divided into 5km x 5km grid cells and properties at the center of the cells are assumed to represent the property of the cells. SHM contains five modules namely surface water, forest, snow, groundwater and routing. Two empirical equations (SCS-CN and Hargreaves) and water balance method have been used in the surface water module; the forest module is based on the calculations of water balancing & dynamics of subsurface. 2-D Boussinesq equation is used for groundwater modelling which is solved using implicit finite-difference. The routing module follows a distributed routing approach which requires flow path and network with the key point of travel time estimation. The aim of this study is to evaluate the performance of SHM using regionalization technique which also checks the usefulness of a model in data scarce condition or for ungauged basins. However, homogeneity analysis is pre-requisite to regionalization. Similarity index (Φ) and hierarchical agglomerative cluster analysis are adopted to test the homogeneity in terms of physical attributes of three basins namely Brahmani (39,033 km km^2)), Baitarani (10,982 km km^2)) and Kangsabati (9,660 km km^2)) with respect to Subarnarekha (29,196 km km^2)) basin. The results of both homogeneity analysis show that Brahmani basin is the most homogeneous with respect to Subarnarekha river basin in terms of physical characteristics (land use land cover classes, soiltype and elevation). The calibration and validation of model parameters of Brahmani basin is in progress which are to be transferred into the SHM set up of Subarnarekha basin and results are to be compared with the results of calibrated and validated

An Experimental Study on Static and Dynamic Strain Sensitivity of Embeddable Smart Concrete Sensors Doped with Carbon Nanotubes for SHM of Large Structures

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Andrea Meoni

2018-03-01

Full Text Available The availability of new self-sensing cement-based strain sensors allows the development of dense sensor networks for Structural Health Monitoring (SHM of reinforced concrete structures. These sensors are fabricated by doping cement-matrix mterials with conductive fillers, such as Multi Walled Carbon Nanotubes (MWCNTs, and can be embedded into structural elements made of reinforced concrete prior to casting. The strain sensing principle is based on the multifunctional composites outputting a measurable change in their electrical properties when subjected to a deformation. Previous work by the authors was devoted to material fabrication, modeling and applications in SHM. In this paper, we investigate the behavior of several sensors fabricated with and without aggregates and with different MWCNT contents. The strain sensitivity of the sensors, in terms of fractional change in electrical resistivity for unit strain, as well as their linearity are investigated through experimental testing under both quasi-static and sine-sweep dynamic uni-axial compressive loadings. Moreover, the responses of the sensors when subjected to destructive compressive tests are evaluated. Overall, the presented results contribute to improving the scientific knowledge on the behavior of smart concrete sensors and to furthering their understanding for SHM applications.

An Experimental Study on Static and Dynamic Strain Sensitivity of Embeddable Smart Concrete Sensors Doped with Carbon Nanotubes for SHM of Large Structures.

Science.gov (United States)

Meoni, Andrea; D'Alessandro, Antonella; Downey, Austin; García-Macías, Enrique; Rallini, Marco; Materazzi, A Luigi; Torre, Luigi; Laflamme, Simon; Castro-Triguero, Rafael; Ubertini, Filippo

2018-03-09

The availability of new self-sensing cement-based strain sensors allows the development of dense sensor networks for Structural Health Monitoring (SHM) of reinforced concrete structures. These sensors are fabricated by doping cement-matrix mterials with conductive fillers, such as Multi Walled Carbon Nanotubes (MWCNTs), and can be embedded into structural elements made of reinforced concrete prior to casting. The strain sensing principle is based on the multifunctional composites outputting a measurable change in their electrical properties when subjected to a deformation. Previous work by the authors was devoted to material fabrication, modeling and applications in SHM. In this paper, we investigate the behavior of several sensors fabricated with and without aggregates and with different MWCNT contents. The strain sensitivity of the sensors, in terms of fractional change in electrical resistivity for unit strain, as well as their linearity are investigated through experimental testing under both quasi-static and sine-sweep dynamic uni-axial compressive loadings. Moreover, the responses of the sensors when subjected to destructive compressive tests are evaluated. Overall, the presented results contribute to improving the scientific knowledge on the behavior of smart concrete sensors and to furthering their understanding for SHM applications.

Structural Health Monitoring of Wind Turbine Blades: Acoustic Source Localization Using Wireless Sensor Networks

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Omar Mabrok Bouzid

2015-01-01

Full Text Available Structural health monitoring (SHM is important for reducing the maintenance and operation cost of safety-critical components and systems in offshore wind turbines. This paper proposes an in situ wireless SHM system based on an acoustic emission (AE technique. By using this technique a number of challenges are introduced due to high sampling rate requirements, limitations in the communication bandwidth, memory space, and power resources. To overcome these challenges, this paper focused on two elements: (1 the use of an in situ wireless SHM technique in conjunction with the utilization of low sampling rates; (2 localization of acoustic sources which could emulate impact damage or audible cracks caused by different objects, such as tools, bird strikes, or strong hail, all of which represent abrupt AE events and could affect the structural health of a monitored wind turbine blade. The localization process is performed using features extracted from aliased AE signals based on a developed constraint localization model. To validate the performance of these elements, the proposed system was tested by testing the localization of the emulated AE sources acquired in the field.

Acoustic emission detection with fiber optical sensors for dry cask storage health monitoring

Science.gov (United States)

Lin, Bin; Bao, Jingjing; Yu, Lingyu; Giurgiutiu, Victor

2016-04-01

The increasing number, size, and complexity of nuclear facilities deployed worldwide are increasing the need to maintain readiness and develop innovative sensing materials to monitor important to safety structures (ITS). In the past two decades, an extensive sensor technology development has been used for structural health monitoring (SHM). Technologies for the diagnosis and prognosis of a nuclear system, such as dry cask storage system (DCSS), can improve verification of the health of the structure that can eventually reduce the likelihood of inadvertently failure of a component. Fiber optical sensors have emerged as one of the major SHM technologies developed particularly for temperature and strain measurements. This paper presents the development of optical equipment that is suitable for ultrasonic guided wave detection for active SHM in the MHz range. An experimental study of using fiber Bragg grating (FBG) as acoustic emission (AE) sensors was performed on steel blocks. FBG have the advantage of being durable, lightweight, and easily embeddable into composite structures as well as being immune to electromagnetic interference and optically multiplexed. The temperature effect on the FBG sensors was also studied. A multi-channel FBG system was developed and compared with piezoelectric based AE system. The paper ends with conclusions and suggestions for further work.

Investigation of Wireless Sensor Networks for Structural Health Monitoring

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Ping Wang

2012-01-01

Full Text Available Wireless sensor networks (WSNs are one of the most able technologies in the structural health monitoring (SHM field. Through intelligent, self-organising means, the contents of this paper will test a variety of different objects and different working principles of sensor nodes connected into a network and integrated with data processing functions. In this paper the key issues of WSN applied in SHM are discussed, including the integration of different types of sensors with different operational modalities, sampling frequencies, issues of transmission bandwidth, real-time ability, and wireless transmitter frequency. Furthermore, the topology, data fusion, integration, energy saving, and self-powering nature of different systems will be investigated. In the FP7 project “Health Monitoring of Offshore Wind Farms,” the above issues are explored.

Packaging of structural health monitoring components

Science.gov (United States)

Kessler, Seth S.; Spearing, S. Mark; Shi, Yong; Dunn, Christopher T.

2004-07-01

Structural Health Monitoring (SHM) technologies have the potential to realize economic benefits in a broad range of commercial and defense markets. Previous research conducted by Metis Design and MIT has demonstrated the ability of Lamb waves methods to provide reliable information regarding the presence, location and type of damage in composite specimens. The present NSF funded program was aimed to study manufacturing, packaging and interface concepts for critical SHM components. The intention is to be able to cheaply manufacture robust actuating/sensing devices, and isolate them from harsh operating environments including natural, mechanical, or electrical extremes. Currently the issues related to SHM system durability have remained undressed. During the course of this research several sets of test devices were fabricated and packaged to protect the piezoelectric component assemblies for robust operation. These assemblies were then tested in hot and wet conditions, as well as in electrically noisy environments. Future work will aim to package the other supporting components such as the battery and wireless chip, as well as integrating all of these components together for operation. SHM technology will enable the reduction or complete elimination of scheduled inspections, and will allow condition-based maintenance for increased reliability and reduced overall life-cycle costs.

Wireless Smart Sensor Network System Using SmartBridge Sensor Nodes for Structural Health Monitoring of Existing Concrete Bridges

Science.gov (United States)

Gaviña, J. R.; Uy, F. A.; Carreon, J. D.

2017-06-01

There are over 8000 bridges in the Philippines today according to the Department of Public Works and Highways (DPWH). Currently, visual inspection is the most common practice in monitoring the structural integrity of bridges. However, visual inspections have proven to be insufficient in determining the actual health or condition of a bridge. Structural Health Monitoring (SHM) aims to give, in real-time, a diagnosis of the actual condition of the bridge. In this study, SmartBridge Sensor Nodes were installed on an existing concrete bridge with American Association of State Highway and Transportation Officials (AASHTO) Type IV Girders to gather vibration of the elements of the bridge. Also, standards on the effective installation of SmartBridge Sensor Nodes, such as location and orientation was determined. Acceleration readings from the sensor were then uploaded to a server, wherein they are monitored against certain thresholds, from which, the health of the bridge will be derived. Final output will be a portal or webpage wherein the information, health, and acceleration readings of the bridge will be available for viewing. With levels of access set for different types of users, the main users will have access to download data and reports. Data transmission and webpage access are available online, making the SHM system wireless.

Structural Health Monitoring for a Z-Type Special Vehicle

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Chaolin Yuan

2017-06-01

Full Text Available Nowadays there exist various kinds of special vehicles designed for some purposes, which are different from regular vehicles in overall dimension and design. In that case, accidents such as overturning will lead to large economical loss and casualties. There are still no technical specifications to follow to ensure the safe operation and driving of these special vehicles. Owing to the poor efficiency of regular maintenance, it is more feasible and effective to apply real-time monitoring during the operation and driving process. In this paper, the fiber Bragg grating (FBG sensors are used to monitor the safety of a z-type special vehicle. Based on the structural features and force distribution, a reasonable structural health monitoring (SHM scheme is presented. Comparing the monitoring results with the finite element simulation results guarantees the accuracy and reliability of the monitoring results. Large amounts of data are collected during the operation and driving progress to evaluate the structural safety condition and provide reference for SHM systems developed for other special vehicles.

The Model Of One-Type Aircraft Fleet Behaviour While Service And Advantages SHM V. NDT Implementation

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Lewitowicz Jerzy

2014-12-01

Full Text Available The paper defines the essence of durability characteristics of the designing structure of an airframe in terms of flight safety. Particular attention is drawn to one of the main factors influencing the durability characteristics of the airframe – diagnostics system for the health assessment of the airframe during the process of operation. The effectiveness of the use of integrated solutions to the structure of the airframe providing a continuous assessment of the technical condition is presented. Continuous diagnostics system integrated with the airframe, SHM, is classified as an intelligent solution. This paper presents a model of the behavior of one-type aircraft operating in the air operator’s fleet in terms of susceptibility to failure. Justified assumption in the description of this behavior, in the form of a “bathtub curve”. The analysis is supported by real data of failures. The benefits of using a continuous diagnostics system integrated with the airframe, SHM, is interpreted in relation to the classical approach with the use of non-destructive testing, NDT, for the three phases of the bathtub curve.

A Sensor Data Fusion System Based on k-Nearest Neighbor Pattern Classification for Structural Health Monitoring Applications

Directory of Open Access Journals (Sweden)

Jaime Vitola

2017-02-01

Full Text Available Civil and military structures are susceptible and vulnerable to damage due to the environmental and operational conditions. Therefore, the implementation of technology to provide robust solutions in damage identification (by using signals acquired directly from the structure is a requirement to reduce operational and maintenance costs. In this sense, the use of sensors permanently attached to the structures has demonstrated a great versatility and benefit since the inspection system can be automated. This automation is carried out with signal processing tasks with the aim of a pattern recognition analysis. This work presents the detailed description of a structural health monitoring (SHM system based on the use of a piezoelectric (PZT active system. The SHM system includes: (i the use of a piezoelectric sensor network to excite the structure and collect the measured dynamic response, in several actuation phases; (ii data organization; (iii advanced signal processing techniques to define the feature vectors; and finally; (iv the nearest neighbor algorithm as a machine learning approach to classify different kinds of damage. A description of the experimental setup, the experimental validation and a discussion of the results from two different structures are included and analyzed.

Value of information: A roadmap to quantifying the benefit of structural health monitoring

DEFF Research Database (Denmark)

Straub, D.; Chatzi, E.; Bismut, E.

2017-01-01

The concept of value of information (VoI) enables quantification of the benefits provided by structural health monitoring (SHM) systems – in principle. Its implementation is challenging, as it requires an explicit modelling of the structural system’s life cycle, in particular of the decisions...... that are taken based on the SHM information. In this paper, we approach the VoI analysis through an influence diagram (ID), which supports the modelling process. We provide a simple example for illustration and discuss challenges associated with real-life implementation....

A bio-inspired memory model for structural health monitoring

International Nuclear Information System (INIS)

Zheng, Wei; Zhu, Yong

2009-01-01

Long-term structural health monitoring (SHM) systems need intelligent management of the monitoring data. By analogy with the way the human brain processes memories, we present a bio-inspired memory model (BIMM) that does not require prior knowledge of the structure parameters. The model contains three time-domain areas: a sensory memory area, a short-term memory area and a long-term memory area. First, the initial parameters of the structural state are specified to establish safety criteria. Then the large amount of monitoring data that falls within the safety limits is filtered while the data outside the safety limits are captured instantly in the sensory memory area. Second, disturbance signals are distinguished from danger signals in the short-term memory area. Finally, the stable data of the structural balance state are preserved in the long-term memory area. A strategy for priority scheduling via fuzzy c-means for the proposed model is then introduced. An experiment on bridge tower deformation demonstrates that the proposed model can be applied for real-time acquisition, limited-space storage and intelligent mining of the monitoring data in a long-term SHM system

A bio-inspired memory model for structural health monitoring

Science.gov (United States)

Zheng, Wei; Zhu, Yong

2009-04-01

Long-term structural health monitoring (SHM) systems need intelligent management of the monitoring data. By analogy with the way the human brain processes memories, we present a bio-inspired memory model (BIMM) that does not require prior knowledge of the structure parameters. The model contains three time-domain areas: a sensory memory area, a short-term memory area and a long-term memory area. First, the initial parameters of the structural state are specified to establish safety criteria. Then the large amount of monitoring data that falls within the safety limits is filtered while the data outside the safety limits are captured instantly in the sensory memory area. Second, disturbance signals are distinguished from danger signals in the short-term memory area. Finally, the stable data of the structural balance state are preserved in the long-term memory area. A strategy for priority scheduling via fuzzy c-means for the proposed model is then introduced. An experiment on bridge tower deformation demonstrates that the proposed model can be applied for real-time acquisition, limited-space storage and intelligent mining of the monitoring data in a long-term SHM system.

A probabilistic approach for optimal sensor allocation in structural health monitoring

International Nuclear Information System (INIS)

Azarbayejani, M; Reda Taha, M M; El-Osery, A I; Choi, K K

2008-01-01

Recent advances in sensor technology promote using large sensor networks to efficiently and economically monitor, identify and quantify damage in structures. In structural health monitoring (SHM) systems, the effectiveness and reliability of the sensor network are crucial to determine the optimal number and locations of sensors in SHM systems. Here, we suggest a probabilistic approach for identifying the optimal number and locations of sensors for SHM. We demonstrate a methodology to establish the probability distribution function that identifies the optimal sensor locations such that damage detection is enhanced. The approach is based on using the weights of a neural network trained from simulations using a priori knowledge about damage locations and damage severities to generate a normalized probability distribution function for optimal sensor allocation. We also demonstrate that the optimal sensor network can be related to the highest probability of detection (POD). The redundancy of the proposed sensor network is examined using a 'leave one sensor out' analysis. A prestressed concrete bridge is selected as a case study to demonstrate the effectiveness of the proposed method. The results show that the proposed approach can provide a robust design for sensor networks that are more efficient than a uniform distribution of sensors on a structure

Development of a High-Sensitivity Wireless Accelerometer for Structural Health Monitoring.

Science.gov (United States)

Zhu, Li; Fu, Yuguang; Chow, Raymond; Spencer, Billie F; Park, Jong Woong; Mechitov, Kirill

2018-01-17

Structural health monitoring (SHM) is playing an increasingly important role in ensuring the safety of structures. A shift of SHM research away from traditional wired methods toward the use of wireless smart sensors (WSS) has been motivated by the attractive features of wireless smart sensor networks (WSSN). The progress achieved in Micro Electro-Mechanical System (MEMS) technologies and wireless data transmission, has extended the effectiveness and range of applicability of WSSNs. One of the most common sensors employed in SHM strategies is the accelerometer; however, most accelerometers in WSS nodes have inadequate resolution for measurement of the typical accelerations found in many SHM applications. In this study, a high-resolution and low-noise tri-axial digital MEMS accelerometer is incorporated in a next-generation WSS platform, the Xnode. In addition to meeting the acceleration sensing demands of large-scale civil infrastructure applications, this new WSS node provides powerful hardware and a robust software framework to enable edge computing that can deliver actionable information. Hardware and software integration challenges are presented, and the associate resolutions are discussed. The performance of the wireless accelerometer is demonstrated experimentally through comparison with high-sensitivity wired accelerometers. This new high-sensitivity wireless accelerometer will extend the use of WSSN to a broader class of SHM applications.

Development of a High-Sensitivity Wireless Accelerometer for Structural Health Monitoring

Science.gov (United States)

Zhu, Li; Fu, Yuguang; Chow, Raymond; Spencer, Billie F.; Park, Jong Woong; Mechitov, Kirill

2018-01-01

Structural health monitoring (SHM) is playing an increasingly important role in ensuring the safety of structures. A shift of SHM research away from traditional wired methods toward the use of wireless smart sensors (WSS) has been motivated by the attractive features of wireless smart sensor networks (WSSN). The progress achieved in Micro Electro-Mechanical System (MEMS) technologies and wireless data transmission, has extended the effectiveness and range of applicability of WSSNs. One of the most common sensors employed in SHM strategies is the accelerometer; however, most accelerometers in WSS nodes have inadequate resolution for measurement of the typical accelerations found in many SHM applications. In this study, a high-resolution and low-noise tri-axial digital MEMS accelerometer is incorporated in a next-generation WSS platform, the Xnode. In addition to meeting the acceleration sensing demands of large-scale civil infrastructure applications, this new WSS node provides powerful hardware and a robust software framework to enable edge computing that can deliver actionable information. Hardware and software integration challenges are presented, and the associate resolutions are discussed. The performance of the wireless accelerometer is demonstrated experimentally through comparison with high-sensitivity wired accelerometers. This new high-sensitivity wireless accelerometer will extend the use of WSSN to a broader class of SHM applications. PMID:29342102

Printing of microstructure strain sensor for structural health monitoring

Science.gov (United States)

Le, Minh Quyen; Ganet, Florent; Audigier, David; Capsal, Jean-Fabien; Cottinet, Pierre-Jean

2017-05-01

Recent advances in microelectronics and materials should allow the development of integrated sensors with transduction properties compatible with being printed directly onto a 3D substrate, especially metallic and polymer substrates. Inorganic and organic electronic materials in microstructured and nanostructured forms, intimately integrated in ink, offer particularly attractive characteristics, with realistic pathways to sophisticated embodiments. Here, we report on these strategies and demonstrate the potential of 3D-printed microelectronics based on a structural health monitoring (SHM) application for the precision weapon systems. We show that our printed sensors can be employed in non-invasive, high-fidelity and continuous strain monitoring of handguns, making it possible to implement printed sensors on a 3D substrate in either SHM or remote diagnostics. We propose routes to commercialization and novel device opportunities and highlight the remaining challenges for research.

Design of external sensors board based on Bluetooth interface of smart phones for structural health monitoring system

Science.gov (United States)

Yu, Yan; Zhou, Yaping; Zhao, Xuefeng; Li, Dongsheng; Ou, Jinping

2016-04-01

As an important part of new information technology, the Internet of Things(IoT) is based on intelligent perception, recognition technology, ubiquitous computing, ubiquitous network integration, and it is known as the third wave of the development of information industry in the world after the computer and the Internet. And Smart Phones are the general term for a class of mobile phones with a separate operating system and operational memory, in which the third-party service programs including software, games, navigation, et.al, can be installed. Smart Phones, with not only sensors but also actuators, are widely used in the IoT world. As the current hot issues in the engineering area, Structural health monitoring (SHM) is also facing new problems about design ideas in the IoT environment. The development of IoT, wireless sensor network and mobile communication technology, provides a good technical platform for SHM. Based on these facts, this paper introduces a kind of new idea for Structural Health Monitoring using Smart Phones Technique. The system is described in detail, and the external sensor board based on Bluetooth interface is designed, the test based on Smart Phones is finished to validate the implementation and feasibility. The research is preliminary and more tests need to be carried out before it can be of practical use.

Structural Health Monitoring with Fiber Bragg Grating and Piezo Arrays

Science.gov (United States)

Black, Richard J.; Faridian, Ferey; Moslehi, Behzad; Sotoudeh, Vahid

2012-01-01

Structural health monitoring (SHM) is one of the most important tools available for the maintenance, safety, and integrity of aerospace structural systems. Lightweight, electromagnetic-interference- immune, fiber-optic sensor-based SHM will play an increasing role in more secure air transportation systems. Manufacturers and maintenance personnel have pressing needs for significantly improving safety and reliability while providing for lower inspection and maintenance costs. Undetected or untreated damage may grow and lead to catastrophic structural failure. Damage can originate from the strain/stress history of the material, imperfections of domain boundaries in metals, delamination in multi-layer materials, or the impact of machine tools in the manufacturing process. Damage can likewise develop during service life from wear and tear, or under extraordinary circumstances such as with unusual forces, temperature cycling, or impact of flying objects. Monitoring and early detection are key to preventing a catastrophic failure of structures, especially when these are expected to perform near their limit conditions.

Structural health monitoring for ship structures

Energy Technology Data Exchange (ETDEWEB)

Farrar, Charles [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory; Angel, Marian [Los Alamos National Laboratory; Bement, Matthew [Los Alamos National Laboratory; Salvino, Liming [NSWC, CADEROCK

2009-01-01

Currently the Office of Naval Research is supporting the development of structural health monitoring (SHM) technology for U.S. Navy ship structures. This application is particularly challenging because of the physical size of these structures, the widely varying and often extreme operational and environmental conditions associated with these ships missions, lack of data from known damage conditions, limited sensing that was not designed specifically for SHM, and the management of the vast amounts of data that can be collected during a mission. This paper will first define a statistical pattern recognition paradigm for SHM by describing the four steps of (1) Operational Evaluation, (2) Data Acquisition, (3) Feature Extraction, and (4) Statistical Classification of Features as they apply to ship structures. Note that inherent in the last three steps of this process are additional tasks of data cleansing, compression, normalization and fusion. The presentation will discuss ship structure SHM challenges in the context of applying various SHM approaches to sea trials data measured on an aluminum multi-hull high-speed ship, the HSV-2 Swift. To conclude, the paper will discuss several outstanding issues that need to be addressed before SHM can make the transition from a research topic to actual field applications on ship structures and suggest approaches for addressing these issues.

Structural health monitoring for fatigue life prediction of orthotropic brdige decks

NARCIS (Netherlands)

Pijpers, R.J.M.; Pahlavan, P.L.; Paulissen, J.H.; Hakkesteegt, H.C.; Jansen, T.H.

2013-01-01

Infrastructure asset owners are more and more confronted with structures reaching the end of their structural life. Structural Health Monitoring (SHM) systems should provide up-to-date information about the actual condition, as well predict the structural life and required maintenance of the assets

Development of a Wireless Unified-Maintenance System for the Structural Health Monitoring of Civil Structures.

Science.gov (United States)

Heo, Gwanghee; Son, Byungjik; Kim, Chunggil; Jeon, Seunggon; Jeon, Joonryong

2018-05-09

A disaster preventive structural health monitoring (SHM) system needs to be equipped with the following abilities: First, it should be able to simultaneously measure diverse types of data (e.g., displacement, velocity, acceleration, strain, load, temperature, humidity, etc.) for accurate diagnosis. Second, it also requires standalone power supply to guarantee its immediate response in crisis (e.g., sudden interruption of normal AC power in disaster situations). Furthermore, it should be capable of prompt processing and realtime wireless communication of a huge amount of data. Therefore, this study is aimed at developing a wireless unified-maintenance system (WUMS) that would satisfy all the requirements for a disaster preventive SHM system of civil structures. The WUMS is designed to measure diverse types of structural responses in realtime based on wireless communication, allowing users to selectively use WiFi RF band and finally working in standalone mode by means of the field-programmable gate array (FPGA) technology. To verify its performance, the following tests were performed: (i) A test to see how far communication is possible in open field, (ii) a test on a shaker to see how accurate responses are, (iii) a modal test on a bridge to see how exactly characteristic real-time dynamic responses are of structures. The test results proved that the WUMS was able to secure stable communication far up to nearly 800 m away by acquiring wireless responses in realtime accurately, when compared to the displacement and acceleration responses which were acquired through wired communication. The analysis of dynamic characteristics also showed that the wireless acceleration responses in real-time represented satisfactorily the dynamic properties of structures. Therefore, the WUMS is proved valid as a SHM, and its outstanding performance is also proven.

Coupling Sensing Hardware with Data Interrogation Software for Structural Health Monitoring

Directory of Open Access Journals (Sweden)

Charles R. Farrar

2006-01-01

Full Text Available The process of implementing a damage detection strategy for aerospace, civil and mechanical engineering infrastructure is referred to as structural health monitoring (SHM. The authors' approach is to address the SHM problem in the context of a statistical pattern recognition paradigm. In this paradigm, the process can be broken down into four parts: (1 Operational Evaluation, (2 Data Acquisition and Cleansing, (3 Feature Extraction and Data Compression, and (4 Statistical Model Development for Feature Discrimination. These processes must be implemented through hardware or software and, in general, some combination of these two approaches will be used. This paper will discuss each portion of the SHM process with particular emphasis on the coupling of a general purpose data interrogation software package for structural health monitoring with a modular wireless sensing and processing platform. More specifically, this paper will address the need to take an integrated hardware/software approach to developing SHM solutions.

Internet of Things (IoT Platform for Structure Health Monitoring

Directory of Open Access Journals (Sweden)

Ahmed Abdelgawad

2017-01-01

Full Text Available Increase in the demand for reliable structural health information led to the development of Structural Health Monitoring (SHM. Prediction of upcoming accidents and estimation of useful life span of a structure are facilitated through SHM. While data sensing is the core of any SHM, tracking the data anytime anywhere is a prevailing challenge. With the advancement in information technology, the concept of Internet of Things (IoT has made it possible to integrate SHM with Internet to track data anytime anywhere. In this paper, a SHM platform embedded with IoT is proposed to detect the size and location of damage in structures. The proposed platform consists of a Wi-Fi module, a Raspberry Pi, an Analog to Digital Converter (ADC, a Digital to Analog Converter (DAC, a buffer, and piezoelectric (PZT sensors. The piezoelectric sensors are mounted as a pair in the structure. Data collected from the piezoelectric sensors will be used to detect the size and location of damage using a proposed mathematical model. Implemented on a Raspberry Pi, the proposed mathematical model will estimate the size and location of structural damage, if any, and upload the data to Internet. This data will be stored and can be checked remotely from any mobile device. The system has been validated using a real test bed in the lab.

Structural health monitoring an advanced signal processing perspective

CERN Document Server

Chen, Xuefeng; Mukhopadhyay, Subhas

2017-01-01

This book highlights the latest advances and trends in advanced signal processing (such as wavelet theory, time-frequency analysis, empirical mode decomposition, compressive sensing and sparse representation, and stochastic resonance) for structural health monitoring (SHM). Its primary focus is on the utilization of advanced signal processing techniques to help monitor the health status of critical structures and machines encountered in our daily lives: wind turbines, gas turbines, machine tools, etc. As such, it offers a key reference guide for researchers, graduate students, and industry professionals who work in the field of SHM.

Structural Nervous System, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — GTL's SNS technology aids in the operation of new or existing structural health monitoring (SHM) systems by integrating data and power pathways into the structure....

An autonomous structural health monitoring solution

Science.gov (United States)

Featherston, Carol A.; Holford, Karen M.; Pullin, Rhys; Lees, Jonathan; Eaton, Mark; Pearson, Matthew

2013-05-01

Combining advanced sensor technologies, with optimised data acquisition and diagnostic and prognostic capability, structural health monitoring (SHM) systems provide real-time assessment of the integrity of bridges, buildings, aircraft, wind turbines, oil pipelines and ships, leading to improved safety and reliability and reduced inspection and maintenance costs. The implementation of power harvesting, using energy scavenged from ambient sources such as thermal gradients and sources of vibration in conjunction with wireless transmission enables truly autonomous systems, reducing the need for batteries and associated maintenance in often inaccessible locations, alongside bulky and expensive wiring looms. The design and implementation of such a system however presents numerous challenges. A suitable energy source or multiple sources capable of meeting the power requirements of the system, over the entire monitoring period, in a location close to the sensor must be identified. Efficient power management techniques must be used to condition the power and deliver it, as required, to enable appropriate measurements to be taken. Energy storage may be necessary, to match a continuously changing supply and demand for a range of different monitoring states including sleep, record and transmit. An appropriate monitoring technique, capable of detecting, locating and characterising damage and delivering reliable information, whilst minimising power consumption, must be selected. Finally a wireless protocol capable of transmitting the levels of information generated at the rate needed in the required operating environment must be chosen. This paper considers solutions to some of these challenges, and in particular examines SHM in the context of the aircraft environment.

Identification of unusual events in multi-channel bridge monitoring data

Science.gov (United States)

Omenzetter, Piotr; Brownjohn, James Mark William; Moyo, Pilate

2004-03-01

Continuously operating instrumented structural health monitoring (SHM) systems are becoming a practical alternative to replace visual inspection for assessment of condition and soundness of civil infrastructure such as bridges. However, converting large amounts of data from an SHM system into usable information is a great challenge to which special signal processing techniques must be applied. This study is devoted to identification of abrupt, anomalous and potentially onerous events in the time histories of static, hourly sampled strains recorded by a multi-sensor SHM system installed in a major bridge structure and operating continuously for a long time. Such events may result, among other causes, from sudden settlement of foundation, ground movement, excessive traffic load or failure of post-tensioning cables. A method of outlier detection in multivariate data has been applied to the problem of finding and localising sudden events in the strain data. For sharp discrimination of abrupt strain changes from slowly varying ones wavelet transform has been used. The proposed method has been successfully tested using known events recorded during construction of the bridge, and later effectively used for detection of anomalous post-construction events.

Autonomous smart sensor network for full-scale structural health monitoring

Science.gov (United States)

Rice, Jennifer A.; Mechitov, Kirill A.; Spencer, B. F., Jr.; Agha, Gul A.

2010-04-01

The demands of aging infrastructure require effective methods for structural monitoring and maintenance. Wireless smart sensor networks offer the ability to enhance structural health monitoring (SHM) practices through the utilization of onboard computation to achieve distributed data management. Such an approach is scalable to the large number of sensor nodes required for high-fidelity modal analysis and damage detection. While smart sensor technology is not new, the number of full-scale SHM applications has been limited. This slow progress is due, in part, to the complex network management issues that arise when moving from a laboratory setting to a full-scale monitoring implementation. This paper presents flexible network management software that enables continuous and autonomous operation of wireless smart sensor networks for full-scale SHM applications. The software components combine sleep/wake cycling for enhanced power management with threshold detection for triggering network wide tasks, such as synchronized sensing or decentralized modal analysis, during periods of critical structural response.

An embedded stress sensor for concrete SHM based on amorphous ferromagnetic microwires.

Science.gov (United States)

Olivera, Jesús; González, Margarita; Fuente, José Vicente; Varga, Rastislav; Zhukov, Arkady; Anaya, José Javier

2014-10-24

A new smart concrete aggregate design as a candidate for applications in structural health monitoring (SHM) of critical elements in civil infrastructure is proposed. The cement-based stress/strain sensor was developed by utilizing the stress/strain sensing properties of a magnetic microwire embedded in cement-based composite (MMCC). This is a contact-less type sensor that measures variations of magnetic properties resulting from stress variations. Sensors made of these materials can be designed to satisfy the specific demand for an economic way to monitor concrete infrastructure health. For this purpose, we embedded a thin magnetic microwire in the core of a cement-based cylinder, which was inserted into the concrete specimen under study as an extra aggregate. The experimental results show that the embedded MMCC sensor is capable of measuring internal compressive stress around the range of 1-30 MPa. Two stress sensing properties of the embedded sensor under uniaxial compression were studied: the peak amplitude and peak position of magnetic switching field. The sensitivity values for the amplitude and position within the measured range were 5 mV/MPa and 2.5 µs/MPa, respectively.

An Embedded Stress Sensor for Concrete SHM Based on Amorphous Ferromagnetic Microwires

Directory of Open Access Journals (Sweden)

Jesús Olivera

2014-10-01

Full Text Available A new smart concrete aggregate design as a candidate for applications in structural health monitoring (SHM of critical elements in civil infrastructure is proposed. The cement-based stress/strain sensor was developed by utilizing the stress/strain sensing properties of a magnetic microwire embedded in cement-based composite (MMCC. This is a contact-less type sensor that measures variations of magnetic properties resulting from stress variations. Sensors made of these materials can be designed to satisfy the specific demand for an economic way to monitor concrete infrastructure health. For this purpose, we embedded a thin magnetic microwire in the core of a cement-based cylinder, which was inserted into the concrete specimen under study as an extra aggregate. The experimental results show that the embedded MMCC sensor is capable of measuring internal compressive stress around the range of 1–30 MPa. Two stress sensing properties of the embedded sensor under uniaxial compression were studied: the peak amplitude and peak position of magnetic switching field. The sensitivity values for the amplitude and position within the measured range were 5 mV/MPa and 2.5 µs/MPa, respectively.

Structural health monitoring system for bridges based on skin-like sensor

Science.gov (United States)

Loupos, Konstantinos; Damigos, Yannis; Amditis, Angelos; Gerhard, Reimund; Rychkov, Dmitry; Wirges, Werner; Schulze, Manuel; Lenas, Sotiris-Angelos; Chatziandreoglou, Christos; Malliou, Christina M.; Tsaoussidis, Vassilis; Brady, Ken; Frankenstein, Bernd

2017-09-01

Structural health monitoring activities are of primal importance for managing transport infrastructure, however most SHM methodologies are based on point-based sensors that have limitations in terms of their spatial positioning requirements, cost of development and measurement range. This paper describes the progress on the SENSKIN EC project whose objective is to develop a dielectric-elastomer and micro-electronics-based sensor, formed from a large highly extensible capacitance sensing membrane supported by advanced microelectronic circuitry, for monitoring transport infrastructure bridges. Such a sensor could provide spatial measurements of strain in excess of 10%. The actual sensor along with the data acquisition module, the communication module and power electronics are all integrated into a compact unit, the SENSKIN device, which is energy-efficient, requires simple signal processing and it is easy to install over various surface types. In terms of communication, SENSKIN devices interact with each other to form the SENSKIN system; a fully distributed and autonomous wireless sensor network that is able to self-monitor. SENSKIN system utilizes Delay-/Disruption-Tolerant Networking technologies to ensure that the strain measurements will be received by the base station even under extreme conditions where normal communications are disrupted. This paper describes the architecture of the SENSKIN system and the development and testing of the first SENSKIN prototype sensor, the data acquisition system, and the communication system.

ZnO Piezoelectric Nanowires for Use in a Self-Powered Structural Health Monitoring Device for Fiber-Reinforced Composites Uploading Attachment Instructions

Data.gov (United States)

National Aeronautics and Space Administration — The goal of this proposed research is to develop a new self-powered structural health monitoring (SHM) system for fiber-reinforced polymer (FRP) composites by using...

Investigation of the stochastic subspace identification method for on-line wind turbine tower monitoring

Science.gov (United States)

Dai, Kaoshan; Wang, Ying; Lu, Wensheng; Ren, Xiaosong; Huang, Zhenhua

2017-04-01

Structural health monitoring (SHM) of wind turbines has been applied in the wind energy industry to obtain their real-time vibration parameters and to ensure their optimum performance. For SHM, the accuracy of its results and the efficiency of its measurement methodology and data processing algorithm are the two major concerns. Selection of proper measurement parameters could improve such accuracy and efficiency. The Stochastic Subspace Identification (SSI) is a widely used data processing algorithm for SHM. This research discussed the accuracy and efficiency of SHM using SSI method to identify vibration parameters of on-line wind turbine towers. Proper measurement parameters, such as optimum measurement duration, are recommended.

Guided wave based structural health monitoring: A review

International Nuclear Information System (INIS)

Mitra, Mira; Gopalakrishnan, S

2016-01-01

The paper provides a state of the art review of guided wave based structural health monitoring (SHM). First, the fundamental concepts of guided wave propagation and its implementation for SHM is explained. Following sections present the different modeling schemes adopted, developments in the area of transducers for generation, and sensing of wave, signal processing and imaging technique, statistical and machine learning schemes for feature extraction. Next, a section is presented on the recent advancements in nonlinear guided wave for SHM. This is followed by section on Rayleigh and SH waves. Next is a section on real-life implementation of guided wave for industrial problems. The paper, though briefly talks about the early development for completeness, is primarily focussed on the recent progress made in the last decade. The paper ends by discussing and highlighting the future directions and open areas of research in guided wave based SHM. (topical review)

In situ health monitoring for bogie systems of CRH380 train on Beijing-Shanghai high-speed railway

Science.gov (United States)

Hong, Ming; Wang, Qiang; Su, Zhongqing; Cheng, Li

2014-04-01

Based on the authors' research efforts over the years, an in situ structural health monitoring (SHM) technique taking advantage of guided elastic waves has been developed and deployed via an online diagnosis system. The technique and the system were recently implemented on China's latest high-speed train (CRH380CL) operated on Beijing-Shanghai High-Speed Railway. The system incorporated modularized components including active sensor network, active wave generation, multi-channel data acquisition, signal processing, data fusion, and results presentation. The sensor network, inspired by a new concept—"decentralized standard sensing", was integrated into the bogie frames during the final assembly of CRH380CL, to generate and acquire bogie-guided ultrasonic waves, from which a wide array of signal features were extracted. Fusion of signal features through a diagnostic imaging algorithm led to a graphic illustration of the overall health state of the bogie in a real-time and intuitive manner. The in situ experimentation covered a variety of high-speed train operation events including startup, acceleration/deceleration, full-speed operation (300 km/h), emergency braking, track change, as well as full stop. Mock-up damage affixed to the bogie was identified quantitatively and visualized in images. This in situ testing has demonstrated the feasibility, effectiveness, sensitivity, and reliability of the developed SHM technique and the system towards real-world applications.

Structural health monitoring of bridge cables : An overview

OpenAIRE

DRISSI HABTI, Monssef; BETTI, Raimondo; YANEV, Bojidar

2009-01-01

Bridges are critical components of the civil infrastructure and are normally designed for a long life span. The life span of suspension bridges depends on the health of their cables, which, in turn, is a function of many factors. Therefore, continuous health monitoring (SHM) and regular condition assessment of cables is highly desirable. In this article, some SHM procedures based on direct, indirect non-destructive techniques NDT, and vibration theory are presented.

EPICS device support module as ATCA system manager for the ITER fast plant system controller

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Paulo F., E-mail: pricardofc@ipfn.ist.utl.pt [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico – Universidade Técnica de Lisboa, Lisboa (Portugal); Santos, Bruno; Gonçalves, Bruno; Carvalho, Bernardo B.; Sousa, Jorge; Rodrigues, A.P.; Batista, António J.N.; Correia, Miguel; Combo, Álvaro [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico – Universidade Técnica de Lisboa, Lisboa (Portugal); Correia, Carlos M.B.A. [Centro de Instrumentação, Departamento de Física, Universidade de Coimbra, Coimbra (Portugal); Varandas, Carlos A.F. [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico – Universidade Técnica de Lisboa, Lisboa (Portugal)

2013-10-15

Highlights: ► In Nuclear Fusion, demanding security and high-availability requirements call for redundancy to be available. ► ATCA based Nuclear Fusion Systems are composed by several electronic and mechanical component. ► Control and monitoring of ATCA electronic systems are recommended. ► ITER Fast Plant System Controller Project CODAC system prototype. ► EPICS device support module as External ATCA system manager solution. -- Abstract: This paper presents an Enhanced Physics and Industrial Control System (EPICS) device support module for the International Thermonuclear Experimental Reactor (ITER) Fast Plant System Controller (FPSC) project based in Advanced Telecommunications Computing Architecture (ATCA) specification. The developed EPICS device support module provides an External System Manager (ESM) solution for monitoring and control the ITER FPSC ATCA shelf system and data acquisition boards in order to take proper action and report problems to a control room operator or high level management unit in case of any system failure occurrence. EPICS device support module acts as a Channel Access (CA) server to report problems and publish ATCA system data information to the control room operator, high level management unit or other CA network clients such as Control System Studio Operator Interfaces (CSS OPIs), Best Ever Alarm System Toolkit (BEAST), Best Ever Archive Utility (BEAUTY) or other CA client applications. EPICS device support module communicates with the ATCA Shelf manager (ShM) using HTTP protocol to send and receive commands through POST method in order to get and set system and shelf components properties such as fan speeds measurements, temperatures readings, module status and ATCA boards acquisition and configuration parameters. All system properties, states, commands and parameters are available through the EPICS device support module CA server in EPICS Process Variables (PV) and signals format. ATCA ShM receives the HTTP protocol

Surface density mapping of natural tissue by a scanning haptic microscope (SHM).

Science.gov (United States)

Moriwaki, Takeshi; Oie, Tomonori; Takamizawa, Keiichi; Murayama, Yoshinobu; Fukuda, Toru; Omata, Sadao; Nakayama, Yasuhide

2013-02-01

To expand the performance capacity of the scanning haptic microscope (SHM) beyond surface mapping microscopy of elastic modulus or topography, surface density mapping of a natural tissue was performed by applying a measurement theory of SHM, in which a frequency change occurs upon contact of the sample surface with the SHM sensor - a microtactile sensor (MTS) that vibrates at a pre-determined constant oscillation frequency. This change was mainly stiffness-dependent at a low oscillation frequency and density-dependent at a high oscillation frequency. Two paragon examples with extremely different densities but similar macroscopic elastic moduli in the range of natural soft tissues were selected: one was agar hydrogels and the other silicon organogels with extremely low (less than 25 mg/cm(3)) and high densities (ca. 1300 mg/cm(3)), respectively. Measurements were performed in saline solution near the second-order resonance frequency, which led to the elastic modulus, and near the third-order resonance frequency. There was little difference in the frequency changes between the two resonance frequencies in agar gels. In contrast, in silicone gels, a large frequency change by MTS contact was observed near the third-order resonance frequency, indicating that the frequency change near the third-order resonance frequency reflected changes in both density and elastic modulus. Therefore, a density image of the canine aortic wall was subsequently obtained by subtracting the image observed near the second-order resonance frequency from that near the third-order resonance frequency. The elastin-rich region had a higher density than the collagen-rich region.

Reliability Assessment for PSC Box-Girder Bridges Based on SHM Strain Measurements

Directory of Open Access Journals (Sweden)

Chuang Chen

2017-01-01

Full Text Available A reliability assessment method for prestressed concrete (PSC continuous box-girder bridges based on structural health monitoring (SHM strain measurements was proposed. First, due to the fact that measured strain was compositive and the variation periods of its components were different, a series of limit state equations under normal use limit state were given. Then, a linear fitting method was used to determine the relationship between the ambient temperature and the measured strain, which was aimed at extracting the vehicle load effect and the temperature load effect from the measured strain. Finally, according to the equivalent normalization method, the load effects unsatisfying the normal distribution by probability density function fitting were transformed, and the daily failure probabilities of monitored positions were calculated for evaluating the safety state of the girder. The results show that (1 the top plate of the box girder is more sensitive than the bottom plate to the high temperature, (2 the daily and seasonal strain variations induced by uniform temperature reveal an inconsistent tendency to the seasonal variation for mid-span cross sections, and (3 the generalized extreme value distribution is recommended for temperature gradient stress and vehicle induced stress fitting for box-girder bridges.

Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge

Science.gov (United States)

Yap, Keng C.

2010-01-01

This viewgraph presentation reviews Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge. The Wing Leading Edge Impact Detection System (WLE IDS) and the Impact Analysis Process are also described to monitor WLE debris threats. The contents include: 1) Risk Management via SHM; 2) Hardware Overview; 3) Instrumentation; 4) Sensor Configuration; 5) Debris Hazard Monitoring; 6) Ascent Response Summary; 7) Response Signal; 8) Distribution of Flight Indications; 9) Probabilistic Risk Analysis (PRA); 10) Model Correlation; 11) Impact Tests; 12) Wing Leading Edge Modeling; 13) Ascent Debris PRA Results; and 14) MM/OD PRA Results.

A Brillouin smart FRP material and a strain data post processing software for structural health monitoring through laboratory testing and field application on a highway bridge

Science.gov (United States)

Bastianini, Filippo; Matta, Fabio; Galati, Nestore; Nanni, Antonio

2005-05-01

Strain and temperature sensing obtained through frequency shift evaluation of Brillouin scattered light is a technology that seems extremely promising for Structural Health Monitoring (SHM). Due to the intrinsic distributed sensing capability, Brillouin can measure the deformation of any individual segment of huge lengths of inexpensive single-mode fiber. In addition, Brillouin retains other typical advantages of Fiber Optic Sensors (FOS), such as harsh environment durability and interference rejection. Despite these advantages, the diffusion of Brillouin for SHM is constrained by different factors, such as the high equipment cost, the commercial unavailability of specific SHM oriented fiber products and even some prejudices on the required sensitivity performances. In the present work, a complete SHM pilot application was developed, installed and successfully operated during a diagnostic load test on the High Performance Steel (HPS) bridge A6358 located at the Lake of the Ozarks (Miller County, MO, USA). Four out of five girders were extensively instrumented with a "smart" Glass Fiber Reinforced Polymer (GFRP) tape having embedded fibers for strain sensing and thermal compensation. Data collected during a diagnostic load test were elaborated through a specific post-processing software, and the strain profiles retrieved were compared to traditional strain gauges and theoretical results based on the AASHTO LRFD Bridge Design Specifications for structural assessment purposes. The excellent results obtained confirm the effectiveness of Brillouin SHM systems for the monitoring of real applications.

On the value of structural health monitoring

DEFF Research Database (Denmark)

Faber, Michael Havbro; Thöns, Sebastian

2014-01-01

in the fields of SHM and the quantification of value of information as well as the identification of typical situations in structural engineering in which SHM has the potential to provide value beyond its costs. Subsequently, the theoretical framework which allows for the quantification of the value...... of information collected through SHM systems is developed and elaborated. It is shown how the value of information can be quantified to support the assessment and optimization of decisions on whether and how to implement SHM. To illustrate the use of the developed theoretical framework for evaluating the benefit...

Identification of unusual events in multichannel bridge monitoring data using wavelet transform and outlier analysis

Science.gov (United States)

Omenzetter, Piotr; Brownjohn, James M. W.; Moyo, Pilate

2003-08-01

Continuously operating instrumented structural health monitoring (SHM) systems are becoming a practical alternative to replace visual inspection for assessment of condition and soundness of civil infrastructure. However, converting large amount of data from an SHM system into usable information is a great challenge to which special signal processing techniques must be applied. This study is devoted to identification of abrupt, anomalous and potentially onerous events in the time histories of static, hourly sampled strains recorded by a multi-sensor SHM system installed in a major bridge structure in Singapore and operating continuously for a long time. Such events may result, among other causes, from sudden settlement of foundation, ground movement, excessive traffic load or failure of post-tensioning cables. A method of outlier detection in multivariate data has been applied to the problem of finding and localizing sudden events in the strain data. For sharp discrimination of abrupt strain changes from slowly varying ones wavelet transform has been used. The proposed method has been successfully tested using known events recorded during construction of the bridge, and later effectively used for detection of anomalous post-construction events.

Structural Health Monitoring Using Wireless Technologies: An Ambient Vibration Test on the Adolphe Bridge, Luxembourg City

Directory of Open Access Journals (Sweden)

Adrien Oth

2012-01-01

Full Text Available Major threats to bridges primarily consist of the aging of the structural elements, earthquake-induced shaking and standing waves generated by windstorms. The necessity of information on the state of health of structures in real-time, allowing for timely warnings in the case of damaging events, requires structural health monitoring (SHM systems that allow the risks of these threats to be mitigated. Here we present the results of a short-duration experiment carried out with low-cost wireless instruments for monitoring the vibration characteristics and dynamic properties of a strategic civil infrastructure, the Adolphe Bridge in Luxembourg City. The Adolphe Bridge is a masonry arch construction dating from 1903 and will undergo major renovation works in the upcoming years. Our experiment shows that a network of these wireless sensing units is well suited to monitor the vibration characteristics of such a historical arch bridge and hence represents a low-cost and efficient solution for SHM.

In-situ health monitoring of piezoelectric sensors using electromechanical impedance: A numerical perspective

Science.gov (United States)

Bilgunde, Prathamesh N.; Bond, Leonard J.

2018-04-01

Current work presents a numerical investigation to classify the in-situ health of the piezoelectric sensors deployed for structural health monitoring (SHM) of large civil, aircraft and automotive structures. The methodology proposed in this work attempts to model the in-homogeneities in the adhesive with which typically the sensor is bonded to the structure for SHM. It was found that weakening of the bond state causes reduction in the resonance frequency of the structure and eventually approaches the resonance characteristics of a piezoelectric material under traction-free boundary conditions. These changes in the resonance spectrum are further quantified using root mean square deviation-based damage index. Results demonstrate that the electromechanical impedance method can be used to monitor structural integrity of the sensor bonded to the host structure. This cost-effective method can potentially reduce misinterpretation of SHM data for critical infrastructures.

Structural health monitoring for DOT using magnetic shape memory alloy cables in concrete

Science.gov (United States)

Davis, Allen; Mirsayar, Mirmilad; Sheahan, Emery; Hartl, Darren

2018-03-01

Embedding shape memory alloy (SMA) wires in concrete components offers the potential to monitor their structural health via external magnetic field sensing. Currently, structural health monitoring (SHM) is dominated by acoustic emission and vibration-based methods. Thus, it is attractive to pursue alternative damage sensing techniques that may lower the cost or increase the accuracy of SHM. In this work, SHM via magnetic field detection applied to embedded magnetic shape memory alloy (MSMA) is demonstrated both experimentally and using computational models. A concrete beam containing iron-based MSMA wire is subjected to a 3-point bend test where structural damage is induced, thereby resulting in a localized phase change of the MSMA wire. Magnetic field lines passing through the embedded MSMA domain are altered by this phase change and can thus be used to detect damage within the structure. A good correlation is observed between the computational and experimental results. Additionally, the implementation of stranded MSMA cables in place of the MSMA wire is assessed through similar computational models. The combination of these computational models and their subsequent experimental validation provide sufficient support for the feasibility of SHM using magnetic field sensing via MSMA embedded components.

Exploitation of the Reverberant Propagation of Elastic Waves in Structures: Towards a Concept of Low-resource SHM Sensor Network

Science.gov (United States)

Moulin, Emmanuel; Benmeddour, Farouk; Achdjian, Hossep; Chehami, Lynda; Assaad, Jamal; de Rosny, Julien; Prada, Claire

Actual implementation of an efficient SHM system is necessarily hampered by the constraints of power-consumption and intrusive- ness (weight, size, in-service integration) of sensors. In the field of ultrasound-based SHM, conventional methods rely on relatively powerful acoustic sources synchronized with the sensors, and exploit only the first propagated (ballistic) wavepackets. The aim of this paper is to present possible techniques to exploit the whole complexity of reverberation signals, in order to extract the maxi- mum information from limited hardware, software, or power resources. A first aspect is the extraction of statistical properties of the codas of multiply-reflected signals, which can be used to estimate structural properties from a small number of sensors. In this technique, the required signal processing is relatively light and synchronization between the acquisition channels is not necessary. A second aspect is concerned with the possibility of using ambient acoustic sources, naturally present for example in transportation applications, instead of artificial power-consuming ultrasound sources.

A Wireless Sensor Network for Structural Health Monitoring: Performance and Experience

OpenAIRE

Paek, Jeongyeup; Chintalapudi, Krishna; Caffrey, John; Govindan, Ramesh; Masri, Sami

2005-01-01

While sensor network research has made significant strides in the past few years, the literature has relatively few examples of papers that have evaluated and validated a complete experimental system. In this paper we discuss our deployment experiences and evaluate the performance of a multi-hop wireless data acquisition system (called Wisden) for structural health monitoring (SHM) on a large seismic test structure used by civil engineers. Our experiments indicate that, with the latest sensor...

Distributed Piezoelectric Sensor System for Damage Identification in Structures Subjected to Temperature Changes

Directory of Open Access Journals (Sweden)

Jaime Vitola

2017-05-01

Full Text Available Structural health monitoring (SHM is a very important area in a wide spectrum of fields and engineering applications. With an SHM system, it is possible to reduce the number of non-necessary inspection tasks, the associated risk and the maintenance cost in a wide range of structures during their lifetime. One of the problems in the detection and classification of damage are the constant changes in the operational and environmental conditions. Small changes of these conditions can be considered by the SHM system as damage even though the structure is healthy. Several applications for monitoring of structures have been developed and reported in the literature, and some of them include temperature compensation techniques. In real applications, however, digital processing technologies have proven their value by: (i offering a very interesting way to acquire information from the structures under test; (ii applying methodologies to provide a robust analysis; and (iii performing a damage identification with a practical useful accuracy. This work shows the implementation of an SHM system based on the use of piezoelectric (PZT sensors for inspecting a structure subjected to temperature changes. The methodology includes the use of multivariate analysis, sensor data fusion and machine learning approaches. The methodology is tested and evaluated with aluminum and composite structures that are subjected to temperature variations. Results show that damage can be detected and classified in all of the cases in spite of the temperature changes.

Distributed Piezoelectric Sensor System for Damage Identification in Structures Subjected to Temperature Changes.

Science.gov (United States)

Vitola, Jaime; Pozo, Francesc; Tibaduiza, Diego A; Anaya, Maribel

2017-05-31

Structural health monitoring (SHM) is a very important area in a wide spectrum of fields and engineering applications. With an SHM system, it is possible to reduce the number of non-necessary inspection tasks, the associated risk and the maintenance cost in a wide range of structures during their lifetime. One of the problems in the detection and classification of damage are the constant changes in the operational and environmental conditions. Small changes of these conditions can be considered by the SHM system as damage even though the structure is healthy. Several applications for monitoring of structures have been developed and reported in the literature, and some of them include temperature compensation techniques. In real applications, however, digital processing technologies have proven their value by: (i) offering a very interesting way to acquire information from the structures under test; (ii) applying methodologies to provide a robust analysis; and (iii) performing a damage identification with a practical useful accuracy. This work shows the implementation of an SHM system based on the use of piezoelectric (PZT) sensors for inspecting a structure subjected to temperature changes. The methodology includes the use of multivariate analysis, sensor data fusion and machine learning approaches. The methodology is tested and evaluated with aluminum and composite structures that are subjected to temperature variations. Results show that damage can be detected and classified in all of the cases in spite of the temperature changes.

FOREWORD: Structural Health Monitoring and Intelligent Infrastructure

Science.gov (United States)

Wu, Zhishen; Fujino, Yozo

2005-06-01

This special issue collects together 19 papers that were originally presented at the First International Conference on Structural Health Monitoring and Intelligent Infrastructure (SHMII-1'2003), held in Tokyo, Japan, on 13-15 November 2003. This conference was organized by the Japan Society of Civil Engineers (JSCE) with partial financial support from the Japan Society for the Promotion of Science (JSPS) and the Ministry of Education, Culture, Sport, Science and Technology, Japan. Many related organizations supported the conference. A total of 16 keynote papers including six state-of-the-art reports from different counties, six invited papers and 154 contributed papers were presented at the conference. The conference was attended by a diverse group of about 300 people from a variety of disciplines in academia, industry and government from all over the world. Structural health monitoring (SHM) and intelligent materials, structures and systems have been the subject of intense research and development in the last two decades and, in recent years, an increasing range of applications in infrastructure have been discovered both for existing structures and for new constructions. SHMII-1'2003 addressed progress in the development of building, transportation, marine, underground and energy-generating structures, and other civilian infrastructures that are periodically, continuously and/or actively monitored where there is a need to optimize their performance. In order to focus the current needs on SHM and intelligent technologies, the conference theme was set as 'Structures/Infrastructures Sustainability'. We are pleased to have the privilege to edit this special issue on SHM and intelligent infrastructure based on SHMII-1'2003. We invited some of the presenters to submit a revised/extended version of their paper that was included in the SHMII-1'2003 proceedings for possible publication in the special issue. Each paper included in this special issue was edited with the same

Development and validation of a strain-based Structural Health Monitoring system

Science.gov (United States)

Katsikeros, Ch. E.; Labeas, G. N.

2009-02-01

An innovative Structural Health Monitoring (SHM) methodology, based on structural strain measurements, which are processed by a back-propagation feed-forward Artificial Neural Network (ANN), is proposed. The demonstration of the SHM methodology and the identification of its capabilities and drawbacks are performed by applying the method in the prediction of fatigue damage states of a typical aircraft cracked lap-joint structure. An ANN of suitable architecture is developed and trained by numerically generated strain data sets, which have been preprocessed by Fast Fourier Transformation (FFT) for the extraction of the Fourier Descriptors (FDs). The Finite Element (FE) substructuring technique is implemented in the stress and strain analysis of the lap-joint structure, due to its efficiency in the calculation of the numerous strain data, which are necessary for the ANN training. The trained network is successfully validated, as it is proven capable to accurately predict crack positions and lengths of a lap-joint structure, which is damaged by fatigue cracks of unknown location and extent. The proposed methodology is applicable to the identification of more complex types of damage or to other critical structural locations, as its basic concept is generic.

Sensor agent robot with servo-accelerometer for structural health monitoring

Science.gov (United States)

Lee, Nobukazu; Mita, Akira

2012-04-01

SHM systems are becoming feasible with the growth of computer and sensor technologies during the last decade. However, high cost prevents SHM to become common in general homes. The reason of this high cost is partially due to many accelerometers. In this research, we propose a moving sensor agent robot with accelerometers and a laser range finder (LRF). If this robot can properly measure accurate acceleration data, the cost of SHM would be cut down and resulting in the spread of SHM systems. Our goal is to develop a platform for SHM using the sensor agent robot. We designed the prototype robot to correctly detect the floor vibrations and acquire the micro tremor information. When the sensor agent robot is set in the mode of acquiring the data, the dynamics of the robot should be tuned not to be affected by its flexibility. To achieve this purpose the robot frame was modified to move down to the ground and to provide enough rigidity to obtain good data. In addition to this mechanism, we tested an algorithm to correctly know the location of the robot and the map of the floor to be used in the SHM system using the LRF and Simultaneously Localization and Mapping (SLAM).

Development of an embedded thin-film strain-gauge-based SHM network into 3D-woven composite structure for wind turbine blades

Science.gov (United States)

Zhao, Dongning; Rasool, Shafqat; Forde, Micheal; Weafer, Bryan; Archer, Edward; McIlhagger, Alistair; McLaughlin, James

2017-04-01

Recently, there has been increasing demand in developing low-cost, effective structure health monitoring system to be embedded into 3D-woven composite wind turbine blades to determine structural integrity and presence of defects. With measuring the strain and temperature inside composites at both in-situ blade resin curing and in-service stages, we are developing a novel scheme to embed a resistive-strain-based thin-metal-film sensory into the blade spar-cap that is made of composite laminates to determine structural integrity and presence of defects. Thus, with fiberglass, epoxy, and a thinmetal- film sensing element, a three-part, low-cost, smart composite laminate is developed. Embedded strain sensory inside composite laminate prototype survived after laminate curing process. The internal strain reading from embedded strain sensor under three-point-bending test standard is comparable. It proves that our proposed method will provide another SHM alternative to reduce sensing costs during the renewable green energy generation.

Structural health monitoring (vibration) as a tool for identifying structural alterations of the lumbar spine: a twin control study.

Science.gov (United States)

Kawchuk, Gregory N; Hartvigsen, Jan; Edgecombe, Tiffany; Prasad, Narasimha; van Dieen, Jaap H

2016-03-11

Structural health monitoring (SHM) is an engineering technique used to identify mechanical abnormalities not readily apparent through other means. Recently, SHM has been adapted for use in biological systems, but its invasive nature limits its clinical application. As such, the purpose of this project was to determine if a non-invasive form of SHM could identify structural alterations in the spines of living human subjects. Lumbar spines of 10 twin pairs were visualized by magnetic resonance imaging then assessed by a blinded radiologist to determine whether twin pairs were structurally concordant or discordant. Vibration was then applied to each subject's spine and the resulting response recorded from sensors overlying lumbar spinous processes. The peak frequency, area under the curve and the root mean square were computed from the frequency response function of each sensor. Statistical analysis demonstrated that in twins whose structural appearance was discordant, peak frequency was significantly different between twin pairs while in concordant twins, no outcomes were significantly different. From these results, we conclude that structural changes within the spine can alter its vibration response. As such, further investigation of SHM to identify spinal abnormalities in larger human populations is warranted.

A real-time remote sensing and data acquisition system for a nuclear power plant

International Nuclear Information System (INIS)

Kim, Ki Ho; Hieu, Bui Van; Beak, Seung Hyun; Choi, Seung Hwan; Son, Tae Ha; Kim, Jung Kuk; Han, Seung Chul

2011-01-01

A Structure Health Monitoring (SHM) system needs a real-time remote data acquisition system to monitor the status of a structure from anywhere via Internet access. In this paper, we present a data acquisition system that monitors up to 40 Fiber Bragg Grating Sensors remotely in real-time. Using a TCP/IP protocol, users can access information gathered by the sensors from anywhere. An experiment in laboratory conditions has been done to prove the feasibility of our proposed system, which is built in special-purpose monitoring system

Towards "Zero" False Positive in Structural Health Monitoring

National Research Council Canada - National Science Library

Chiu, Wing K; Chang, F. K; Tian, Daniel T

2007-01-01

Structural Health Monitoring (SHM) is one aspect of a revolution based on the use of Smart Materials and Structures technologies that have the potential to provide major gains in structural performance and cost-efficient life management...

Guaranteeing robustness of structural condition monitoring to environmental variability

Science.gov (United States)

Van Buren, Kendra; Reilly, Jack; Neal, Kyle; Edwards, Harry; Hemez, François

2017-01-01

Advances in sensor deployment and computational modeling have allowed significant strides to be recently made in the field of Structural Health Monitoring (SHM). One widely used SHM strategy is to perform a vibration analysis where a model of the structure's pristine (undamaged) condition is compared with vibration response data collected from the physical structure. Discrepancies between model predictions and monitoring data can be interpreted as structural damage. Unfortunately, multiple sources of uncertainty must also be considered in the analysis, including environmental variability, unknown model functional forms, and unknown values of model parameters. Not accounting for these sources of uncertainty can lead to false-positives or false-negatives in the structural condition assessment. To manage the uncertainty, we propose a robust SHM methodology that combines three technologies. A time series algorithm is trained using "baseline" data to predict the vibration response, compare predictions to actual measurements collected on a potentially damaged structure, and calculate a user-defined damage indicator. The second technology handles the uncertainty present in the problem. An analysis of robustness is performed to propagate this uncertainty through the time series algorithm and obtain the corresponding bounds of variation of the damage indicator. The uncertainty description and robustness analysis are both inspired by the theory of info-gap decision-making. Lastly, an appropriate "size" of the uncertainty space is determined through physical experiments performed in laboratory conditions. Our hypothesis is that examining how the uncertainty space changes throughout time might lead to superior diagnostics of structural damage as compared to only monitoring the damage indicator. This methodology is applied to a portal frame structure to assess if the strategy holds promise for robust SHM. (Publication approved for unlimited, public release on October-28

A self-synchronizing and low-cost structural health monitoring scheme based on zero crossing detection

International Nuclear Information System (INIS)

Guyomar, Daniel; Lallart, Mickaël; Li, Kaixiang; Gauthier, Jean-Yves; Monnier, Thomas

2010-01-01

Owing to their high specific strength and stiffness, composite materials are increasingly being used in aeronautics and astronautics, but such materials are vulnerable to impact damage and delamination. Structural health monitoring (SHM) techniques have been developed for detecting such defects in recent years. In situ, self-powered and low-cost SHM systems are a developmental tendency of this technique. This paper introduces the principles of a low-cost and self-synchronizing scheme for SHM. Based on the Lamb wave interactions with the structure, the proposed technique relies on detecting zero crossing time instants in order to derive an estimation of the structural state. It is shown that such a method provides a very simple and low-cost way to assess the structural integrity while being computationally efficient. Experimental investigations carried out on a composite plate with an increasing penetration hold validating the proposed technique show its effectiveness for detecting the damage. The proposed approach has also been applied on an aircraft outboard flap to detect the impact damage. The robustness is discussed versus time-shift and magnitude jitter assumptions by using the plate case. The temperature effect is also considered by defining a coefficient array in order to compensate for the material property changes. Finally, an embedded implementation of such a SHM technique is presented by using the proposed damage index

Flexible High Energy-Conversion Sensing Materials for Structural Health Monitoring, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The applicant is developing flexible highly-efficient piezoelectric materials for use in structural health monitoring (SHM) as contemplated in the solicitation...

Phase Space Dissimilarity Measures for Structural Health Monitoring

Energy Technology Data Exchange (ETDEWEB)

Bubacz, Jacob A [ORNL; Chmielewski, Hana T [ORNL; Pape, Alexander E [ORNL; Depersio, Andrew J [ORNL; Hively, Lee M [ORNL; Abercrombie, Robert K [ORNL; Boone, Shane [ORNL

2011-11-01

A novel method for structural health monitoring (SHM), known as the Phase Space Dissimilarity Measures (PSDM) approach, is proposed and developed. The patented PSDM approach has already been developed and demonstrated for a variety of equipment and biomedical applications. Here, we investigate SHM of bridges via analysis of time serial accelerometer measurements. This work has four aspects. The first is algorithm scalability, which was found to scale linearly from one processing core to four cores. Second, the same data are analyzed to determine how the use of the PSDM approach affects sensor placement. We found that a relatively low-density placement sufficiently captures the dynamics of the structure. Third, the same data are analyzed by unique combinations of accelerometer axes (vertical, longitudinal, and lateral with respect to the bridge) to determine how the choice of axes affects the analysis. The vertical axis is found to provide satisfactory SHM data. Fourth, statistical methods were investigated to validate the PSDM approach for this application, yielding statistically significant results.

The Feasibility of Structural Health Monitoring Using the Fundamental Shear Horizontal Guided Wave in a Thin Aluminum Plate

Directory of Open Access Journals (Sweden)

Jorge Franklin Mansur Rodrigues Filho

2017-05-01

Full Text Available Structural health monitoring (SHM is emerging as an essential tool for constant monitoring of safety-critical engineering components. Ultrasonic guided waves stand out because of their ability to propagate over long distances and because they can offer good estimates of location, severity, and type of damage. The unique properties of the fundamental shear horizontal guided wave (SH0 mode have recently generated great interest among the SHM community. The aim of this paper is to demonstrate the feasibility of omnidirectional SH0 SHM in a thin aluminum plate using a three-transducer sparse array. Descriptions of the transducer, the finite element model, and the imaging algorithm are presented. The image localization maps show a good agreement between the simulations and experimental results. The SH0 SHM method proposed in this paper is shown to have a high resolution and to be able to locate defects within 5% of the true location. The short input signal as well the non-dispersive nature of SH0 leads to high resolution in the reconstructed images. The defect diameter estimated using the full width at half maximum was 10 mm or twice the size of the true diameter.

Vibration based monitoring of stay cable force using wireless piezoelectric based strain sensor nodes

International Nuclear Information System (INIS)

Nguyen, Khac Duy; Kim, Jeong Tae

2012-01-01

This study presents a method to monitor cable force using wireless sensor nodes and piezoelectric sensors. The following approaches are carried out to achieve the objective. Firstly, the principle of piezoelectric materials (e.g., PZT) as strain sensors is reviewed. A cable force estimation method using dynamic features of cables measured by piezoelectric materials is presented. Secondly, the design of an automated cable force monitoring system using the data acquisition sensor node Imote2/SHM DAQ is described. The sensor node is originally developed by University of Illinois at Urbana champaign and is adopted in this study to monitor strain induced voltage from PZT sensors. The advantages of the system are cheap, and eligible for wireless communication and automated operation. Finally, the feasibility of the proposed monitoring system is evaluated on a lab scaled cable

In situ monitoring of mutagenicity of air pollutants in São Paulo City using Tradescantia-SHM bioassay

Directory of Open Access Journals (Sweden)

Ferreira Maria Izildinha

2003-01-01

Full Text Available The Tradescantia stamen hair mutation assay (Trad-SHM was employed for assessing the environmental mutagenesis in two areas of São Paulo City. The study sites were defined as follows: 1 Celso Garcia Avenue, an industrial area on the outskirts of the urban center (Belém neighborhood, with an average daily traffic volume of 8,750 vehicles; 2 Doutor Arnaldo Avenue, in downtown area (Pinheiros neighborhood, with a mostly residential and business offices occupation, with an average daily traffic volume of 46,125 vehicles. The negative control (background site is located in the city of Jaguariúna, 138 km from São Paulo, in an area of low atmospheric pollution. The mutation frequency observed for Belém was similar to the background for clone 4430, whereas plants exposed in Pinheiros showed significant increases in mutation rate. Positive correlation was observed between mutation frequency and the levels of particulate matter in the atmosphere. This indicated a relationship between mutation frequency and the amount of atmospheric pollution present at the exposure sites in São Paulo City, with special reference to vehicular emissions.

Simulation tools for guided wave based structural health monitoring

Science.gov (United States)

Mesnil, Olivier; Imperiale, Alexandre; Demaldent, Edouard; Baronian, Vahan; Chapuis, Bastien

2018-04-01

Structural Health Monitoring (SHM) is a thematic derived from Non Destructive Evaluation (NDE) based on the integration of sensors onto or into a structure in order to monitor its health without disturbing its regular operating cycle. Guided wave based SHM relies on the propagation of guided waves in plate-like or extruded structures. Using piezoelectric transducers to generate and receive guided waves is one of the most widely accepted paradigms due to the low cost and low weight of those sensors. A wide range of techniques for flaw detection based on the aforementioned setup is available in the literature but very few of these techniques have found industrial applications yet. A major difficulty comes from the sensitivity of guided waves to a substantial number of parameters such as the temperature or geometrical singularities, making guided wave measurement difficult to analyze. In order to apply guided wave based SHM techniques to a wider spectrum of applications and to transfer those techniques to the industry, the CEA LIST develops novel numerical methods. These methods facilitate the evaluation of the robustness of SHM techniques for multiple applicative cases and ease the analysis of the influence of various parameters, such as sensors positioning or environmental conditions. The first numerical tool is the guided wave module integrated to the commercial software CIVA, relying on a hybrid modal-finite element formulation to compute the guided wave response of perturbations (cavities, flaws…) in extruded structures of arbitrary cross section such as rails or pipes. The second numerical tool is based on the spectral element method [2] and simulates guided waves in both isotropic (metals) and orthotropic (composites) plate like-structures. This tool is designed to match the widely accepted sparse piezoelectric transducer array SHM configuration in which each embedded sensor acts as both emitter and receiver of guided waves. This tool is under development and

Sensor distributions for structural monitoring

DEFF Research Database (Denmark)

Ulriksen, Martin Dalgaard; Bernal, Dionisio

2017-01-01

Deciding on the spatial distribution of output sensors for vibration-based structural health monitoring (SHM) is a task that has been, and still is, studied extensively. Yet, when referring to the conventional damage characterization hierarchy, composed of detection, localization, and quantificat......Deciding on the spatial distribution of output sensors for vibration-based structural health monitoring (SHM) is a task that has been, and still is, studied extensively. Yet, when referring to the conventional damage characterization hierarchy, composed of detection, localization......, and quantification, it is primarily the first component that has been addressed with regard to optimal sensor placement. In this particular context, a common approach is to distribute sensors, of which the amount is determined a priori, such that some scalar function of the probability of detection for a pre......-defined set of damage patterns is maximized. Obviously, the optimal sensor distribution, in terms of damage detection, is algorithm-dependent, but studies have showed how correlation generally exists between the different strategies. However, it still remains a question how this “optimality” correlates...

An Ultrasonic Wireless Sensor Network for Data Communication and Structural Health Monitoring, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Typical Structural Health Monitoring (SHM) uses embedded ultrasonic transducers exclusively for non-destructive evaluation (NDE) purposes, whereas data transfer is...

Historic Bim: a New Repository for Structural Health Monitoring

Science.gov (United States)

Banfi, F.; Barazzetti, L.; Previtali, M.; Roncoroni, F.

2017-05-01

Recent developments in Building Information Modelling (BIM) technologies are facilitating the management of historic complex structures using new applications. This paper proposes a generative method combining the morphological and typological aspects of the historic buildings (H-BIM), with a set of monitoring information. This combination of 3D digital survey, parametric modelling and monitoring datasets allows for the development of a system for archiving and visualizing structural health monitoring (SHM) data (Fig. 1). The availability of a BIM database allows one to integrate a different kind of data stored in different ways (e.g. reports, tables, graphs, etc.) with a representation directly connected to the 3D model of the structure with appropriate levels of detail (LoD). Data can be interactively accessed by selecting specific objects of the BIM, i.e. connecting the 3D position of the sensors installed with additional digital documentation. Such innovative BIM objects, which form a new BIM family for SHM, can be then reused in other projects, facilitating data archiving and exploitation of data acquired and processed. The application of advanced modeling techniques allows for the reduction of time and costs of the generation process, and support cooperation between different disciplines using a central workspace. However, it also reveals new challenges for parametric software and exchange formats. The case study presented is the medieval bridge Azzone Visconti in Lecco (Italy), in which multi-temporal vertical movements during load testing were integrated into H-BIM.

HISTORIC BIM: A NEW REPOSITORY FOR STRUCTURAL HEALTH MONITORING

Directory of Open Access Journals (Sweden)

F. Banfi

2017-05-01

Full Text Available Recent developments in Building Information Modelling (BIM technologies are facilitating the management of historic complex structures using new applications. This paper proposes a generative method combining the morphological and typological aspects of the historic buildings (H-BIM, with a set of monitoring information. This combination of 3D digital survey, parametric modelling and monitoring datasets allows for the development of a system for archiving and visualizing structural health monitoring (SHM data (Fig. 1. The availability of a BIM database allows one to integrate a different kind of data stored in different ways (e.g. reports, tables, graphs, etc. with a representation directly connected to the 3D model of the structure with appropriate levels of detail (LoD. Data can be interactively accessed by selecting specific objects of the BIM, i.e. connecting the 3D position of the sensors installed with additional digital documentation. Such innovative BIM objects, which form a new BIM family for SHM, can be then reused in other projects, facilitating data archiving and exploitation of data acquired and processed. The application of advanced modeling techniques allows for the reduction of time and costs of the generation process, and support cooperation between different disciplines using a central workspace. However, it also reveals new challenges for parametric software and exchange formats. The case study presented is the medieval bridge Azzone Visconti in Lecco (Italy, in which multi-temporal vertical movements during load testing were integrated into H-BIM.

Vibration monitoring of long bridges and their expansion joints and seismic devices

OpenAIRE

Islami Kleidi

2015-01-01

This paper presents a number of recently installed Structural Health Monitoring (SHM) systems: a) on a 2km double suspension bridge; b) on a long railway viaduct that has experienced cracking; and c) on a steel arch bridge in a seismically active area. Damage detection techniques have been applied based on high-frequency measurements of vibrations, pressure and strain, enabling a proper understanding of the structures’ behaviour to be gained. The diverse range of applications presented, desig...

Structural Health Monitoring of Nuclear Spent Fuel Storage Facilities

Energy Technology Data Exchange (ETDEWEB)

Yu, Lingyu

2018-04-10

Interim storage of spent nuclear fuel from reactor sites has gained additional importance and urgency for resolving waste-management-related technical issues. To ensure that nuclear power remains clean energy, monitoring has been identified by DOE as a high priority cross-cutting need, necessary to determine and predict the degradation state of the systems, structures, and components (SSCs) important to safety (ITS). Therefore, nondestructive structural condition monitoring becomes a need to be installed on existing or to be integrated into future storage system to quantify the state of health or to guarantee the safe operation of nuclear power plants (NPPs) during their extended life span. In this project, the lead university and the collaborating national laboratory teamed to develop a nuclear structural health monitoring (n-SHM) system based on in-situ piezoelectric sensing technologies that can monitor structural degradation and aging for nuclear spent fuel DCSS and similar structures. We also aimed to identify and quantify possible influences of nuclear spent fuel environment (temperature and radiation) to the piezoelectric sensor system and come up with adequate solutions and guidelines therefore. We have therefore developed analytical model for piezoelectric based n-SHM methods, with considerations of temperature and irradiation influence on the model of sensing and algorithms in acoustic emission (AE), guided ultrasonic waves (GUW), and electromechanical impedance spectroscopy (EMIS). On the other side, experimentally the temperature and irradiation influence on the piezoelectric sensors and sensing capabilities were investigated. Both short-term and long-term irradiation investigation with our collaborating national laboratory were performed. Moreover, we developed multi-modal sensing, validated in laboratory setup, and conducted the testing on the We performed multi-modal sensing development, verification and validation tests on very complex structures

X-33/RLV System Health Management/Vehicle Health Management

Science.gov (United States)

Mouyos, William; Wangu, Srimal

1998-01-01

To reduce operations costs, Reusable Launch Vehicles (RLVS) must include highly reliable robust subsystems which are designed for simple repair access with a simplified servicing infrastructure, and which incorporate expedited decision-making about faults and anomalies. A key component for the Single Stage To Orbit (SSTO) RLV system used to meet these objectives is System Health Management (SHM). SHM incorporates Vehicle Health Management (VHM), ground processing associated with the vehicle fleet (GVHM), and Ground Infrastructure Health Management (GIHM). The primary objective of SHM is to provide an automated and paperless health decision, maintenance, and logistics system. Sanders, a Lockheed Martin Company, is leading the design, development, and integration of the SHM system for RLV and for X-33 (a sub-scale, sub-orbit Advanced Technology Demonstrator). Many critical technologies are necessary to make SHM (and more specifically VHM) practical, reliable, and cost effective. This paper will present the X-33 SHM design which forms the baseline for the RLV SHM, and it will discuss applications of advanced technologies to future RLVs. In addition, this paper will describe a Virtual Design Environment (VDE) which is being developed for RLV. This VDE will allow for system design engineering, as well as program management teams, to accurately and efficiently evaluate system designs, analyze the behavior of current systems, and predict the feasibility of making smooth and cost-efficient transitions from older technologies to newer ones. The RLV SHM design methodology will reduce program costs, decrease total program life-cycle time, and ultimately increase mission success.

An Improved Gaussian Mixture Model for Damage Propagation Monitoring of an Aircraft Wing Spar under Changing Structural Boundary Conditions

Science.gov (United States)

Qiu, Lei; Yuan, Shenfang; Mei, Hanfei; Fang, Fang

2016-01-01

Structural Health Monitoring (SHM) technology is considered to be a key technology to reduce the maintenance cost and meanwhile ensure the operational safety of aircraft structures. It has gradually developed from theoretic and fundamental research to real-world engineering applications in recent decades. The problem of reliable damage monitoring under time-varying conditions is a main issue for the aerospace engineering applications of SHM technology. Among the existing SHM methods, Guided Wave (GW) and piezoelectric sensor-based SHM technique is a promising method due to its high damage sensitivity and long monitoring range. Nevertheless the reliability problem should be addressed. Several methods including environmental parameter compensation, baseline signal dependency reduction and data normalization, have been well studied but limitations remain. This paper proposes a damage propagation monitoring method based on an improved Gaussian Mixture Model (GMM). It can be used on-line without any structural mechanical model and a priori knowledge of damage and time-varying conditions. With this method, a baseline GMM is constructed first based on the GW features obtained under time-varying conditions when the structure under monitoring is in the healthy state. When a new GW feature is obtained during the on-line damage monitoring process, the GMM can be updated by an adaptive migration mechanism including dynamic learning and Gaussian components split-merge. The mixture probability distribution structure of the GMM and the number of Gaussian components can be optimized adaptively. Then an on-line GMM can be obtained. Finally, a best match based Kullback-Leibler (KL) divergence is studied to measure the migration degree between the baseline GMM and the on-line GMM to reveal the weak cumulative changes of the damage propagation mixed in the time-varying influence. A wing spar of an aircraft is used to validate the proposed method. The results indicate that the crack

A regime-switching cointegration approach for removing environmental and operational variations in structural health monitoring

Science.gov (United States)

Shi, Haichen; Worden, Keith; Cross, Elizabeth J.

2018-03-01

Cointegration is now extensively used to model the long term common trends among economic variables in the field of econometrics. Recently, cointegration has been successfully implemented in the context of structural health monitoring (SHM), where it has been used to remove the confounding influences of environmental and operational variations (EOVs) that can often mask the signature of structural damage. However, restrained by its linear nature, the conventional cointegration approach has limited power in modelling systems where measurands are nonlinearly related; this occurs, for example, in the benchmark study of the Z24 Bridge, where nonlinear relationships between natural frequencies were induced during a period of very cold temperatures. To allow the removal of EOVs from SHM data with nonlinear relationships like this, this paper extends the well-established cointegration method to a nonlinear context, which is to allow a breakpoint in the cointegrating vector. In a novel approach, the augmented Dickey-Fuller (ADF) statistic is used to find which position is most appropriate for inserting a breakpoint, the Johansen procedure is then utilised for the estimation of cointegrating vectors. The proposed approach is examined with a simulated case and real SHM data from the Z24 Bridge, demonstrating that the EOVs can be neatly eliminated.

Data driven innovations in structural health monitoring

Science.gov (United States)

Rosales, M. J.; Liyanapathirana, R.

2017-05-01

At present, substantial investments are being allocated to civil infrastructures also considered as valuable assets at a national or global scale. Structural Health Monitoring (SHM) is an indispensable tool required to ensure the performance and safety of these structures based on measured response parameters. The research to date on damage assessment has tended to focus on the utilization of wireless sensor networks (WSN) as it proves to be the best alternative over the traditional visual inspections and tethered or wired counterparts. Over the last decade, the structural health and behaviour of innumerable infrastructure has been measured and evaluated owing to several successful ventures of implementing these sensor networks. Various monitoring systems have the capability to rapidly transmit, measure, and store large capacities of data. The amount of data collected from these networks have eventually been unmanageable which paved the way to other relevant issues such as data quality, relevance, re-use, and decision support. There is an increasing need to integrate new technologies in order to automate the evaluation processes as well as to enhance the objectivity of data assessment routines. This paper aims to identify feasible methodologies towards the application of time-series analysis techniques to judiciously exploit the vast amount of readily available as well as the upcoming data resources. It continues the momentum of a greater effort to collect and archive SHM approaches that will serve as data-driven innovations for the assessment of damage through efficient algorithms and data analytics.

A Review of the Piezoelectric Electromechanical Impedance Based Structural Health Monitoring Technique for Engineering Structures

Directory of Open Access Journals (Sweden)

Wongi S. Na

2018-04-01

Full Text Available The birth of smart materials such as piezoelectric (PZT transducers has aided in revolutionizing the field of structural health monitoring (SHM based on non-destructive testing (NDT methods. While a relatively new NDT method known as the electromechanical (EMI technique has been investigated for more than two decades, there are still various problems that must be solved before it is applied to real structures. The technique, which has a significant potential to contribute to the creation of one of the most effective SHM systems, involves the use of a single PZT for exciting and sensing of the host structure. In this paper, studies applied for the past decade related to the EMI technique have been reviewed to understand its trend. In addition, new concepts and ideas proposed by various authors are also surveyed, and the paper concludes with a discussion of the potential directions for future works.

Crack diagnosis of metallic profiles based on structural damage indicators

International Nuclear Information System (INIS)

Preisler, A; Schröder, K-U; Steenbock, C

2015-01-01

Structural Health Monitoring (SHM) faces several challenges before large-scale industrial application. First of all damage diagnosis has to be reliable. Therefore, common SHM approaches use highly advanced sensor techniques to monitor the whole structure on all possible failures. This results in an enormous amount of data gathered during service. The general effort can be drastically reduced, if the knowledge achieved during the sizing process is used. During sizing, potential failure modes and critical locations, so called hot spots, are already evaluated. A very sensitive SHM system can be developed, when the monitoring effort shifts from the damage to its impact on the structural behaviour and the so called damage indicators. These are the two main components of the SmartSHM approach, which reduces the monitoring effort significantly. Not only the amount of data is minimized, but also reliability and robustness are ensured by the SmartSHM approach.This contribution demonstrates the SmartSHM approach by a cracked four point bending beam. To show general applicability a parametric study considering different profiles (bar, box, I, C, T, L, Z), crack positions and lengths has been performed. Questions of sensitivity and minimum size of the sensor network are discussed based on the results of the parametric study. (paper)

Towards Real-time, On-board, Hardware-Supported Sensor and Software Health Management for Unmanned Aerial Systems

Science.gov (United States)

Schumann, Johann; Rozier, Kristin Y.; Reinbacher, Thomas; Mengshoel, Ole J.; Mbaya, Timmy; Ippolito, Corey

2013-01-01

Unmanned aerial systems (UASs) can only be deployed if they can effectively complete their missions and respond to failures and uncertain environmental conditions while maintaining safety with respect to other aircraft as well as humans and property on the ground. In this paper, we design a real-time, on-board system health management (SHM) capability to continuously monitor sensors, software, and hardware components for detection and diagnosis of failures and violations of safety or performance rules during the flight of a UAS. Our approach to SHM is three-pronged, providing: (1) real-time monitoring of sensor and/or software signals; (2) signal analysis, preprocessing, and advanced on the- fly temporal and Bayesian probabilistic fault diagnosis; (3) an unobtrusive, lightweight, read-only, low-power realization using Field Programmable Gate Arrays (FPGAs) that avoids overburdening limited computing resources or costly re-certification of flight software due to instrumentation. Our implementation provides a novel approach of combining modular building blocks, integrating responsive runtime monitoring of temporal logic system safety requirements with model-based diagnosis and Bayesian network-based probabilistic analysis. We demonstrate this approach using actual data from the NASA Swift UAS, an experimental all-electric aircraft.

Experimental system identification of the dynamics of a vibro-impact beam with a view towards structural health monitoring and damage detection

Science.gov (United States)

Chen, Heng; Kurt, Mehmet; Lee, Young S.; McFarland, D. Michael; Bergman, Lawrence A.; Vakakis, Alexander F.

2014-05-01

We perform nonlinear system identification (NSI) on the acceleration signals that were experimentally measured at ten, almost evenly spaced positions along a cantilever beam undergoing vibro-impacts between two rigid stops with clearances. Our goal is to characterize the nonlinear dynamics due to vibro-impacts with a view toward structural health monitoring (SHM) and damage detection (DD). The NSI methodology is based on the correspondence between analytical and empirical slow-flow dynamics, with the first step requiring empirical mode decomposition (EMD) analysis of the measured time series leading to sets of intrinsic modal oscillators (IMOs) governing the vibro-impact dynamics at different time scales. By comparing the spatiotemporal variations of the nonlinear modal interactions (and hence the IMOs), we examine how vibro-impacts influence the low- and high-frequency modes in global and local senses. In applications of the NSI results to SHM/DD, we calculate typical measures such as the modal assurance criterion (MAC) and the coordinate modal assurance criterion (COMAC) by extracting information about the mode shape functions from the spatiotemporal IMO solutions. Whereas the MAC provides a global aspect of damage occurrence (i.e., which modes are more affected by induced defects), the COMAC can narrow down the damage locations (i.e., where in the structure defects exist that yield low correlation values in specific modes).

Damage assessment using flexibility and flexibility-based curvature for structural health monitoring

International Nuclear Information System (INIS)

Catbas, F N; Gul, M; Burkett, J L

2008-01-01

As a result of the recent advances in sensors, information technologies and material science, a considerable amount of research has been conducted in the area of smart infrastructures. While there are many important components of a smart infrastructure, an automated and continuous structural health monitoring (SHM) system is a critical one. SHM is typically used to track and evaluate the performance of a structure, symptoms of operational incidents, anomalies due to deterioration and damage during regular operation as well as after an extreme event. Successful health monitoring applications can be achieved by integrating experimental, analytical and information technologies on real-life operating structures. However, real-life investigations must be backed up by laboratory benchmark studies for validating theory, concepts, and new technologies. For this reason, a physical bridge model is developed to implement SHM methods and technologies. In this study, different aspects of model development are outlined in terms of design considerations, instrumentation, finite element modeling, and simulating damage scenarios. Different damage detection methods are evaluated using the numerical and the physical models. Modal parameter estimation studies are carried out to reliably identify the eigenvalues, eigenvectors and modal scaling from the measurement data. To assess the simulated damage, modal flexibility-based displacements and curvatures are employed. Structural behavior after damage is evaluated by inspecting the deflected shapes obtained using modal flexibility. More localized damage simulations such as stiffness reduction at a joint yield a very subtle stiffness decrease. In this case, the writers use a baseline to identify damage and also investigate the use of curvature as a complementary index. Curvature is advantageous for certain cases where the displacement results do not provide substantial changes. Issues related to using curvature as a damage identification

Optical fiber sensors FBG to the structural health monitoring of bridges

International Nuclear Information System (INIS)

Navarro-Henriquez, Francisco

2014-01-01

Systems with optical fiber sensors FBG (Fiber Bragg Grating) are consolidated in the Structural Health Monitoring (SHM) of bridges, static and dynamic nondestructive testing with measurements of deformation, displacement, deflection, temperature and vibrations. A brief introduction to the technology is presented and the fundamentals of optical fiber sensors, their use and comparative advantages over its traditional counterpart. The practice of the FBG sensor application is described. The characteristics of these sensors and measurement graphics are presented. Some key aspects to consider for proper use in the field are mentioned. (author) [es

Spectral element modelling of wave propagation in isotropic and anisotropic shell-structures including different types of damage

International Nuclear Information System (INIS)

Schulte, R T; Fritzen, C-P; Moll, J

2010-01-01

During the last decades, guided waves have shown great potential for Structural Health Monitoring (SHM) applications. These waves can be excited and sensed by piezoelectric elements that can be permanently attached onto a structure offering online monitoring capability. However, the setup of wave based SHM systems for complex structures may be very difficult and time consuming. For that reason there is a growing demand for efficient simulation tools providing the opportunity to design wave based SHM systems in a virtual environment. As usually high frequency waves are used, the associated short wavelength leads to the necessity of a very dense mesh, which makes conventional finite elements not well suited for this purpose. Therefore in this contribution a flat shell spectral element approach is presented. By including electromechanical coupling a SHM system can be simulated entirely from actuator voltage to sensor voltage. Besides a comparison to measured data for anisotropic materials including delamination, a numerical example of a more complex, stiffened shell structure with debonding is presented.

The use of an improved technique to reduce the variability of output voltage in real-time Fibre Bragg Grating based monitoring system

Science.gov (United States)

Vorathin, E.; Hafizi, Z. M.; Che Ghani, S. A.; Lim, K. S.; Aizzuddin, A. M.

2017-10-01

Fibre Bragg Grating (FBG) sensors have been widely utilized in the structural health monitoring (SHM) of structures. However, one of the main challenges of FBGs is the existence of inconsistency in output voltage during wavelength intensity demodulation utilizing photodetector (PD) to convert the light signal into digital voltage readings. Thus, the designation of this experimental work is to develop a robust FBG real-time monitoring system with the benefit of MATLAB graphical user interface (GUI) and voltage normalization algorithm to scale down the voltage inconsistency. Low-cost edge filter interrogation system has been practiced in the experimentation and splitter optical component is make use to reduce the intensity of the high power light source that leads to the formation of noise due to unwanted reflected wavelengths. The results revealed that with the advancement of the proposed monitoring system, the sensitivity of the FBG has been increased from 2.4 mV/N to 3.8 mV/N across the range of 50 N. The redundancy in output voltage variation data points has been reduced from 26 data/minute to 17 data/minute. The accuracy of the FBG in detecting the load induced falls in the acceptable range of total average error which is 1.38 %.

Experimental Investigation on Admittance-Based Piezoelectric Sensor Diagnostic Process

Energy Technology Data Exchange (ETDEWEB)

Jo, Hyejin; Park, Tongil; Park, Gyuhae [Chonnam National University, Gwangju (Korea, Republic of)

2015-01-15

Structural health monitoring (SHM) techniques based on the use of active-sensing piezoelectric (PZT) materials have received considerable attention. The validation of the PZT functionality during SHM operation is critical to successfully implementing a reliable SHM system. In this study, we investigated several parameters that affect the admittance-based sensor diagnostic process. We experimentally identified the temperature dependency of the active-sensor diagnostic process. We found that the admittance-based sensor diagnostic process can differentiate the adhesion conditions of bonding materials that are used to install a PZT on a structure, which is important when designing a sensor diagnostic process for an SHM system.

Multi-Wave and Hybrid Imaging Techniques: A New Direction for Nondestructive Testing and Structural Health Monitoring

Directory of Open Access Journals (Sweden)

Yuhua Cheng

2013-11-01

Full Text Available In this article, the state-of-the-art multi-wave and hybrid imaging techniques in the field of nondestructive evaluation and structural health monitoring were comprehensively reviewed. A new direction for assessment and health monitoring of various structures by capitalizing the advantages of those imaging methods was discussed. Although sharing similar system configurations, the imaging physics and principles of multi-wave phenomena and hybrid imaging methods are inherently different. After a brief introduction of nondestructive evaluation (NDE , structure health monitoring (SHM and their related challenges, several recent advances that have significantly extended imaging methods from laboratory development into practical applications were summarized, followed by conclusions and discussion on future directions.

Health monitoring of 90° bolted joints using fuzzy pattern recognition of ultrasonic signals

International Nuclear Information System (INIS)

Jalalpour, M; El-Osery, A I; Austin, E M; Reda Taha, M M

2014-01-01

Bolted joints are important parts for aerospace structures. However, there is a significant risk associated with assembling bolted joints due to potential human error during the assembly process. Such errors are expensive to find and correct if exposed during environmental testing, yet checking the integrity of individual fasteners after assembly would be a time consuming task. Recent advances in structural health monitoring (SHM) can provide techniques to not only automate this process but also make it reliable. This integrity monitoring requires damage features to be related to physical conditions representing the structural integrity of bolted joints. In this paper an SHM technique using ultrasonic signals and fuzzy pattern recognition to monitor the integrity of 90° bolted joints in aerospace structures is described. The proposed technique is based on normalized fast Fourier transform (NFFT) of transmitted signals and fuzzy pattern recognition. Moreover, experimental observations of a case study on an aluminum 90° bolted joint are presented. We demonstrate the ability of the proposed method to efficiently monitor and indicate bolted joint integrity. (paper)

Vibration-based monitoring and diagnostics using compressive sensing

Science.gov (United States)

Ganesan, Vaahini; Das, Tuhin; Rahnavard, Nazanin; Kauffman, Jeffrey L.

2017-04-01

Vibration data from mechanical systems carry important information that is useful for characterization and diagnosis. Standard approaches rely on continually streaming data at a fixed sampling frequency. For applications involving continuous monitoring, such as Structural Health Monitoring (SHM), such approaches result in high volume data and rely on sensors being powered for prolonged durations. Furthermore, for spatial resolution, structures are instrumented with a large array of sensors. This paper shows that both volume of data and number of sensors can be reduced significantly by applying Compressive Sensing (CS) in vibration monitoring applications. The reduction is achieved by using random sampling and capitalizing on the sparsity of vibration signals in the frequency domain. Preliminary experimental results validating CS-based frequency recovery are also provided. By exploiting the sparsity of mode shapes, CS can also enable efficient spatial reconstruction using fewer spatially distributed sensors. CS can thereby reduce the cost and power requirement of sensing as well as streamline data storage and processing in monitoring applications. In well-instrumented structures, CS can enable continued monitoring in case of sensor or computational failures.

Manufacturing technology of integrated textile-based sensor networks for in situ monitoring applications of composite wind turbine blades

Science.gov (United States)

Haentzsche, Eric; Mueller, Ralf; Huebner, Matthias; Ruder, Tristan; Unger, Reimar; Nocke, Andreas; Cherif, Chokri

2016-10-01

Based on in situ strain sensors consisting of piezo-resistive carbon filament yarns (CFYs), which have been successfully integrated into textile reinforcement structures during their textile-technological manufacturing process, a continuous load of fibre-reinforced plastic (FRP) components has been realised. These sensors are also suitable for structural health monitoring (SHM) applications. The two-dimensional sensor layout is made feasible by the usage of a modular warp yarn path manipulation unit. Using a functional model of a small wind turbine blade in thermoset composite design, the sensor function for basic SHM applications (e.g. static load monitoring) are demonstrated. Any mechanical loads along the pressure or suction side of the wind turbine blade can be measured and calculated via a correlative change in resistance of the CFYs within the textile reinforcement plies. Performing quasi-static load tests on both tensile specimen and full-scale wind turbine blade, elementary results have been obtained concerning electro-mechanical behaviour and spatial resolution of global and even local static stresses according to the CFY sensor integration length. This paper demonstrates the great potential of textile-based and textile-technological integrated sensors in reinforcement structures for future SHM applications of FRPs.

A bio-inspired asynchronous skin system for crack detection applications

International Nuclear Information System (INIS)

Sharp, Nathan; Kuntz, Alan; Brubaker, Cole; Amos, Stephanie; Gao, Wei; Gupta, Gautum; Mohite, Aditya; Farrar, Charles; Mascareñas, David

2014-01-01

In many applications of structural health monitoring (SHM) it is imperative or advantageous to have large sensor arrays in order to properly sense the state of health of the structure. Typically these sensor networks are implemented by placing a large number of sensors over a structure and running individual cables from each sensor back to a central measurement station. Data is then collected from each sensor on the network at a constant sampling rate regardless of the current timescales at which events are acting on the structure. These conventional SHM sensor networks have a number of shortfalls. They tend to have a large number of cables that can represent a single point of failure for each sensor as well as add significant weight and installation costs. The constant sampling rate associated with each sensor very quickly leads to large amounts of data that must be analyzed, stored, and possibly transmitted to a remote user. This leads to increased demands on power consumption, bandwidth, and size. It also taxes our current techniques for managing large amounts of data. For the last decade the goal of the SHM community has been to endow structures with the functionality of a biological nervous system. Despite this goal the community has predominantly ignored the biological nervous system as inspiration for building structural nervous systems, choosing instead to focus on experimental mechanics and simulation techniques. In this work we explore the use of a novel, bio-inspired, SHM skin. This skin makes use of distributed computing and asynchronous communication techniques to alleviate the scale of the data management challenge as well as reduce power. The system also periodically sends a ‘heat beat’ signal to provide state-of-health updates. This conductive skin was implemented using conductive ink resistors as well as with graphene-oxide capacitors. (paper)

Stochastic change detection in uncertain nonlinear systems using reduced-order models: classification

International Nuclear Information System (INIS)

Yun, Hae-Bum; Masri, Sami F

2009-01-01

A reliable structural health monitoring methodology (SHM) is proposed to detect relatively small changes in uncertain nonlinear systems. A total of 4000 physical tests were performed using a complex nonlinear magneto-rheological (MR) damper. With the effective (or 'genuine') changes and uncertainties in the system characteristics of the semi-active MR damper, which were precisely controlled with known means and standard deviation of the input current, the tested MR damper was identified with the restoring force method (RFM), a non-parametric system identification method involving two-dimensional orthogonal polynomials. Using the identified RFM coefficients, both supervised and unsupervised pattern recognition techniques (including support vector classification and k-means clustering) were employed to detect system changes in the MR damper. The classification results showed that the identified coefficients with orthogonal basis function can be used as reliable indicators for detecting (small) changes, interpreting the physical meaning of the detected changes without a priori knowledge of the monitored system and quantifying the uncertainty bounds of the detected changes. The classification errors were analyzed using the standard detection theory to evaluate the performance of the developed SHM methodology. An optimal classifier design procedure was also proposed and evaluated to minimize type II (or 'missed') errors

Wireless AE Event and Environmental Monitoring for Wind Turbine Blades at Low Sampling Rates

Science.gov (United States)

Bouzid, Omar M.; Tian, Gui Y.; Cumanan, K.; Neasham, J.

Integration of acoustic wireless technology in structural health monitoring (SHM) applications introduces new challenges due to requirements of high sampling rates, additional communication bandwidth, memory space, and power resources. In order to circumvent these challenges, this chapter proposes a novel solution through building a wireless SHM technique in conjunction with acoustic emission (AE) with field deployment on the structure of a wind turbine. This solution requires a low sampling rate which is lower than the Nyquist rate. In addition, features extracted from aliased AE signals instead of reconstructing the original signals on-board the wireless nodes are exploited to monitor AE events, such as wind, rain, strong hail, and bird strike in different environmental conditions in conjunction with artificial AE sources. Time feature extraction algorithm, in addition to the principal component analysis (PCA) method, is used to extract and classify the relevant information, which in turn is used to classify or recognise a testing condition that is represented by the response signals. This proposed novel technique yields a significant data reduction during the monitoring process of wind turbine blades.

Structural health monitoring of civil infrastructure using optical fiber sensing technology: a comprehensive review.

Science.gov (United States)

Ye, X W; Su, Y H; Han, J P

2014-01-01

In the last two decades, a significant number of innovative sensing systems based on optical fiber sensors have been exploited in the engineering community due to their inherent distinctive advantages such as small size, light weight, immunity to electromagnetic interference (EMI) and corrosion, and embedding capability. A lot of optical fiber sensor-based monitoring systems have been developed for continuous measurement and real-time assessment of diversified engineering structures such as bridges, buildings, tunnels, pipelines, wind turbines, railway infrastructure, and geotechnical structures. The purpose of this review article is devoted to presenting a summary of the basic principles of various optical fiber sensors, innovation in sensing and computational methodologies, development of novel optical fiber sensors, and the practical application status of the optical fiber sensing technology in structural health monitoring (SHM) of civil infrastructure.

Vibration monitoring of long bridges and their expansion joints and seismic devices

Directory of Open Access Journals (Sweden)

Islami Kleidi

2015-01-01

Full Text Available This paper presents a number of recently installed Structural Health Monitoring (SHM systems: a on a 2km double suspension bridge; b on a long railway viaduct that has experienced cracking; and c on a steel arch bridge in a seismically active area. Damage detection techniques have been applied based on high-frequency measurements of vibrations, pressure and strain, enabling a proper understanding of the structures’ behaviour to be gained. The diverse range of applications presented, designed in collaboration with structure owners and design engineers, includes damage detection on expansion joints of suspension bridges, crack analysis and correlation with accelerations of high-speed trains, and high-frequency performance monitoring of seismic devices. These case studies, based on both static and dynamic approaches, demonstrate the usefulness and ease of use of such systems, and the enormous gains in efficiency they offer.

Knowledge Discovery from Vibration Measurements

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Jun Deng

2014-01-01

Full Text Available The framework as well as the particular algorithms of pattern recognition process is widely adopted in structural health monitoring (SHM. However, as a part of the overall process of knowledge discovery from data bases (KDD, the results of pattern recognition are only changes and patterns of changes of data features. In this paper, based on the similarity between KDD and SHM and considering the particularity of SHM problems, a four-step framework of SHM is proposed which extends the final goal of SHM from detecting damages to extracting knowledge to facilitate decision making. The purposes and proper methods of each step of this framework are discussed. To demonstrate the proposed SHM framework, a specific SHM method which is composed by the second order structural parameter identification, statistical control chart analysis, and system reliability analysis is then presented. To examine the performance of this SHM method, real sensor data measured from a lab size steel bridge model structure are used. The developed four-step framework of SHM has the potential to clarify the process of SHM to facilitate the further development of SHM techniques.

Structural health monitoring of compression connectors for overhead transmission lines

Science.gov (United States)

Wang, Hong; Wang, Jy-An John; Swindeman, Joseph P.; Ren, Fei; Chan, John

2017-04-01

Two-stage aluminum conductor steel-reinforced (ACSR) compression connectors are extensively used in US overhead transmission lines. The connectors are made by crimping a steel sleeve onto a steel core and an aluminum sleeve over electrical conducting aluminum strands. The connectors are designed to operate at temperatures up to 125°C, but their performance is increasingly degrading because of overloading of lines. Currently, electric utilities conduct routine line inspections using thermal and electrical measurements, but these methods do not provide information about the structural integrity of connectors. In this work, structural health monitoring (SHM) of compression connectors was studied using electromechanical impedance (EMI) analysis. Lead zirconate titanate (PZT)-5A was identified as a smart material for SHM. A flexible high-temperature bonding layer was used to address challenges in PZT integration due to a significant difference in the coefficients of thermal expansion of PZT and the aluminum substrate. The steel joint on the steel core was investigated because it is responsible for the ultimate tensile strength of the connector. Tensile testing was used to induce structural damage to the joint, or steel core pullout, and thermal cycling introduced additional structural perturbations. EMI measurements were conducted between the tests. The root mean square deviation (RMSD) of EMI was identified as a damage index. The use of steel joints has been shown to enable SHM under simulated conditions. The EMI signature is sensitive to variations in structural conditions. RMSD can be correlated to the structural health of a connector and has potential for use in the SHM and structural integrity evaluation.

Experimental Research on Quick Structural Health Monitoring Technique for Bridges Using Smartphone

OpenAIRE

Zhao, Xuefeng; Ri, Kwang; Han, Ruicong; Yu, Yan; Li, Mingchu; Ou, Jinping

2016-01-01

In the recent years, with the development and popularization of smartphone, the utilization of smartphone in the Structural Health Monitoring (SHM) has attracted increasing attention owing to its unique feature. Since bridges are of great importance to society and economy, bridge health monitoring has very practical significance during its service life. Furthermore, rapid damage assessment of bridge after an extreme event such as earthquake is very important in the recovery work. Smartphone-b...

Remote monitoring of bond line defects between a composite panel and a stiffener using distributed piezoelectric sensors

Science.gov (United States)

Yu, Xudong; Fan, Zheng; Puliyakote, Sreedhar; Castaings, Michel

2018-03-01

Structural health monitoring (SHM) using ultrasonic guided waves has proven to be attractive for the identification of damage in composite plate-like structures, due to its realization of both significant propagation distances and reasonable sensitivity to defects. However, topographical features such as bends, lap joints, and bonded stiffeners are often encountered in these structures, and they are susceptible to various types of defects as a consequence of stress concentration and cyclic loading during the service life. Therefore, the health condition of such features has to be assessed effectively to ensure the safe operation of the entire structure. This paper proposes a novel feature guided wave (FGW) based SHM strategy, in which proper FGWs are exploited as a screening tool to rapidly interrogate the representative stiffener-adhesive bond-composite skin assembly. An array of sensors permanently attached to the vicinity of the feature is used to capture scattered waves from the localized damage occurring in the bond line. This technique is combined with an imaging approach, and the damage reconstruction is achieved by the synthetic focusing algorithm using these scattered signals. The proposed SHM scheme is implemented in both the 3D finite element simulation and the experiment, and the results are in good agreement, demonstrating the feasibility of such SHM strategy.

Random demodulation for structural health monitoring excited by the five-cycle sine burst

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Li Xing

2017-01-01

Full Text Available Nowadays, the Structural Health Monitoring (SHM has been paid more and more attention. The five-cycle sine burst is widely used as the exciting signal in SHM and the sensors’ responded signals are analyzed to research the damage. In the sensor network, there will be many sensors which mean many responded signals will be sampled, restored and sometimes transferred. In the traditional way which is known as Nyquist sampling theorem, the sampling rate must be more than twice the highest rate of the original signal. In this way, the amount of data will be huge. As the result, the costs will be very expensive and the equipment may be huge and heavy, which is especially unaccepted in the aircraft. It is necessary to do some research to compress the signal. The Compressing Sensing (CS theory provides new methods to compress the signals. The Random Demodulation (RD is a specific method which can accomplish the physical implementation of CS theory. In this paper, according to the structure of RD, we chose some chips to build a RD system. And we did some experiments to verify the method through the system. We chose the Orthogonal Matching Pursuit (OMP as the construct algorithm to recover the signal.

A Multiscale Finite Element Model Validation Method of Composite Cable-Stayed Bridge Based on Structural Health Monitoring System

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Rumian Zhong

2015-01-01

Full Text Available A two-step response surface method for multiscale finite element model (FEM updating and validation is presented with respect to Guanhe Bridge, a composite cable-stayed bridge in the National Highway number G15, in China. Firstly, the state equations of both multiscale and single-scale FEM are established based on the basic equation in structural dynamic mechanics to update the multiscale coupling parameters and structural parameters. Secondly, based on the measured data from the structural health monitoring (SHM system, a Monte Carlo simulation is employed to analyze the uncertainty quantification and transmission, where the uncertainties of the multiscale FEM and measured data were considered. The results indicate that the relative errors between the calculated and measured frequencies are less than 2%, and the overlap ratio indexes of each modal frequency are larger than 80% without the average absolute value of relative errors. These demonstrate that the proposed method can be applied to validate the multiscale FEM, and the validated FEM can reflect the current conditions of the real bridge; thus it can be used as the basis for bridge health monitoring, damage prognosis (DP, and safety prognosis (SP.

Impedance-based damage assessment using piezoelectric sensors

Science.gov (United States)

Rim, Mi-Sun; Yoo, Seung-Jae; Lee, In; Song, Jae-Hoon; Yang, Jae-Won

2011-04-01

Recently structural health monitoring (SHM) systems are being focused because they make it possible to assess the health of structures at real-time in many application fields such as aircraft, aerospace, civil and so on. Piezoelectric materials are widely used for sensors of SHM system to monitor damage of critical parts such as bolted joints. Bolted joints could be loosened by vibration, thermal cycling, shock, corrosion, and they cause serious mechanical failures. In this paper, impedance-based method using piezoelectric sensors was applied for real-time SHM. A steel beam specimen fastened by bolts was tested, and polymer type piezoelectric materials, PVDFs were used for sensors to monitor the condition of bolted joint connections. When structure has some damage, for example loose bolts, the impedance of PVDF sensors showed different tendency with normal structure which has no loose bolts. In the case of loose bolts, impedance values are decreased and admittance values are increased.

Structural Health Monitoring of Civil Infrastructure Using Optical Fiber Sensing Technology: A Comprehensive Review

Science.gov (United States)

Ye, X. W.; Su, Y. H.; Han, J. P.

2014-01-01

In the last two decades, a significant number of innovative sensing systems based on optical fiber sensors have been exploited in the engineering community due to their inherent distinctive advantages such as small size, light weight, immunity to electromagnetic interference (EMI) and corrosion, and embedding capability. A lot of optical fiber sensor-based monitoring systems have been developed for continuous measurement and real-time assessment of diversified engineering structures such as bridges, buildings, tunnels, pipelines, wind turbines, railway infrastructure, and geotechnical structures. The purpose of this review article is devoted to presenting a summary of the basic principles of various optical fiber sensors, innovation in sensing and computational methodologies, development of novel optical fiber sensors, and the practical application status of the optical fiber sensing technology in structural health monitoring (SHM) of civil infrastructure. PMID:25133250

Structural Health Monitoring of Civil Infrastructure Using Optical Fiber Sensing Technology: A Comprehensive Review

Directory of Open Access Journals (Sweden)

X. W. Ye

2014-01-01

Full Text Available In the last two decades, a significant number of innovative sensing systems based on optical fiber sensors have been exploited in the engineering community due to their inherent distinctive advantages such as small size, light weight, immunity to electromagnetic interference (EMI and corrosion, and embedding capability. A lot of optical fiber sensor-based monitoring systems have been developed for continuous measurement and real-time assessment of diversified engineering structures such as bridges, buildings, tunnels, pipelines, wind turbines, railway infrastructure, and geotechnical structures. The purpose of this review article is devoted to presenting a summary of the basic principles of various optical fiber sensors, innovation in sensing and computational methodologies, development of novel optical fiber sensors, and the practical application status of the optical fiber sensing technology in structural health monitoring (SHM of civil infrastructure.

Effectiveness of compressed sensing and transmission in wireless sensor networks for structural health monitoring

Science.gov (United States)

Fujiwara, Takahiro; Uchiito, Haruki; Tokairin, Tomoya; Kawai, Hiroyuki

2017-04-01

Regarding Structural Health Monitoring (SHM) for seismic acceleration, Wireless Sensor Networks (WSN) is a promising tool for low-cost monitoring. Compressed sensing and transmission schemes have been drawing attention to achieve effective data collection in WSN. Especially, SHM systems installing massive nodes of WSN require efficient data transmission due to restricted communications capability. The dominant frequency band of seismic acceleration is occupied within 100 Hz or less. In addition, the response motions on upper floors of a structure are activated at a natural frequency, resulting in induced shaking at the specified narrow band. Focusing on the vibration characteristics of structures, we introduce data compression techniques for seismic acceleration monitoring in order to reduce the amount of transmission data. We carry out a compressed sensing and transmission scheme by band pass filtering for seismic acceleration data. The algorithm executes the discrete Fourier transform for the frequency domain and band path filtering for the compressed transmission. Assuming that the compressed data is transmitted through computer networks, restoration of the data is performed by the inverse Fourier transform in the receiving node. This paper discusses the evaluation of the compressed sensing for seismic acceleration by way of an average error. The results present the average error was 0.06 or less for the horizontal acceleration, in conditions where the acceleration was compressed into 1/32. Especially, the average error on the 4th floor achieved a small error of 0.02. Those results indicate that compressed sensing and transmission technique is effective to reduce the amount of data with maintaining the small average error.

Tradescantia bioassays as monitoring systems for environmental mutagenesis: a review

International Nuclear Information System (INIS)

Rodrigues, G.S.; Ma, T.H.; Pimentel, D.; Weinstein, L.H.

1997-01-01

Since the early studies on the genetic effects of chemical and physical agents, species and clones of Tradescantia have been used as experimental subjects, by virtue of a series of favorable genetic characteristics. Bearing just six pairs (2n = 12) of large, easily observable chromosomes, cells from almost every part of the plant, from the root tips to the developing pollen tube, yield excellent material for cytogenetic studies. As a consequence of the intensive use of Tradescantia in genetic studies, a series of genetic characteristics have been found that offer opportunities for the detection of agents affecting the stability of the genome. At least five such characteristics have been selected as endpoints for the establishment of assays to evaluate mutagenesis. Three of these, root-tip mitosis, pollen-tube, and microspore mitosis are essentially chromosome aberration assays, wherein one observes and evaluates the visible damage in the chromosomes. A fourth, the stamen-hair mutation assay (Trad-SHM), is a point mutation mitotic assay based on the expression of a recessive gene for flower color in heterozygous plants. The fifth assay is a cytogenetic test based on the formation of micronuclei (Trad-MCN) that result from chromosome breakage in the meiotic pollen mother cells. This article examines the characteristics and fundamentals of the Trad-MCN and the Trad-SHM assays and reviews the results obtained to date with these systems in the assessment of environmental mutagenesis. (author)

Cointegration as a data normalization tool for structural health monitoring applications

Science.gov (United States)

Harvey, Dustin Y.; Todd, Michael D.

2012-04-01

The structural health monitoring literature has shown an abundance of features sensitive to various types of damage in laboratory tests. However, robust feature extraction in the presence of varying operational and environmental conditions has proven to be one of the largest obstacles in the development of practical structural health monitoring systems. Cointegration, a technique adapted from the field of econometrics, has recently been introduced to the SHM field as one solution to the data normalization problem. Response measurements and feature histories often show long-run nonstationarity due to fluctuating temperature, load conditions, or other factors that leads to the occurrence of false positives. Cointegration theory allows nonstationary trends common to two or more time series to be modeled and subsequently removed. Thus, the residual retains sensitivity to damage with dependence on operational and environmental variability removed. This study further explores the use of cointegration as a data normalization tool for structural health monitoring applications.

Frequency selective surface based passive wireless sensor for structural health monitoring

International Nuclear Information System (INIS)

Jang, Sang-Dong; Kang, Byung-Woo; Kim, Jaehwan

2013-01-01

Wireless sensor networks or ubiquitous sensor networks are a promising technology giving useful information to people. In particular, the chipless passive wireless sensor is one of the most important developments in wireless sensor technology because it is compact and does not need a battery or chip for the sensor operation. So it has many possibilities for use in various types of sensor system with economical efficiency and robustness in harsh environmental conditions. This sensor uses an electromagnetic resonance frequency or phase angle shift associated with a geometrical change of the sensor tag or an impedance change of the sensor. In this paper, a chipless passive wireless structural health monitoring (SHM) sensor is made using a frequency selective surface (FSS). The cross type FSS is introduced, and its SHM principle is explained. The electromagnetic characteristics of the FSS are simulated in terms of transmission and reflection coefficients using simulation software, and an experimental verification is conducted. The electromagnetic characteristic change of the FSS in the presence of mechanical strain or a structural crack is investigated by means of simulation and experiment. Since large-area structures can be covered by deploying FSS, it is possible to detect the location of any cracks. (paper)

Self-sensing of carbon nanofiber concrete columns subjected to reversed cyclic loading

Science.gov (United States)

Howser, R. N.; Dhonde, H. B.; Mo, Y. L.

2011-08-01

Civil infrastructures are generally a country's most expensive investment, and concrete is the most widely used material in the construction of civil infrastructures. During a structure's service life, concrete ages and deteriorates, leading to substantial loss of structural integrity and potentially resulting in catastrophic disasters such as highway bridge collapses. A solution for preventing such occurrences is the use of structural health monitoring (SHM) technology for concrete structures containing carbon nanofibers (CNF). CNF concrete has many structural benefits. CNF restricts the growth of nanocracks in addition to yielding higher strength and ductility. Additionally, test results indicate a relationship between electrical resistance and concrete strain, which can be well utilized for SHM. A series of reinforced concrete (RC) columns were built and tested under a reversed cyclic loading using CNF as a SHM device. The SHM device detected and assessed the level of damage in the RC columns, providing a real-time health monitoring system for the structure's overall integrity.

Self-sensing of carbon nanofiber concrete columns subjected to reversed cyclic loading

International Nuclear Information System (INIS)

Howser, R N; Dhonde, H B; Mo, Y L

2011-01-01

Civil infrastructures are generally a country's most expensive investment, and concrete is the most widely used material in the construction of civil infrastructures. During a structure's service life, concrete ages and deteriorates, leading to substantial loss of structural integrity and potentially resulting in catastrophic disasters such as highway bridge collapses. A solution for preventing such occurrences is the use of structural health monitoring (SHM) technology for concrete structures containing carbon nanofibers (CNF). CNF concrete has many structural benefits. CNF restricts the growth of nanocracks in addition to yielding higher strength and ductility. Additionally, test results indicate a relationship between electrical resistance and concrete strain, which can be well utilized for SHM. A series of reinforced concrete (RC) columns were built and tested under a reversed cyclic loading using CNF as a SHM device. The SHM device detected and assessed the level of damage in the RC columns, providing a real-time health monitoring system for the structure's overall integrity

Combination of digital signal processing methods towards an improved analysis algorithm for structural health monitoring.

Science.gov (United States)

Pentaris, Fragkiskos P.; Makris, John P.

2013-04-01

In Structural Health Monitoring (SHM) is of great importance to reveal valuable information from the recorded SHM data that could be used to predict or indicate structural fault or damage in a building. In this work a combination of digital signal processing methods, namely FFT along with Wavelet Transform is applied, together with a proposed algorithm to study frequency dispersion, in order to depict non-linear characteristics of SHM data collected in two university buildings under natural or anthropogenic excitation. The selected buildings are of great importance from civil protection point of view, as there are the premises of a public higher education institute, undergoing high use, stress, visit from academic staff and students. The SHM data are collected from two neighboring buildings that have different age (4 and 18 years old respectively). Proposed digital signal processing methods are applied to the data, presenting a comparison of the structural behavior of both buildings in response to seismic activity, weather conditions and man-made activity. Acknowledgments This work was supported in part by the Archimedes III Program of the Ministry of Education of Greece, through the Operational Program "Educational and Lifelong Learning", in the framework of the project entitled «Interdisciplinary Multi-Scale Research of Earthquake Physics and Seismotectonics at the front of the Hellenic Arc (IMPACT-ARC) » and is co-financed by the European Union (European Social Fund) and Greek National Fund.

Time-Frequency Methods for Structural Health Monitoring

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Alexander L. Pyayt

2014-03-01

Full Text Available Detection of early warning signals for the imminent failure of large and complex engineered structures is a daunting challenge with many open research questions. In this paper we report on novel ways to perform Structural Health Monitoring (SHM of flood protection systems (levees, earthen dikes and concrete dams using sensor data. We present a robust data-driven anomaly detection method that combines time-frequency feature extraction, using wavelet analysis and phase shift, with one-sided classification techniques to identify the onset of failure anomalies in real-time sensor measurements. The methodology has been successfully tested at three operational levees. We detected a dam leakage in the retaining dam (Germany and “strange” behaviour of sensors installed in a Boston levee (UK and a Rhine levee (Germany.

Intelligent Hardware-Enabled Sensor and Software Safety and Health Management for Autonomous UAS

Science.gov (United States)

Rozier, Kristin Y.; Schumann, Johann; Ippolito, Corey

2015-01-01

Unmanned Aerial Systems (UAS) can only be deployed if they can effectively complete their mission and respond to failures and uncertain environmental conditions while maintaining safety with respect to other aircraft as well as humans and property on the ground. We propose to design a real-time, onboard system health management (SHM) capability to continuously monitor essential system components such as sensors, software, and hardware systems for detection and diagnosis of failures and violations of safety or performance rules during the ight of a UAS. Our approach to SHM is three-pronged, providing: (1) real-time monitoring of sensor and software signals; (2) signal analysis, preprocessing, and advanced on-the- y temporal and Bayesian probabilistic fault diagnosis; (3) an unobtrusive, lightweight, read-only, low-power hardware realization using Field Programmable Gate Arrays (FPGAs) in order to avoid overburdening limited computing resources or costly re-certi cation of ight software due to instrumentation. No currently available SHM capabilities (or combinations of currently existing SHM capabilities) come anywhere close to satisfying these three criteria yet NASA will require such intelligent, hardwareenabled sensor and software safety and health management for introducing autonomous UAS into the National Airspace System (NAS). We propose a novel approach of creating modular building blocks for combining responsive runtime monitoring of temporal logic system safety requirements with model-based diagnosis and Bayesian network-based probabilistic analysis. Our proposed research program includes both developing this novel approach and demonstrating its capabilities using the NASA Swift UAS as a demonstration platform.

ATCA Shelf Manager EPICS device support for ITER CODAC Core System

Energy Technology Data Exchange (ETDEWEB)

Santos, Bruno, E-mail: bsantos@ipfn.ist.utl.pt [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal); Carvalho, Paulo F.; Rodrigues, A.P.; Carvalho, Bernardo B.; Sousa, Jorge; Batista, António J.N.; Correia, Miguel; Combo, Álvaro M.; Cruz, Nuno [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal); Correia, Carlos M.B.A. [Centro de Instrumentação, Departamento de Física, Universidade de Coimbra, 3004-516 Coimbra (Portugal); Gonçalves, Bruno [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal)

2015-10-15

Highlights: • This architecture targets the health management integration into the NDS. • The developed solution supports the ShM redundancy features, specified by ATCA. • The average RTT was around 59 ms and in 99.9% of the cases was less than 130 ms. • Without losing any update cycle, can monitor a system shelf with approximately 400 sensors. • This solution enables the user to configure the entire system in DB files and st.cmd. - Abstract: The ITER CODAC Core System (CCS) is responsible for plant Instrumentation and Control (I&C) supervising and monitoring. This system uses the Enhanced Physics and Industrial Control System (EPICS) Channel Access (CA) protocol as the interface with the Plant Operation Network (PON). This paper presents a generic EPICS device support developed for the integration of the ATCA Shelf Manager (ShM) into the ITER CCS, providing scalability and easy configuration. The device support uses the available HTTP interface on Shelf Manager in the communication layer. Both HTTP server and sensors/actuators definitions can be configured using the EPICS database file and the Input/Output Controller (IOC) initialization file. A proposal based on this device is also presented, targeting the Nominal Device Support (NDS) for health management. The EPICS device support running in an IOC provides Process Variables (PV) to the PON network with the system information and these PVs can be used by all CA clients, such as EPICS user interface clients, alarm systems and archive systems. Operation with redundant ATCA ShMs and device support scalability tests were performed and the results are presented.

A Methodological Review of Piezoelectric Based Acoustic Wave Generation and Detection Techniques for Structural Health Monitoring

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Zhigang Sun

2013-01-01

Full Text Available Piezoelectric transducers have a long history of applications in nondestructive evaluation of material and structure integrity owing to their ability of transforming mechanical energy to electrical energy and vice versa. As condition based maintenance has emerged as a valuable approach to enhancing continued aircraft airworthiness while reducing the life cycle cost, its enabling structural health monitoring (SHM technologies capable of providing on-demand diagnosis of the structure without interrupting the aircraft operation are attracting increasing R&D efforts. Piezoelectric transducers play an essential role in these endeavors. This paper is set forth to review a variety of ingenious ways in which piezoelectric transducers are used in today’s SHM technologies as a means of generation and/or detection of diagnostic acoustic waves.

Electromagnetic-based force sensor for Structural Health Monitoring(SHM)

International Nuclear Information System (INIS)

Choi, Man Yong; Park, Hae Won; Park, Jeong Hak; Sam, R.

2002-01-01

The demand for maintenance of structural health and safety to acceptable standards poses challenges for research and development of effective technologies for monitoring and measurement of parameters governing safety and health of structures. In this work, an electromagnetic based sensor has been investigated and developed for measuring force in pre-stressed steel cables and tendons. The change in magnetic permeability of a material caused by mechanical stress is exploited to measure force in the material. The sensor consists of a pair of sensing coils and a pair of reference coils. The sensing coils are wound around a stressed material while the reference pair are wound on a dummy specimen of same material as that under stress. When sensing and reference primary coils are excited by same current simultaneously, both the stressed and dummy materials are equally magnetized by the magnetic field generated by the current, and voltage is induced in the sensing and reference secondary coils. The induced voltage in each secondary coil is dependent on a number of factors including the magnetic permeability of its core which is a function of the core magnetizing current, temperature and stress/load. By suitably arranging the sensing and reference coils electro-magnetically, the effects of temperature and magnetizing current on the permeability of a stressed material can be eliminated in the output voltage of the sensor. The output voltage is a function of only the mechanical load in the stressed material, and can be calibrated for determination of force in pre-stressed materials

Goal-Function Tree Modeling for Systems Engineering and Fault Management

Science.gov (United States)

Johnson, Stephen B.; Breckenridge, Jonathan T.

2013-01-01

The draft NASA Fault Management (FM) Handbook (2012) states that Fault Management (FM) is a "part of systems engineering", and that it "demands a system-level perspective" (NASAHDBK- 1002, 7). What, exactly, is the relationship between systems engineering and FM? To NASA, systems engineering (SE) is "the art and science of developing an operable system capable of meeting requirements within often opposed constraints" (NASA/SP-2007-6105, 3). Systems engineering starts with the elucidation and development of requirements, which set the goals that the system is to achieve. To achieve these goals, the systems engineer typically defines functions, and the functions in turn are the basis for design trades to determine the best means to perform the functions. System Health Management (SHM), by contrast, defines "the capabilities of a system that preserve the system's ability to function as intended" (Johnson et al., 2011, 3). Fault Management, in turn, is the operational subset of SHM, which detects current or future failures, and takes operational measures to prevent or respond to these failures. Failure, in turn, is the "unacceptable performance of intended function." (Johnson 2011, 605) Thus the relationship of SE to FM is that SE defines the functions and the design to perform those functions to meet system goals and requirements, while FM detects the inability to perform those functions and takes action. SHM and FM are in essence "the dark side" of SE. For every function to be performed (SE), there is the possibility that it is not successfully performed (SHM); FM defines the means to operationally detect and respond to this lack of success. We can also describe this in terms of goals: for every goal to be achieved, there is the possibility that it is not achieved; FM defines the means to operationally detect and respond to this inability to achieve the goal. This brief description of relationships between SE, SHM, and FM provide hints to a modeling approach to

Novel Monitoring Techniques for Characterizing Frictional Interfaces in the Laboratory

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Paul A. Selvadurai

2015-04-01

Full Text Available A pressure-sensitive film was used to characterize the asperity contacts along a polymethyl methacrylate (PMMA interface in the laboratory. The film has structural health monitoring (SHM applications for flanges and other precision fittings and train rail condition monitoring. To calibrate the film, simple spherical indentation tests were performed and validated against a finite element model (FEM to compare normal stress profiles. Experimental measurements of the normal stress profiles were within −7.7% to 6.6% of the numerical calculations between 12 and 50 MPa asperity normal stress. The film also possessed the capability of quantifying surface roughness, an important parameter when examining wear and attrition in SHM applications. A high definition video camera supplied data for photometric analysis (i.e., the measure of visible light of asperities along the PMMA-PMMA interface in a direct shear configuration, taking advantage of the transparent nature of the sample material. Normal stress over individual asperities, calculated with the pressure-sensitive film, was compared to the light intensity transmitted through the interface. We found that the luminous intensity transmitted through individual asperities linearly increased 0.05643 ± 0.0012 candelas for an increase of 1 MPa in normal stress between normal stresses ranging from 23 to 33 MPa.

Optimum wireless sensor deployment scheme for structural health monitoring: a simulation study

International Nuclear Information System (INIS)

Liu, Chengyin; Fang, Kun; Teng, Jun

2015-01-01

With the rapid advancements in smart sensing technology and wireless communication technology, the wireless sensor network (WSN) offers an alternative solution to structural health monitoring (SHM). In WSNs, dense deployment of wireless nodes aids the identification of structural dynamic characteristics, while data transmission is a significant issue since wireless channels typically have a lower bandwidth and a limited power supply. This paper provides a wireless sensor deployment optimization scheme for SHM, in terms of both energy consumption and modal identification accuracy. A spherical energy model is established to formulate the energy consumption within a WSN. The optimal number of sensors and their locations are obtained through solving a multi-objective function with weighting factors on energy consumption and modal identification accuracy using a genetic algorithm (GA). Simulation and comparison results with traditional sensor deployment methods demonstrate the efficiency of the proposed optimization scheme. (paper)

Synthesizing spatiotemporally sparse smartphone sensor data for bridge modal identification

Science.gov (United States)

Ozer, Ekin; Feng, Maria Q.

2016-08-01

Smartphones as vibration measurement instruments form a large-scale, citizen-induced, and mobile wireless sensor network (WSN) for system identification and structural health monitoring (SHM) applications. Crowdsourcing-based SHM is possible with a decentralized system granting citizens with operational responsibility and control. Yet, citizen initiatives introduce device mobility, drastically changing SHM results due to uncertainties in the time and the space domains. This paper proposes a modal identification strategy that fuses spatiotemporally sparse SHM data collected by smartphone-based WSNs. Multichannel data sampled with the time and the space independence is used to compose the modal identification parameters such as frequencies and mode shapes. Structural response time history can be gathered by smartphone accelerometers and converted into Fourier spectra by the processor units. Timestamp, data length, energy to power conversion address temporal variation, whereas spatial uncertainties are reduced by geolocation services or determining node identity via QR code labels. Then, parameters collected from each distributed network component can be extended to global behavior to deduce modal parameters without the need of a centralized and synchronous data acquisition system. The proposed method is tested on a pedestrian bridge and compared with a conventional reference monitoring system. The results show that the spatiotemporally sparse mobile WSN data can be used to infer modal parameters despite non-overlapping sensor operation schedule.

A self-diagnostic adhesive for monitoring bonded joints in aerospace structures

Science.gov (United States)

Zhuang, Yitao; Li, Yu-hung; Kopsaftopoulos, Fotis; Chang, Fu-Kuo

2016-04-01

Bondline integrity is still one of the most critical concerns in the design of aircraft structures up to date. Due to the lack of confidence on the integrity of the bondline both during fabrication and service, the industry standards and regulations still require assembling the composite using conventional fasteners. Furthermore, current state-of-the-art non-destructive evaluation (NDE) and structural health monitoring (SHM) techniques are incapable of offering mature solutions on the issue of bondline integrity monitoring. Therefore, the objective of this work is the development of an intelligent adhesive film with integrated micro-sensors for monitoring the integrity of the bondline interface. The proposed method makes use of an electromechanical-impedance (EMI) based method, which is a rapidly evolving approach within the SHM family. Furthermore, an innovative screen-printing technique to fabricate piezoelectric ceramic sensors with minimal thickness has been developed at Stanford. The approach presented in this study is based on the use of (i) micro screen-printed piezoelectric sensors integrated into adhesive leaving a minimal footprint on the material, (ii) numerical and analytical modeling of the EMI spectrum of the adhesive bondline, (iii) novel diagnostic algorithms for monitoring the bondline integrity based on advanced signal processing techniques, and (iv) the experimental assessment via prototype adhesively bonded structures in static (varying loads) and dynamic (fatigue) environments. The proposed method will provide a huge confidence on the use of bonded joints for aerospace structures and lead to a paradigm change in their design by enabling enormous weight savings while maximizing the economic and performance efficiency.

Yonjung High-Speed Railway Bridge Assessment Using Output-Only Structural Health Monitoring Measurements under Train Speed Changing

Directory of Open Access Journals (Sweden)

Mosbeh R. Kaloop

2016-01-01

Full Text Available Yonjung Bridge is a hybrid multispan bridge that is designed to transport high-speed trains (HEMU-430X with maximum operating speed of 430 km/h. The bridge consists of simply supported prestressed concrete (PSC and composite steel girders to carry double railway tracks. The structural health monitoring system (SHM is designed and installed to investigate and assess the performance of the bridge in terms of acceleration and deformation measurements under different speeds of the passing train. The SHM measurements are investigated in both time and frequency domains; in addition, several identification models are examined to assess the performance of the bridge. The drawn conclusions show that the maximum deflection and acceleration of the bridge are within the design limits that are specified by the Korean and European codes. The parameters evaluation of the model identification depicts the quasistatic and dynamic deformations of PSC and steel girders to be different and less correlated when higher speeds of the passing trains are considered. Finally, the variation of the frequency content of the dynamic deformations of the girders is negligible when high speeds are considered.

Structural health monitoring of the Gröndals Bridge in Sweden: the behaviour of CFRP strengthening in cold temperature

Science.gov (United States)

Hejll, Arvid; Täljsten, Björn; Carolin, Anders

2006-03-01

To obtain a better knowledge of existing structures behaviour monitoring can be used. The use of monitoring in bridge structures by the use of instruments to assess the integrity of structures is not new and there are reports from structures tested as early as in the 19th century according to ISIS Canada1 However, the term SHM (Structural Health Monitoring) is relatively new to civil engineering and the driving force to implement SHM comes from recognising the limitations of conventional visual inspections and evaluations using conservative codes of practice. The possibilities to monitor existing structures with help of the rapidly evolving Information Technology are to day carried out. The objective of SHM is to monitor the in-situ behaviour of a structure accurately and efficiently, to assess its performance under various service conditions, to detect damage or deterioration, and to determine the health or condition of the structure1. In Sweden strengthening and periodic monitoring of a large freivorbau bridge (pre-stresed concrete box girder bridge) has been carried out, the Gröndals Bridge. The bridge is located in Stockholm and is approximately 400 m in length with a free span of 120 m. It was opened to tram traffic in year 2000. Just after opening cracks were noticed in the webs, these cracks have then increased, the size of the largest cracks exceeded 0.5 mm, and at the end of year 2001 the bridge was temporarily strengthened. This was carried out with externally placed prestressed steel stays. The reason for cracking is quite clear but the responsibility is still debated. Nevertheless, it was evidently that the bridge needed to be strengthened. The strengthening methods used were CFRP plates in the Service Limit State (SLS) and prestressed dywidag stays in the Ultimate Limit State (ULS). The strengthening was carried out during year 2002. At the same time monitoring of the bridge commenced, using LVDT crack gauges as well as optical fibre sensors. This

Wireless sensor placement for structural monitoring using information-fusing firefly algorithm

Science.gov (United States)

Zhou, Guang-Dong; Yi, Ting-Hua; Xie, Mei-Xi; Li, Hong-Nan

2017-10-01

Wireless sensor networks (WSNs) are promising technology in structural health monitoring (SHM) applications for their low cost and high efficiency. The limited wireless sensors and restricted power resources in WSNs highlight the significance of optimal wireless sensor placement (OWSP) during designing SHM systems to enable the most useful information to be captured and to achieve the longest network lifetime. This paper presents a holistic approach, including an optimization criterion and a solution algorithm, for optimally deploying self-organizing multi-hop WSNs on large-scale structures. The combination of information effectiveness represented by the modal independence and the network performance specified by the network connectivity and network lifetime is first formulated to evaluate the performance of wireless sensor configurations. Then, an information-fusing firefly algorithm (IFFA) is developed to solve the OWSP problem. The step sizes drawn from a Lévy distribution are adopted to drive fireflies toward brighter individuals. Following the movement with Lévy flights, information about the contributions of wireless sensors to the objective function as carried by the fireflies is fused and applied to move inferior wireless sensors to better locations. The reliability of the proposed approach is verified via a numerical example on a long-span suspension bridge. The results demonstrate that the evaluation criterion provides a good performance metric of wireless sensor configurations, and the IFFA outperforms the simple discrete firefly algorithm.

A novel HVSR approach on structural heath monitoring for structural vulnerability assesement

Science.gov (United States)

Pentaris, Fragkiskos P.; Papadopoulos, Ilias

2014-05-01

of Education of Greece and the European Union in the framework of the project entitled «Interdisciplinary Multi-Scale Research of Earthquake Physics and Seismotectonics at the front of the Hellenic Arc (IMPACT-ARC) ». References [1] F. P. Pentaris, J. Stonham, and J. P. Makris, "A review of the state-of-the-art of wireless SHM systems and an experimental set-up towards an improved design," presented at the EUROCON, 2013 IEEE, Zagreb, 2013. [2] R. Ditommaso, M. Mucciarelli, S. Parolai, and M. Picozzi, "Monitoring the structural dynamic response of a masonry tower: Comparing classical and time-frequency analyses," Bulletin of Earthquake Engineering, vol. 10, pp. 1221-1235, 2012. [3] Sungkono, D. D. Warnana, Triwulan, and W. Utama, "Evaluation of Buildings Strength from Microtremor Analyses " International Journal of Civil & Environmental Engineering IJCEE-IJENS, vol. 11, 2011. [4] L.-L. Hong and W.-L. Hwang, "Empirical formula for fundamental vibration periods of reinforced concrete buildings in Taiwan," Earthquake Engineering & Structural Dynamics, vol. 29, pp. 327-337, 2000.

A real-time deflection monitoring system for wind turbine blades using a built-in laser displacement sensor

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyeong-Cheol; Giri, Paritosh; Lee, Jung-Ryul [Korea Chonbuk National Univ., Jeonbuk (Korea, Republic of). Dept. of Aerospace Engineering and LANL-CBNU Engineering Inst.

2012-07-01

Renewable energy is considered a good alternative to deal with the issues related to fossil fuel and environmental pollution. Wind energy as one of such renewable energy alternatives has seen a substantial growth. With commercially viable global wind power potential, wind energy penetration is further expected to rise, and so will the related problems. One of the issues is the collision of wind blade and tower during operation. To improve safety during operation, to minimize the risk of sudden failure or total breakdown, and to ensure reliable power generation and reduce wind turbine life cycle costs, a structural health monitoring (SHM) technology is required. This study proposes a single laser displacement sensor (LDS) system, where all of the rotating blades could be evaluated effectively. The system is cost-effective as well, as the system costs only a mere thousand dollars. If the blade bolt loosening occurs, it causes deflection in the affected blade. In a similar manner, nacelle tilt or mass loss damage in the blade will result in change of blade's position and the proposed system can identify such problems with ease. With increased demand of energy, the sizes of wind blades are getting bigger and bigger due to which people are installing wind turbines very high above the ground level or offshore. It is impractical to monitor the deflection through wired connection in these cases and hence can be replaced by a wireless solution. This wireless solution is achieved using Zigbee technology which operates in the industrial, scientific and medical (ISM) radio bands, typically 2.4 GHz, 915 MHz and 868 MHz. The output from the LDS is fed to the microcontroller which acts as an analog to digital converter which in turn is connected to the Zigbee transceiver module, which transmits the data. At the other end, the Zigbee reads the data and displays on the PC from where user can monitor the condition of wind blades. (orig.)

Identifying Time Periods of Minimal Thermal Gradient for Temperature-Driven Structural Health Monitoring

Directory of Open Access Journals (Sweden)

John Reilly

2018-03-01

Full Text Available Temperature changes play a large role in the day to day structural behavior of structures, but a smaller direct role in most contemporary Structural Health Monitoring (SHM analyses. Temperature-Driven SHM will consider temperature as the principal driving force in SHM, relating a measurable input temperature to measurable output generalized strain (strain, curvature, etc. and generalized displacement (deflection, rotation, etc. to create three-dimensional signatures descriptive of the structural behavior. Identifying time periods of minimal thermal gradient provides the foundation for the formulation of the temperature–deformation–displacement model. Thermal gradients in a structure can cause curvature in multiple directions, as well as non-linear strain and stress distributions within the cross-sections, which significantly complicates data analysis and interpretation, distorts the signatures, and may lead to unreliable conclusions regarding structural behavior and condition. These adverse effects can be minimized if the signatures are evaluated at times when thermal gradients in the structure are minimal. This paper proposes two classes of methods based on the following two metrics: (i the range of raw temperatures on the structure, and (ii the distribution of the local thermal gradients, for identifying time periods of minimal thermal gradient on a structure with the ability to vary the tolerance of acceptable thermal gradients. The methods are tested and validated with data collected from the Streicker Bridge on campus at Princeton University.

Identifying Time Periods of Minimal Thermal Gradient for Temperature-Driven Structural Health Monitoring.

Science.gov (United States)

Reilly, John; Glisic, Branko

2018-03-01

Temperature changes play a large role in the day to day structural behavior of structures, but a smaller direct role in most contemporary Structural Health Monitoring (SHM) analyses. Temperature-Driven SHM will consider temperature as the principal driving force in SHM, relating a measurable input temperature to measurable output generalized strain (strain, curvature, etc.) and generalized displacement (deflection, rotation, etc.) to create three-dimensional signatures descriptive of the structural behavior. Identifying time periods of minimal thermal gradient provides the foundation for the formulation of the temperature-deformation-displacement model. Thermal gradients in a structure can cause curvature in multiple directions, as well as non-linear strain and stress distributions within the cross-sections, which significantly complicates data analysis and interpretation, distorts the signatures, and may lead to unreliable conclusions regarding structural behavior and condition. These adverse effects can be minimized if the signatures are evaluated at times when thermal gradients in the structure are minimal. This paper proposes two classes of methods based on the following two metrics: (i) the range of raw temperatures on the structure, and (ii) the distribution of the local thermal gradients, for identifying time periods of minimal thermal gradient on a structure with the ability to vary the tolerance of acceptable thermal gradients. The methods are tested and validated with data collected from the Streicker Bridge on campus at Princeton University.

Nominal Device Support for ATCA Shelf Manager

Energy Technology Data Exchange (ETDEWEB)

Santos, Bruno; Carvalho, Paulo F.; Rodrigues, A.P.; Carvalho, Bernardo B.; Sousa, Jorge; Batista, Antonio J.N.; Combo, Alvaro M.; Cruz, Nuno; Correia, Carlos M.B.A.; Goncalves, Bruno [Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal); Correia, Miguel [Centro de Instrumentacao, Departamento de Fisica, Universidade de Coimbra, 3004-516 Coimbra (Portugal)

2015-07-01

The ATCA standard specifies a mandatory Shelf Manager (ShM) unit which is a key element for the system operation. It includes the Intelligent Platform Management Controller (IPMC) which monitors the system health, retrieves inventory information and controls the Field Replaceable Units (FRUs). These elements enable the intelligent health monitoring, providing high-availability and safety operation, ensuring the correct system operation. For critical systems like ones of tokamak ITER these features are mandatory to support the long pulse operation. The Nominal Device Support (NDS) was designed and developed for the ITER CODAC Core System (CCS), which will be the responsible for plant Instrumentation and Control (I and C), supervising and monitoring on ITER. It generalizes the Enhanced Physics and Industrial Control System (EPICS) device support interface for Data Acquisition (DAQ) and timing devices. However the support for health management features and ATCA ShM are not yet provided. This paper presents the implementation and test of a NDS for the ATCA ShM, using the ITER Fast Plant System Controller (FPSC) prototype environment. This prototype is fully compatible with the ITER CCS and uses the EPICS Channel Access (CA) protocol as the interface with the Plant Operation Network (PON). The implemented solution running in an EPICS Input / Output Controller (IOC) provides Process Variables (PV) to the PON network with the system information. These PVs can be used for control and monitoring by all CA clients, such as EPICS user interface clients and alarm systems. The results are presented, demonstrating the fully integration and the usability of this solution. (authors)

Passively-Coded Embedded Wideband Microwave Sensors for Material Characterization and Structural Health Monitoring (SHM)

Data.gov (United States)

National Aeronautics and Space Administration — Materials and structures are constantly subject to fatigue and degradation, and monitoring and maintaining civil, space, and aerospace infrastructure is an ongoing...

FE-ANN based modeling of 3D simple reinforced concrete girders for objective structural health evaluation.

Science.gov (United States)

2017-06-01

The structural deterioration of aging infrastructure systems and the costs of repairing these systems is an increasingly important issue worldwide. Structural health monitoring (SHM), most commonly visual inspection and condition rating, has proven t...

A Structural Model Decomposition Framework for Systems Health Management

Science.gov (United States)

Roychoudhury, Indranil; Daigle, Matthew J.; Bregon, Anibal; Pulido, Belamino

2013-01-01

Systems health management (SHM) is an important set of technologies aimed at increasing system safety and reliability by detecting, isolating, and identifying faults; and predicting when the system reaches end of life (EOL), so that appropriate fault mitigation and recovery actions can be taken. Model-based SHM approaches typically make use of global, monolithic system models for online analysis, which results in a loss of scalability and efficiency for large-scale systems. Improvement in scalability and efficiency can be achieved by decomposing the system model into smaller local submodels and operating on these submodels instead. In this paper, the global system model is analyzed offline and structurally decomposed into local submodels. We define a common model decomposition framework for extracting submodels from the global model. This framework is then used to develop algorithms for solving model decomposition problems for the design of three separate SHM technologies, namely, estimation (which is useful for fault detection and identification), fault isolation, and EOL prediction. We solve these model decomposition problems using a three-tank system as a case study.

A structural model decomposition framework for systems health management

Science.gov (United States)

Roychoudhury, I.; Daigle, M.; Bregon, A.; Pulido, B.

Systems health management (SHM) is an important set of technologies aimed at increasing system safety and reliability by detecting, isolating, and identifying faults; and predicting when the system reaches end of life (EOL), so that appropriate fault mitigation and recovery actions can be taken. Model-based SHM approaches typically make use of global, monolithic system models for online analysis, which results in a loss of scalability and efficiency for large-scale systems. Improvement in scalability and efficiency can be achieved by decomposing the system model into smaller local submodels and operating on these submodels instead. In this paper, the global system model is analyzed offline and structurally decomposed into local submodels. We define a common model decomposition framework for extracting submodels from the global model. This framework is then used to develop algorithms for solving model decomposition problems for the design of three separate SHM technologies, namely, estimation (which is useful for fault detection and identification), fault isolation, and EOL prediction. We solve these model decomposition problems using a three-tank system as a case study.

Application of the spherical harmonic gravity model in high precision inertial navigation systems

International Nuclear Information System (INIS)

Wang, Jing; Yang, Gongliu; Zhou, Xiao; Li, Xiangyun

2016-01-01

The spherical harmonic gravity model (SHM) may, in general, be considered as a suitable alternative to the normal gravity model (NGM), because it represents the Earth’s gravitational field more accurately. However, the high-resolution SHM has never been used in current inertial navigation systems (INSs) due to its extremely complex expression. In this paper, the feasibility and accuracy of a truncated SHM are discussed for application in a real-time free-INS with a precision demand better than 0.8 nm h −1 . In particular, the time and space complexity are analyzed mathematically to verify the feasibility of the SHM. Also, a test on a typical navigation computer shows a storable range of cut-off degrees. To further evaluate the appropriate degree and accuracy of the truncated SHM, analyses of covariance and truncation error are proposed. Finally, a SHM of degree 12 is demonstrated to be the appropriate model for routine INSs in the precision range of 0.4–0.75 nm h −1 . Flight simulations and road tests show its outstanding performance over the traditional NGM. (paper)

Integration of bridge damage detection concepts and components, volume II : acceleration-based damage detection.

Science.gov (United States)

2013-10-01

In this work, a previously developed structural health monitoring (SHM) system was advanced toward a ready-for-implementation system. Improvements were made with respect to automated data reduction/analysis, data acquisition hardware, sensor types, a...

Big data and high-performance analytics in structural health monitoring for bridge management

Science.gov (United States)

Alampalli, Sharada; Alampalli, Sandeep; Ettouney, Mohammed

2016-04-01

Structural Health Monitoring (SHM) can be a vital tool for effective bridge management. Combining large data sets from multiple sources to create a data-driven decision-making framework is crucial for the success of SHM. This paper presents a big data analytics framework that combines multiple data sets correlated with functional relatedness to convert data into actionable information that empowers risk-based decision-making. The integrated data environment incorporates near real-time streams of semi-structured data from remote sensors, historical visual inspection data, and observations from structural analysis models to monitor, assess, and manage risks associated with the aging bridge inventories. Accelerated processing of dataset is made possible by four technologies: cloud computing, relational database processing, support from NOSQL database, and in-memory analytics. The framework is being validated on a railroad corridor that can be subjected to multiple hazards. The framework enables to compute reliability indices for critical bridge components and individual bridge spans. In addition, framework includes a risk-based decision-making process that enumerate costs and consequences of poor bridge performance at span- and network-levels when rail networks are exposed to natural hazard events such as floods and earthquakes. Big data and high-performance analytics enable insights to assist bridge owners to address problems faster.

Structural health monitoring of a railway truss bridge using vibration-based and ultrasonic methods

Science.gov (United States)

Kołakowski, Przemysław; Szelążek, Jacek; Sekuła, Krzysztof; Świercz, Andrzej; Mizerski, Krzysztof; Gutkiewicz, Piotr

2011-03-01

This paper presents results of in situ investigation of a railway truss bridge in the context of structural health monitoring (SHM). Three experimental methods are examined. Dynamic responses of the bridge recorded by strain gauges are confronted with alternative ways of acquisition using piezoelectric patch sensors and ultrasonic probeheads. All types of sensors produce similar output. Also the corresponding responses of the numerical model of the bridge match experimental data.

Structural health monitoring of a railway truss bridge using vibration-based and ultrasonic methods

International Nuclear Information System (INIS)

Kołakowski, Przemysław; Sekuła, Krzysztof; Szelążek, Jacek; Świercz, Andrzej; Mizerski, Krzysztof; Gutkiewicz, Piotr

2011-01-01

This paper presents results of in situ investigation of a railway truss bridge in the context of structural health monitoring (SHM). Three experimental methods are examined. Dynamic responses of the bridge recorded by strain gauges are confronted with alternative ways of acquisition using piezoelectric patch sensors and ultrasonic probeheads. All types of sensors produce similar output. Also the corresponding responses of the numerical model of the bridge match experimental data

Safety system status monitoring

International Nuclear Information System (INIS)

Lewis, J.R.; Morgenstern, M.H.; Rideout, T.H.; Cowley, P.J.

1984-03-01

The Pacific Northwest Laboratory has studied the safety aspects of monitoring the preoperational status of safety systems in nuclear power plants. The goals of the study were to assess for the NRC the effectiveness of current monitoring systems and procedures, to develop near-term guidelines for reducing human errors associated with monitoring safety system status, and to recommend a regulatory position on this issue. A review of safety system status monitoring practices indicated that current systems and procedures do not adequately aid control room operators in monitoring safety system status. This is true even of some systems and procedures installed to meet existing regulatory guidelines (Regulatory Guide 1.47). In consequence, this report suggests acceptance criteria for meeting the functional requirements of an adequate system for monitoring safety system status. Also suggested are near-term guidelines that could reduce the likelihood of human errors in specific, high-priority status monitoring tasks. It is recommended that (1) Regulatory Guide 1.47 be revised to address these acceptance criteria, and (2) the revised Regulatory Guide 1.47 be applied to all plants, including those built since the issuance of the original Regulatory Guide

Safety system status monitoring

Energy Technology Data Exchange (ETDEWEB)

Lewis, J.R.; Morgenstern, M.H.; Rideout, T.H.; Cowley, P.J.

1984-03-01

The Pacific Northwest Laboratory has studied the safety aspects of monitoring the preoperational status of safety systems in nuclear power plants. The goals of the study were to assess for the NRC the effectiveness of current monitoring systems and procedures, to develop near-term guidelines for reducing human errors associated with monitoring safety system status, and to recommend a regulatory position on this issue. A review of safety system status monitoring practices indicated that current systems and procedures do not adequately aid control room operators in monitoring safety system status. This is true even of some systems and procedures installed to meet existing regulatory guidelines (Regulatory Guide 1.47). In consequence, this report suggests acceptance criteria for meeting the functional requirements of an adequate system for monitoring safety system status. Also suggested are near-term guidelines that could reduce the likelihood of human errors in specific, high-priority status monitoring tasks. It is recommended that (1) Regulatory Guide 1.47 be revised to address these acceptance criteria, and (2) the revised Regulatory Guide 1.47 be applied to all plants, including those built since the issuance of the original Regulatory Guide.

An autonomous strain-based Structural Monitoring Framework for Life-Cycle Analysis of a Novel Structure

Directory of Open Access Journals (Sweden)

Yunus Emre Harmanci

2016-07-01

Full Text Available In recent years, developed societies have largely adopted smart systems operating on the basis of information extracted from data. For infrastructure systems as well, Structural Health Monitoring (SHM has long advocated a data-driven scheme for facilitating the operation and maintenance of infrastructure. In materializing such a goal, this paper demonstrates the procedures and outcomes of a SHM framework employed on an unconventional structure, namely the recently built Kaeng Krachan Elephant Shelter at the Zurich Zoo, relying on a deployed set of Fiber Bragg Grating (FBG strain sensors. The structure comprises an 80 meter span free-form timber-composite cupola, carried by a post-tensioned reinforced concrete (RC ring. FBG strain sensors are embedded into the ring in close vicinity to critical regions, selected in collaboration with the design engineers. The continuously acquired strain data is then exploited for extraction of performance indicators, relying on implementation of output-only identification methodologies. To this end, a non-parametric and a parametric output-only method, namely a Principal Component Analysis (PCA scheme versus a Vector AutoRegressive (VAR model, are employed and compared. Pre-conditioning of the predictive model is performed on the healthy, or undamaged, state of the structure, and the misfit between model predictions and subsequent measurements is exploited as a damage precursor. The VAR scheme proves in this case a more robust representation of the measured strains, when compared against PCA, as a result of its inherent feature of memory.

Active vibration-based SHM system: demonstration on an operating Vestas V27 wind turbine

DEFF Research Database (Denmark)

Tcherniak, Dmitri; Mølgaard, Lasse Lohilahti

2016-01-01

with the system and a 3.5 month monitoring campaign was conducted while the turbine was operating normally. During the campaign, a defect – a trailing edge opening – was artificially introduced into the blade and its size was gradually increased from the original 15 cm to 45 cm. Using an unsupervised learning......This study presents a system that is able to detect defects like cracks, leading/trailing edge opening or delamination of at least 15 cm size, remotely, without stopping the wind turbine. The system is vibration-based: mechanical energy is artificially introduced by means of an electromechanical......-to-noise ratio. At the same time, the corresponding wavelength is short enough to deliver required damage detection resolution and long enough to be able to propagate the entire blade length. The paper demonstrates the system on a 225 kW Vesta s V27 wind turbine. One blade of the wind turbine was equipped...

Finite element modeling to determine thermal residual strain distribution of bonded composite repairs for structural health monitoring design

Science.gov (United States)

Baker, Wayne; Jones, Rhys; Davis, Claire; Galea, Stephen C.

2002-11-01

The economic implication of fleet upgrades, particularly in Australia with military aircraft such as the F-111 and F/A-18, has led to an increasing reliance on composite repair technology to address fatigue and corrosion-affected aircraft components. The increasing use of such repairs has led to a research effort to develop various in-situ health monitoring systems that may be incorporated with a repair. This paper reports on the development of a theoretical methodology that uses finite element analysis (FEA) to model the strain profiles which optical sensors, on or within the patch, will be exposed to under various operational scenarios, including load and disbond. Numerical techniques are then used to predict the fibre Bragg grating (FBG) reflections which occur with these strain profiles. The quality of these reflection are a key consideration when designing FBG based structural health monitoring (SHM) systems. This information can be used to optimise the location of both surface mounted, and embedded sensors, and determine feasibility of SHM system design. Research was conducted into the thermal residual strain (TRS) within the patch. A finite element study revealed the presence of significant thermal residual strain gradients along the surface of the tapered region of the patch. As Bragg gratings are particularly sensitive to strain gradients, (producing a result similar to a chirped grating) the strain gradient on the composite at potential sensor locations both under load, and in the event of disbond was considered. A sufficiently high gradient leads to an altered Bragg reflection. These spurious reflections need to be considered, and theoretically obtained reflections can provide information to allow for load scenarios where the Bragg shift is not a smooth, well defined peak. It can also be shown that embedded fibres offer a higher average thermal residual strain reading, while being subject to a much lower strain gradient. This particularly favors the

Fatigue Performance of Ti-6Al-4V Additively Manufactured Specimens with Integrated Capillaries of an Embedded Structural Health Monitoring System.

Science.gov (United States)

Hinderdael, Michaël; Strantza, Maria; De Baere, Dieter; Devesse, Wim; De Graeve, Iris; Terryn, Herman; Guillaume, Patrick

2017-08-25

Additive manufacturing (AM) of metals offers new possibilities for the production of complex structures. Up to now, investigations on the mechanical response of AM metallic parts show a significant spread and unexpected failures cannot be excluded. In this work, we focus on the detection of fatigue cracks through the integration of a Structural Health Monitoring (SHM) system in Ti-6Al-4V specimens. The working principle of the presented system is based on the integration of small capillaries that are capable of detecting fatigue cracks. Four-point bending fatigue tests have been performed on Ti-6Al-4V specimens with integrated capillaries and compared to the reference specimenswithout capillaries. Specimens were produced by conventional subtractive manufacturing of wrought material and AM, using the laser based Directed Energy Deposition (DED) process. In this study, we investigated the effect of the presence of the capillary on the fatigue strength and fatigue initiation location. Finite element (FEM) simulations were performed to validate the experimental test results. The presence of a drilled capillary in the specimens did not alter the fatigue initiation location. However, the laser based DED production process introduced roughness on the capillary surface that altered the fatigue initiation location to the capillary surface. The fatigue performance was greatly reduced when considering a printed capillary. It is concluded that the surface quality of the integrated capillary is of primary importance in order not to influence the structural integrity of the component to be monitored.

Monitoring Cray Cooling Systems

Energy Technology Data Exchange (ETDEWEB)

Maxwell, Don E [ORNL; Ezell, Matthew A [ORNL; Becklehimer, Jeff [Cray, Inc.; Donovan, Matthew J [ORNL; Layton, Christopher C [ORNL

2014-01-01

While sites generally have systems in place to monitor the health of Cray computers themselves, often the cooling systems are ignored until a computer failure requires investigation into the source of the failure. The Liebert XDP units used to cool the Cray XE/XK models as well as the Cray proprietary cooling system used for the Cray XC30 models provide data useful for health monitoring. Unfortunately, this valuable information is often available only to custom solutions not accessible by a center-wide monitoring system or is simply ignored entirely. In this paper, methods and tools used to harvest the monitoring data available are discussed, and the implementation needed to integrate the data into a center-wide monitoring system at the Oak Ridge National Laboratory is provided.

On switching response surface models, with applications to the structural health monitoring of bridges

Science.gov (United States)

Worden, K.; Cross, E. J.

2018-01-01

Structural Health Monitoring (SHM) is the engineering discipline of diagnosing damage and estimating safe remaining life for structures and systems. Often, SHM is accomplished by detecting changes in measured quantities from the structure of interest; if there are no competing explanations for the changes, one infers that they are the result of damage. If the structure of interest is subject to changes in its environmental or operational conditions, one must understand the effects of these changes in order that one does not falsely claim that damage has occurred when changes in measured quantities are observed. This problem - the problem of confounding influences - is particularly pressing for civil infrastructure where the given structure is usually openly exposed to the weather and may be subject to strongly varying operational conditions. One approach to understanding confounding influences is to construct a data-based response surface model that can represent measurement variations as a function of environmental and operational variables. The models can then be used to remove environmental and operational variations so that change detection algorithms signal the occurrence of damage alone. The current paper is concerned with such response surface models in the case of SHM of bridges. In particular, classes of response surface models that can switch discontinuously between regimes are discussed. Recently, it has been shown that Gaussian Process (GP) models are an effective means of developing response surface or surrogate models. However, the GP approach runs into difficulties if changes in the latent variables cause the structure of interest to abruptly switch between regimes. A good example here, which is well known in the SHM literature, is given by the Z24 Bridge in Switzerland which completely changed its dynamical behaviour when it cooled below zero degrees Celsius as the asphalt of the deck stiffened. The solution proposed here is to adopt the recently

Evaluating penetration-monitoring systems

International Nuclear Information System (INIS)

Markin, J.T.

1981-01-01

Evaluating the performance of a process monitoring system in detecting improper activities that could be related to material diversion requires a framework for addressing the complexity and statistical uncertainty of such systems. This report proposes a methodology that determines the optimal divertor strategy against a monitoring system and the system probability of detection. This method extends previous work by correctly modeling uncorrelated and correlated measurement errors for radiation monitors

Modal content based damage indicators and phased array transducers for structural health monitoring of aircraft structures using ultrasonic guided waves

Science.gov (United States)

Ren, Baiyang

Composite materials, especially carbon fiber reinforced polymers (CFRP), have been widely used in the aircraft industry because of their high specific strength and stiffness, resistance to corrosion and good fatigue life. Due to their highly anisotropic material properties and laminated structures, joining methods like bolting and riveting are no longer appropriate for joining CFRP since they initiate defects during the assembly and severely compromise the integrity of the structure; thus new techniques for joining CFRP are highly demanded. Adhesive bonding is a promising method because it relieves stress concentration, reduces weight and provides smooth surfaces. Additionally, it is a low-cost alternative to the co-cured method which is currently used to manufacture components of aircraft fuselage. Adhesive defects, disbonds at the interface between adherend and adhesive layer, are focused on in this thesis because they can be initialized by either poor surface preparation during the manufacturing or fatigue loads during service. Aircraft need structural health monitoring (SHM) systems to increase safety and reduce loss, and adhesive bonds usually represent the hotspots of the assembled structure. There are many nondestructive evaluation (NDE) methods for bond inspection. However, these methods cannot be readily integrated into an SHM system because of the bulk size and weight of the equipment and requirement of accessibility to one side of the bonded joint. The first objective of this work is to develop instruments, actuators, sensors and a data acquisition system for SHM of bond lines using ultrasonic guided waves which are well known to be able to cover large volume of the structure and inaccessible regions. Different from widely used guided wave sensors like PZT disks, the new actuators, piezoelectric fiber composite (PFC) phased array transducers0 (PAT), can control the modal content of the excited waves and the new sensors, polyvinylidene fluoride (PVDF

Environmental radiation monitoring system

International Nuclear Information System (INIS)

Kato, Tsutomu; Shioiri, Masatoshi; Sakamaki, Tsuyoshi

2007-01-01

Environmental radiation monitoring systems are used to measure and monitoring gamma-rays at the observation boundaries of nuclear facilities and in the surrounding areas. In recent years, however, few new nuclear facilities have been constructed and the monitoring systems shift to renewal of existing systems. In addition, in order to increase public acceptance, the facilities are being equipped with communication lines to provide data to prefectural environmental centers. In this text, we introduce the latest technology incorporated in replacement of environmental radiation monitoring systems. We also introduce a replacement method that can shorten the duration during which environmental dose rate measurement is interrupted by enabling both the replacement system and the system being replaced to perform measurements in parallel immediately before and after the replacement. (author)

Variations in local elastic modulus along the length of the aorta as observed by use of a scanning haptic microscope (SHM).

Science.gov (United States)

Moriwaki, Takeshi; Oie, Tomonori; Takamizawa, Keiichi; Murayama, Yoshinobu; Fukuda, Toru; Omata, Sadao; Kanda, Keiichi; Nakayama, Yasuhide

2011-12-01

Variations in microscopic elastic structures along the entire length of canine aorta were evaluated by use of a scanning haptic microscope (SHM). The total aorta from the aortic arch to the abdominal aorta was divided into 6 approximately equal segments. After embedding the aorta in agar, it was cut into horizontal circumferential segments to obtain disk-like agar portions containing ring-like samples of aorta with flat surfaces (thickness, approximately 1 mm). The elastic modulus and topography of the samples under no-load conditions were simultaneously measured along the entire thickness of the wall by SHM by using a probe with a diameter of 5 μm and a spatial resolution of 2 μm at a rate of 0.3 s/point. The elastic modulus of the wall was the highest on the side of the luminal surface and decreased gradually toward the adventitial side. This tendency was similar to that of the change in the elastin fiber content. During the evaluation of the mid-portion of each tunica media segment, the highest elastic modulus (40.8 ± 3.5 kPa) was identified at the thoracic section of the aorta that had the highest density of elastic fibers. Under no-load conditions, portions of the aorta with high elastin density have a high elastic modulus.

Integrated photovoltaic (PV) monitoring system

Science.gov (United States)

Mahinder Singh, Balbir Singh; Husain, NurSyahidah; Mohamed, Norani Muti

2012-09-01

The main aim of this research work is to design an accurate and reliable monitoring system to be integrated with solar electricity generating system. The performance monitoring system is required to ensure that the PVEGS is operating at an optimum level. The PV monitoring system is able to measure all the important parameters that determine an optimum performance. The measured values are recorded continuously, as the data acquisition system is connected to a computer, and data is stored at fixed intervals. The data can be locally used and can also be transmitted via internet. The data that appears directly on the local monitoring system is displayed via graphical user interface that was created by using Visual basic and Apache software was used for data transmission The accuracy and reliability of the developed monitoring system was tested against the data that captured simultaneously by using a standard power quality analyzer device. The high correlation which is 97% values indicates the level of accuracy of the monitoring system. The aim of leveraging on a system for continuous monitoring system is achieved, both locally, and can be viewed simultaneously at a remote system.

Structural Health Monitoring of a Composite Panel Based on PZT Sensors and a Transfer Impedance Framework.

Science.gov (United States)

Dziendzikowski, Michal; Niedbala, Patryk; Kurnyta, Artur; Kowalczyk, Kamil; Dragan, Krzysztof

2018-05-11

One of the ideas for development of Structural Health Monitoring (SHM) systems is based on excitation of elastic waves by a network of PZT piezoelectric transducers integrated with the structure. In the paper, a variant of the so-called Transfer Impedance (TI) approach to SHM is followed. Signal characteristics, called the Damage Indices (DIs), were proposed for data presentation and analysis. The idea underlying the definition of DIs was to maintain most of the information carried by the voltage induced on PZT sensors by elastic waves. In particular, the DIs proposed in the paper should be sensitive to all types of damage which can influence the amplitude or the phase of the voltage induced on the sensor. Properties of the proposed DIs were investigated experimentally using a GFRP composite panel equipped with PZT networks attached to its surface and embedded into its internal structure. Repeatability and stability of DI indications under controlled conditions were verified in tests. Also, some performance indicators for surface-attached and structure-embedded sensors were obtained. The DIs' behavior was dependent mostly on the presence of a simulated damage in the structure. Anisotropy of mechanical properties of the specimen, geometrical properties of PZT network as well as, to some extent, the technology of sensor integration with the structure were irrelevant for damage indication. This property enables the method to be used for damage detection and classification.

A practical monitoring system for the structural safety of mega-trusses using wireless vibrating wire strain gauges.

Science.gov (United States)

Park, Hyo Seon; Lee, Hwan Young; Choi, Se Woon; Kim, Yousok

2013-12-16

Sensor technologies have been actively employed in structural health monitoring (SHM) to evaluate structural safety. To provide stable and real-time monitoring, a practical wireless sensor network system (WSNS) based on vibrating wire strain gauges (VWSGs) is proposed and applied to a building under construction. In this WSNS, the data measured from each VWSG are transmitted to the sensor node via a signal line and then transmitted to the master node through a short-range wireless communication module (operating on the Industrial, Scientific, and Medical (ISM) band). The master node also employs a long-range wireless communication module (Code Division Multiple Access-CDMA) to transmit the received data from the sensor node to a server located in a remote area, which enables a manager to examine the measured data in real time without any time or location restrictions. In this study, a total of 48 VWSGs, 14 sensor nodes, and seven master nodes were implemented to measure long-term strain variations of mega-trusses in an irregular large-scale building under construction. Based on strain data collected over a 16-month period, a quantitative evaluation of the construction process was performed to determine the aspects that exhibit the greatest influence on member behavior and to conduct a comparison with numerical simulation results. The effect of temperature stress on the structural elements was also analyzed. From these observations, the feasibility of a long-term WSNS based on VWSGs to evaluate the structural safety of an irregular building under construction was confirmed.

A Practical Monitoring System for the Structural Safety of Mega-Trusses Using Wireless Vibrating Wire Strain Gauges

Directory of Open Access Journals (Sweden)

Hyo Seon Park

2013-12-01

Full Text Available Sensor technologies have been actively employed in structural health monitoring (SHM to evaluate structural safety. To provide stable and real-time monitoring, a practical wireless sensor network system (WSNS based on vibrating wire strain gauges (VWSGs is proposed and applied to a building under construction. In this WSNS, the data measured from each VWSG are transmitted to the sensor node via a signal line and then transmitted to the master node through a short-range wireless communication module (operating on the Industrial, Scientific, and Medical (ISM band. The master node also employs a long-range wireless communication module (Code Division Multiple Access—CDMA to transmit the received data from the sensor node to a server located in a remote area, which enables a manager to examine the measured data in real time without any time or location restrictions. In this study, a total of 48 VWSGs, 14 sensor nodes, and seven master nodes were implemented to measure long-term strain variations of mega-trusses in an irregular large-scale building under construction. Based on strain data collected over a 16-month period, a quantitative evaluation of the construction process was performed to determine the aspects that exhibit the greatest influence on member behavior and to conduct a comparison with numerical simulation results. The effect of temperature stress on the structural elements was also analyzed. From these observations, the feasibility of a long-term WSNS based on VWSGs to evaluate the structural safety of an irregular building under construction was confirmed.

Investigation on the use of artificial neural networks to overcome the effects of environmental and operational changes on guided waves monitoring

Science.gov (United States)

El Mountassir, M.; Yaacoubi, S.; Dahmene, F.

2015-07-01

Intelligent feature extraction and advanced signal processing techniques are necessary for a better interpretation of ultrasonic guided waves signals either in structural health monitoring (SHM) or in nondestructive testing (NDT). Such signals are characterized by at least multi-modal and dispersive components. In addition, in SHM, these signals are closely vulnerable to environmental and operational conditions (EOCs), and can be severely affected. In this paper we investigate the use of Artificial Neural Network (ANN) to overcome these effects and to provide a reliable damage detection method with a minimal of false indications. An experimental case of study (full scale pipe) is presented. Damages sizes have been increased and their shapes modified in different steps. Various parameters such as the number of inputs and the number of hidden neurons were studied to find the optimal configuration of the neural network.

Value of information

DEFF Research Database (Denmark)

Straub, D.; Chatzi, E.; Bismut, E.

2017-01-01

The concept of value of information (VoI) enables quantification of the benefits provided by structural health monitoring (SHM) systems –in principle. Its implementation is challenging, as it requires an explicit modelling of the structural system’s life cycle, in particular of the decisions...... that are taken based on the SHM information. In this paper, we approach the VoI analysis through an influence diagram (ID), which supports the modelling process. We provide a simple example for illustration and discuss challenges associated with real-life implementation...

Full-scale experimental validation of decentralized damage identification using wireless smart sensors

International Nuclear Information System (INIS)

Jang, Shinae; Sim, Sung-Han; Jo, Hongki; Spencer Jr, Billie F

2012-01-01

Wireless smart sensor networks (WSSN) facilitate a new paradigm for structural health monitoring (SHM) of civil infrastructure. Conventionally, SHM systems employing wired sensors and centralized data acquisition have been used to characterize the state of a structure; however, widespread implementation has been limited due to high costs and difficulties in installation. WSSN offer a unique opportunity to overcome such difficulties. Recent developments have realized low-cost, smart sensors with on-board computation and wireless communication capabilities, making deployment of a dense array of sensors on large civil structures both economical and feasible. Wireless smart sensors (WSS) have shown their tremendous potential for SHM in recent full-scale bridge monitoring examples. However, structural damage identification using on-board computation capability in a WSSN, a primary objective of SHM, has yet to reach its full potential. This paper presents full-scale validation of a damage identification strategy using a decentralized network of Imote2 nodes on a historic steel truss bridge. A total of 24 WSS nodes with 144 sensor channels are deployed on the bridge to validate the developed damage identification software. The performance of this decentralized damage identification strategy is demonstrated on the WSSN by comparing its results with those from the traditional centralized approach, as well as visual inspection. (paper)

Inductive Monitoring System (IMS)

Data.gov (United States)

National Aeronautics and Space Administration — IMS: Inductive Monitoring System The Inductive Monitoring System (IMS) is a tool that uses a data mining technique called clustering to extract models of normal...

CERN safety system monitoring - SSM

International Nuclear Information System (INIS)

Hakulinen, T.; Ninin, P.; Valentini, F.; Gonzalez, J.; Salatko-Petryszcze, C.

2012-01-01

CERN SSM (Safety System Monitoring) is a system for monitoring state-of-health of the various access and safety systems of the CERN site and accelerator infrastructure. The emphasis of SSM is on the needs of maintenance and system operation with the aim of providing an independent and reliable verification path of the basic operational parameters of each system. Included are all network-connected devices, such as PLCs (local purpose control unit), servers, panel displays, operator posts, etc. The basic monitoring engine of SSM is a freely available system-monitoring framework Zabbix, on top of which a simplified traffic-light-type web-interface has been built. The web-interface of SSM is designed to be ultra-light to facilitate access from hand-held devices over slow connections. The underlying Zabbix system offers history and notification mechanisms typical of advanced monitoring systems. (authors)

Copilot: Monitoring Embedded Systems

Science.gov (United States)

Pike, Lee; Wegmann, Nis; Niller, Sebastian; Goodloe, Alwyn

2012-01-01

Runtime verification (RV) is a natural fit for ultra-critical systems, where correctness is imperative. In ultra-critical systems, even if the software is fault-free, because of the inherent unreliability of commodity hardware and the adversity of operational environments, processing units (and their hosted software) are replicated, and fault-tolerant algorithms are used to compare the outputs. We investigate both software monitoring in distributed fault-tolerant systems, as well as implementing fault-tolerance mechanisms using RV techniques. We describe the Copilot language and compiler, specifically designed for generating monitors for distributed, hard real-time systems. We also describe two case-studies in which we generated Copilot monitors in avionics systems.

An optimal baseline selection methodology for data-driven damage detection and temperature compensation in acousto-ultrasonics

International Nuclear Information System (INIS)

Torres-Arredondo, M-A; Sierra-Pérez, Julián; Cabanes, Guénaël

2016-01-01

The process of measuring and analysing the data from a distributed sensor network all over a structural system in order to quantify its condition is known as structural health monitoring (SHM). For the design of a trustworthy health monitoring system, a vast amount of information regarding the inherent physical characteristics of the sources and their propagation and interaction across the structure is crucial. Moreover, any SHM system which is expected to transition to field operation must take into account the influence of environmental and operational changes which cause modifications in the stiffness and damping of the structure and consequently modify its dynamic behaviour. On that account, special attention is paid in this paper to the development of an efficient SHM methodology where robust signal processing and pattern recognition techniques are integrated for the correct interpretation of complex ultrasonic waves within the context of damage detection and identification. The methodology is based on an acousto-ultrasonics technique where the discrete wavelet transform is evaluated for feature extraction and selection, linear principal component analysis for data-driven modelling and self-organising maps for a two-level clustering under the principle of local density. At the end, the methodology is experimentally demonstrated and results show that all the damages were detectable and identifiable. (paper)

An optimal baseline selection methodology for data-driven damage detection and temperature compensation in acousto-ultrasonics

Science.gov (United States)

Torres-Arredondo, M.-A.; Sierra-Pérez, Julián; Cabanes, Guénaël

2016-05-01

The process of measuring and analysing the data from a distributed sensor network all over a structural system in order to quantify its condition is known as structural health monitoring (SHM). For the design of a trustworthy health monitoring system, a vast amount of information regarding the inherent physical characteristics of the sources and their propagation and interaction across the structure is crucial. Moreover, any SHM system which is expected to transition to field operation must take into account the influence of environmental and operational changes which cause modifications in the stiffness and damping of the structure and consequently modify its dynamic behaviour. On that account, special attention is paid in this paper to the development of an efficient SHM methodology where robust signal processing and pattern recognition techniques are integrated for the correct interpretation of complex ultrasonic waves within the context of damage detection and identification. The methodology is based on an acousto-ultrasonics technique where the discrete wavelet transform is evaluated for feature extraction and selection, linear principal component analysis for data-driven modelling and self-organising maps for a two-level clustering under the principle of local density. At the end, the methodology is experimentally demonstrated and results show that all the damages were detectable and identifiable.

Waste monitoring system for effluents

International Nuclear Information System (INIS)

Macdonald, J.M.; Gomez, B.; Trujillo, L.; Malcom, J.E.; Nekimken, H.; Pope, N.; Bibeau, R.

1995-07-01

The waste monitoring system in use at Los Alamos National Laboratory's Plutonium Facility, TA-55, is a computer-based system that proves real-time information on industrial effluents. Remote computers monitor discharge events and data moves from one system to another via a local area network. This report describes the history, system design, summary, instrumentation list, displays, trending screens, and layout of the waste monitoring system

Monitoring the Damage State of Fiber Reinforced Composites Using an FBG Network for Failure Prediction

Directory of Open Access Journals (Sweden)

Esat Selim Kocaman

2017-01-01

Full Text Available A structural health monitoring (SHM study of biaxial glass fibre-reinforced epoxy matrix composites under a constant, high strain uniaxial fatigue loading is performed using fibre Bragg grating (FBG optical sensors embedded in composites at various locations to monitor the evolution of local strains, thereby understanding the damage mechanisms. Concurrently, the temperature changes of the samples during the fatigue test have also been monitored at the same locations. Close to fracture, significant variations in local temperatures and strains are observed, and it is shown that the variations in temperature and strain can be used to predict imminent fracture. It is noted that the latter information cannot be obtained using external strain gages, which underlines the importance of the tracking of local strains internally.

VME system monitor board

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-02-01

Much of the machinery throughout the APS will be controlled by VME based computers. In order to increase the reliability of the system, it is necessary to be able to monitor the status of each VME crate. In order to do this, a VME System Monitor was created. In addition to being able to monitor and report the status (watchdog timer, temperature, CPU (Motorola MVME 167) state (status, run, fail), and the power supply), it includes provisions to remotely reset the CPU and VME crate, digital I/O, and parts of the transition module (serial port and ethernet connector) so that the Motorla MVME 712 is not needed. The standard VME interface was modified on the System Monitor so that in conjunction with the Motorola MVME 167 a message based VXI interrupt handler could is implemented. The System Monitor is a single VME card (6U). It utilizes both the front panel and the P2 connector for I/O. The front panel contains a temperature monitor, watchdog status LED, 4 general status LEDs, input for a TTL interrupt, 8 binary inputs (24 volt, 5 volt, and dry contact sense), 4 binary outputs (dry contact, TTL, and 100 mA), serial port (electrical RS-232 or fiber optic), ethernet transceiver (10 BASE-FO or AUI), and a status link to neighbor crates. The P2 connector is used to provide the serial port and ethernet to the processor. In order to abort and read the status of the CPU, a jumper cable must be connected between the CPU and the System Monitor.

A framework for data compression and damage detection in structural health monitoring applied on a laboratory three-story structure

Directory of Open Access Journals (Sweden)

Manoel Afonso Pereira de Lima

2016-09-01

Full Text Available Structural Health Monitoring (SHM is an important technique used to preserve many types of structures in the short and long run, using sensor networks to continuously gather the desired data. However, this causes a strong impact in the data size to be stored and processed. A common solution to this is using compression algorithms, where the level of data compression should be adequate enough to allow the correct damage identification. In this work, we use the data sets from a laboratory three-story structure to evaluate the performance of common compression algorithms which, then, are combined with damage detection algorithms used in SHM. We also analyze how the use of Independent Component Analysis, a common technique to reduce noise in raw data, can assist the detection performance. The results showed that Piecewise Linear Histogram combined with Nonlinear PCA have the best trade-off between compression and detection for small error thresholds while Adaptive PCA with Principal Component Analysis perform better with higher values.

Long term cross asset management of critical structures

International Nuclear Information System (INIS)

Wenzel, H.

2013-01-01

Conclusions: Asset management requires tools for optimisation. SHM delivers the required information. SHM helps to reduce the uncertainties. Life Cycle methodologies are mature. Life Time Extension can be justified and monitored. Life Cycle Engineering is a must nowadays

Environmental monitoring and information systems

International Nuclear Information System (INIS)

Gibbert, R.

1998-01-01

Environmental monitoring and information systems installed by Dornier are summarized. A broad spectrum of environmental areas from air quality and water to radioactivity is covered. Nuclear power plant monitoring systems, either as remote or plant-internal monitoring systems, form an important element of the work undertaken. The systems delivered covered local, regional or national areas. The range of services provided, and hardware and software platforms are listed. (R.P.)

Data monitoring system of technical diagnosis system for EAST

International Nuclear Information System (INIS)

Qian Jing; Weng Peide; Chen Zhuomin; Wu Yu; Xi Weibin; Luo Jiarong

2010-01-01

Technical diagnosis system (TDS) is an important subsystem to monitor status parameters of EAST (experimental advanced superconducting tokamak). The upgraded TDS data monitoring system is comprised of management floor, monitoring floor and field floor.. Security protection, malfunction record and analysis are designed to make the system stable, robust and friendly. During the past EAST campaigns, the data monitoring system has been operated reliably and stably. The signal conditioning system and software architecture are described. (authors)

A Structural Model Decomposition Framework for Systems Health Management

Data.gov (United States)

National Aeronautics and Space Administration — Systems health management (SHM) is an impor- tant set of technologies aimed at increasing system safety and reliability by detecting, isolating, and identifying...

The JOYO remote monitoring system

International Nuclear Information System (INIS)

Damico, Joseph P.; Hashimoto, Yu

2000-01-01

The evolution of the personal computer, operating systems and applications software and the Internet has brought drastic change and many benefits worldwide. Remote monitoring systems benefit from computer network and other modern software technologies. The availability of fast, inexpensive and secure communications enables new solutions for monitoring system applications. The JOYO Remote Monitoring System (RMS) utilizes computer network communications and modular software design to provide a distributed integrated solution for monitoring multiple storage locations. This paper describes the remote monitoring system installed at the JOYO Fast Reactor. The system combines sensors, software, and computer network technologies to create a powerful data collection, storage and dissemination capability. The RMS provides a flexible, scalable solution for a variety of applications. The RMS integrates a variety of state of the art technologies from several sources and serves as a test bed for cutting edge technologies that can be shared with outside users. This paper describes the system components and their operation and discusses system benefits. Current activities and future plants for the JOYO RMS will be discussed. (author)

Unattended Monitoring System Design Methodology

International Nuclear Information System (INIS)

Drayer, D.D.; DeLand, S.M.; Harmon, C.D.; Matter, J.C.; Martinez, R.L.; Smith, J.D.

1999-01-01

A methodology for designing Unattended Monitoring Systems starting at a systems level has been developed at Sandia National Laboratories. This proven methodology provides a template that describes the process for selecting and applying appropriate technologies to meet unattended system requirements, as well as providing a framework for development of both training courses and workshops associated with unattended monitoring. The design and implementation of unattended monitoring systems is generally intended to respond to some form of policy based requirements resulting from international agreements or domestic regulations. Once the monitoring requirements are established, a review of the associated process and its related facilities enables identification of strategic monitoring locations and development of a conceptual system design. The detailed design effort results in the definition of detection components as well as the supporting communications network and data management scheme. The data analyses then enables a coherent display of the knowledge generated during the monitoring effort. The resultant knowledge is then compared to the original system objectives to ensure that the design adequately addresses the fundamental principles stated in the policy agreements. Implementation of this design methodology will ensure that comprehensive unattended monitoring system designs provide appropriate answers to those critical questions imposed by specific agreements or regulations. This paper describes the main features of the methodology and discusses how it can be applied in real world situations

Savannah River Plant remote environmental monitoring system

International Nuclear Information System (INIS)

Schubert, J.F.

1987-01-01

The SRP remote environmental monitoring system consists of separations facilities stack monitors, production reactor stack monitors, twelve site perimeter monitors, river and stream monitors, a geostationary operational environmental satellite (GOES) data link, reactor cooling lake thermal monitors, meteorological tower system, Weather Information and Display (WIND) system computer, and the VANTAGE data base management system. The remote environmental monitoring system when fully implemented will provide automatic monitoring of key stack releases and automatic inclusion of these source terms in the emergency response codes

Arduino Based Infant Monitoring System

Science.gov (United States)

Farhanah Mohamad Ishak, Daing Noor; Jamil, Muhammad Mahadi Abdul; Ambar, Radzi

2017-08-01

This paper proposes a system for monitoring infant in an incubator and records the relevant data into a computer. The data recorded by the system can be further referred by the neonatal intensive care unit (NICU) personnel for diagnostic or research purposes. The study focuses on designing the monitoring system that consists of an incubator equipped with humidity sensor to measure the humidity level, and a pulse sensor that can be attached on an infant placed inside the incubator to monitor infant’s heart pulse. The measurement results which are the pulse rate and humidity level are sent to the PC via Arduino microcontroller. The advantage of this system will be that in the future, it may also enable doctors to closely monitor the infant condition through local area network and internet. This work is aimed as an example of an application that contributes towards remote tele-health monitoring system.

Is it worth changing pattern recognition methods for structural health monitoring?

Science.gov (United States)

Bull, L. A.; Worden, K.; Cross, E. J.; Dervilis, N.

2017-05-01

The key element of this work is to demonstrate alternative strategies for using pattern recognition algorithms whilst investigating structural health monitoring. This paper looks to determine if it makes any difference in choosing from a range of established classification techniques: from decision trees and support vector machines, to Gaussian processes. Classification algorithms are tested on adjustable synthetic data to establish performance metrics, then all techniques are applied to real SHM data. To aid the selection of training data, an informative chain of artificial intelligence tools is used to explore an active learning interaction between meaningful clusters of data.

Monitoring and evaluation of wire mesh forming life

Science.gov (United States)

Enemuoh, Emmanuel U.; Zhao, Ping; Kadlec, Alec

2018-03-01

Forming tables are used with stainless steel wire mesh conveyor belts to produce variety of products. The forming tables will typically run continuously for several days, with some hours of scheduled downtime for maintenance, cleaning and part replacement after several weeks of operation. The wire mesh conveyor belts show large variation in their remaining life due to associated variations in their nominal thicknesses. Currently the industry is dependent on seasoned operators to determine the replacement time for the wire mesh formers. The drawback of this approach is inconsistency in judgements made by different operators and lack of data knowledge that can be used to develop decision making system that will be more consistent with wire mesh life prediction and replacement time. In this study, diagnostic measurements about the health of wire mesh former is investigated and developed. The wire mesh quality characteristics considered are thermal measurement, tension property, gage thickness, and wire mesh wear. The results show that real time thermal sensor and wear measurements would provide suitable data for the estimation of wire mesh failure, therefore, can be used as a diagnostic parameter for developing structural health monitoring (SHM) system for stainless steel wire mesh formers.

Structural health monitoring for bolt loosening via a non-invasive vibro-haptics human-machine cooperative interface

Science.gov (United States)

Pekedis, Mahmut; Mascerañas, David; Turan, Gursoy; Ercan, Emre; Farrar, Charles R.; Yildiz, Hasan

2015-08-01

For the last two decades, developments in damage detection algorithms have greatly increased the potential for autonomous decisions about structural health. However, we are still struggling to build autonomous tools that can match the ability of a human to detect and localize the quantity of damage in structures. Therefore, there is a growing interest in merging the computational and cognitive concepts to improve the solution of structural health monitoring (SHM). The main object of this research is to apply the human-machine cooperative approach on a tower structure to detect damage. The cooperation approach includes haptic tools to create an appropriate collaboration between SHM sensor networks, statistical compression techniques and humans. Damage simulation in the structure is conducted by releasing some of the bolt loads. Accelerometers are bonded to various locations of the tower members to acquire the dynamic response of the structure. The obtained accelerometer results are encoded in three different ways to represent them as a haptic stimulus for the human subjects. Then, the participants are subjected to each of these stimuli to detect the bolt loosened damage in the tower. Results obtained from the human-machine cooperation demonstrate that the human subjects were able to recognize the damage with an accuracy of 88 ± 20.21% and response time of 5.87 ± 2.33 s. As a result, it is concluded that the currently developed human-machine cooperation SHM may provide a useful framework to interact with abstract entities such as data from a sensor network.

Distributed adaptive diagnosis of sensor faults using structural response data

Science.gov (United States)

Dragos, Kosmas; Smarsly, Kay

2016-10-01

The reliability and consistency of wireless structural health monitoring (SHM) systems can be compromised by sensor faults, leading to miscalibrations, corrupted data, or even data loss. Several research approaches towards fault diagnosis, referred to as ‘analytical redundancy’, have been proposed that analyze the correlations between different sensor outputs. In wireless SHM, most analytical redundancy approaches require centralized data storage on a server for data analysis, while other approaches exploit the on-board computing capabilities of wireless sensor nodes, analyzing the raw sensor data directly on board. However, using raw sensor data poses an operational constraint due to the limited power resources of wireless sensor nodes. In this paper, a new distributed autonomous approach towards sensor fault diagnosis based on processed structural response data is presented. The inherent correlations among Fourier amplitudes of acceleration response data, at peaks corresponding to the eigenfrequencies of the structure, are used for diagnosis of abnormal sensor outputs at a given structural condition. Representing an entirely data-driven analytical redundancy approach that does not require any a priori knowledge of the monitored structure or of the SHM system, artificial neural networks (ANN) are embedded into the sensor nodes enabling cooperative fault diagnosis in a fully decentralized manner. The distributed analytical redundancy approach is implemented into a wireless SHM system and validated in laboratory experiments, demonstrating the ability of wireless sensor nodes to self-diagnose sensor faults accurately and efficiently with minimal data traffic. Besides enabling distributed autonomous fault diagnosis, the embedded ANNs are able to adapt to the actual condition of the structure, thus ensuring accurate and efficient fault diagnosis even in case of structural changes.

Review on pressure sensors for structural health monitoring

Science.gov (United States)

Sikarwar, Samiksha; Satyendra; Singh, Shakti; Yadav, Bal Chandra

2017-12-01

This paper reports the state of art in a variety of pressure and the detailed study of various matrix based pressure sensors. The performances of the bridges, buildings, etc. are threatened by earthquakes, material degradations, and other environmental effects. Structural health monitoring (SHM) is crucial to protect the people and also for assets planning. This study is a contribution in developing the knowledge about self-sensing smart materials and structures for the construction industry. It deals with the study of self-sensing as well as mechanical and electrical properties of different matrices based on pressure sensors. The relationships among the compression, tensile strain, and crack length with electrical resistance change are also reviewed.

System health monitoring

International Nuclear Information System (INIS)

Reneke, J.A.; Fryer, M.O.

1995-01-01

Well designed large systems include many instrument taking data. These data are used in a variety of ways. They are used to control the system and its components, to monitor system and component health, and often for historical or financial purposes. This paper discusses a new method of using data from low level instrumentation to monitor system and component health. The method uses the covariance of instrument outputs to calculate a measure of system change. The method involves no complicated modeling since it is not a parameter estimation algorithm. The method is iterative and can be implemented on a computer in real time. Examples are presented for a metal lathe and a high efficiency particulate air (HEPA) filter. It is shown that the proposed method is quite sensitive to system changes such as wear out and failure. The method is useful for low level system diagnostics and fault detection

Strength and fatigue life evaluation of composite laminate with embedded sensors

Science.gov (United States)

Rathod, Vivek T.; Hiremath, S. R.; Roy Mahapatra, D.

2014-04-01

Prognosis regarding durability of composite structures using various Structural Health Monitoring (SHM) techniques is an important and challenging topic of research. Ultrasonic SHM systems with embedded transducers have potential application here due to their instant monitoring capability, compact packaging potential toward unobtrusiveness and noninvasiveness as compared to non-contact ultrasonic and eddy current techniques which require disassembly of the structure. However, embedded sensors pose a risk to the structure by acting as a flaw thereby reducing life. The present paper focuses on the determination of strength and fatigue life of the composite laminate with embedded film sensors like CNT nanocomposite, PVDF thin films and piezoceramic films. First, the techniques of embedding these sensors in composite laminates is described followed by the determination of static strength and fatigue life at coupon level testing in Universal Testing Machine (UTM). Failure mechanisms of the composite laminate with embedded sensors are studied for static and dynamic loading cases. The coupons are monitored for loading and failure using the embedded sensors. A comparison of the performance of these three types of embedded sensors is made to study their suitability in various applications. These three types of embedded sensors cover a wide variety of applications, and prove to be viable in embedded sensor based SHM of composite structures.

Integrated Monitoring System of Production Processes

Directory of Open Access Journals (Sweden)

Oborski Przemysław

2016-12-01

Full Text Available Integrated monitoring system for discrete manufacturing processes is presented in the paper. The multilayer hardware and software reference model was developed. Original research are an answer for industry needs of the integration of information flow in production process. Reference model corresponds with proposed data model based on multilayer data tree allowing to describe orders, products, processes and save monitoring data. Elaborated models were implemented in the integrated monitoring system demonstrator developed in the project. It was built on the base of multiagent technology to assure high flexibility and openness on applying intelligent algorithms for data processing. Currently on the base of achieved experience an application integrated monitoring system for real production system is developed. In the article the main problems of monitoring integration are presented, including specificity of discrete production, data processing and future application of Cyber-Physical-Systems. Development of manufacturing systems is based more and more on taking an advantage of applying intelligent solutions into machine and production process control and monitoring. Connection of technical systems, machine tools and manufacturing processes monitoring with advanced information processing seems to be one of the most important areas of near future development. It will play important role in efficient operation and competitiveness of the whole production system. It is also important area of applying in the future Cyber-Physical-Systems that can radically improve functionally of monitoring systems and reduce the cost of its implementation.

Maintenance of radiation monitoring systems

International Nuclear Information System (INIS)

Aoyama, Kei

2001-01-01

As the safety and quality of atomic power facilities are more strongly required, the reliability improvement and preventive maintenance of radiation monitoring systems are important. This paper describes the maintenance of radiation monitoring systems delivered by Fuji Electric and the present status of preventive maintenance technology. Also it introduces the case that we developed a fault diagnosis function adopting a statistics technique and artificial intelligence (AI) and delivered a radiation monitoring system including this function. This system can output a fault analysis result and a countermeasure from the computer in real time. (author)

Configuration of Risk Monitor System by PLant Defense-In.Depth Monitor and Relability Monitor

DEFF Research Database (Denmark)

Yoshikawa, Hidekazu; Lind, Morten; Yang, Ming

2012-01-01

A new method of risk monitor system of a nuclear power plant has been proposed from the aspect by what degree of safety functions incorporated in the plant system is maintained by multiple barriers of defense-in-depth (DiD). Wherein, the central idea is plant DiD risk monitor and reliability...... monitor derived from the four aspects of (i) design principle of nuclear safety to realize DiD concept, (ii) definition of risk and risk to be monitored, (iii) severe accident phenomena as major risk, (iv) scheme of risk ranking, and (v) dynamic risk display. In this paper, the overall frame...... of the proposed frame on risk monitor system is summarized and the detailed discussion is made on the definitions of major terminologies of risk, risk ranking, anatomy of fault occurrence, two-layer configuration of risk monitor, how to configure individual elements of plant DiD risk monitor and its example...

Configuration of risk monitor system by plant defense-in-depth risk monitor and reliability monitor

International Nuclear Information System (INIS)

Yoshikawa, Hidekazu; Lind Morten; Yang Ming; Hashim Muhammad; Zhang Zhijian

2012-01-01

A new method of risk monitor system of a nuclear power plant has been proposed from the aspect by what degree of safety functions incorporated in the plant system is maintained by multiple barriers of defense-in-depth (DiD). Wherein, the central idea is plant DiD risk monitor and reliability monitor derived from the five aspects of (1) design principle of nuclear safety based on DiD concept, (2) definition of risk and risk to be monitored, (3) severe accident phenomena as major risk, (4) scheme of risk ranking, and (5) dynamic risk display. In this paper, the overall frame of the proposed risk monitor system is summarized and the detailed discussion is made on major items such as definition of risk and risk ranking, anatomy of fault occurrence, two-layer configuration of risk monitor, how to configure individual elements of plant DiD risk monitor, and lastly how to apply for a PWR safety system. (author)

The Danish Marine Monitoring System

DEFF Research Database (Denmark)

Ærtebjerg, G.

1997-01-01

Indeholder abstracts fra Workshop on Marine Monitoring Systems and Technology, Risø, 17-18 April 1996.......Indeholder abstracts fra Workshop on Marine Monitoring Systems and Technology, Risø, 17-18 April 1996....

Computer-controlled radiation monitoring system

International Nuclear Information System (INIS)

Homann, S.G.

1994-01-01

A computer-controlled radiation monitoring system was designed and installed at the Lawrence Livermore National Laboratory's Multiuser Tandem Laboratory (10 MV tandem accelerator from High Voltage Engineering Corporation). The system continuously monitors the photon and neutron radiation environment associated with the facility and automatically suspends accelerator operation if preset radiation levels are exceeded. The system has proved reliable real-time radiation monitoring over the past five years, and has been a valuable tool for maintaining personnel exposure as low as reasonably achievable

Corrosion Monitoring System

Energy Technology Data Exchange (ETDEWEB)

Dr. Russ Braunling

2004-10-31

The Corrosion Monitoring System (CMS) program developed and demonstrated a continuously on-line system that provides real-time corrosion information. The program focused on detecting pitting corrosion in its early stages. A new invention called the Intelligent Ultrasonic Probe (IUP) was patented on the program. The IUP uses ultrasonic guided waves to detect small defects and a Synthetic Aperture Focusing Technique (SAFT) algorithm to provide an image of the pits. Testing of the CMS demonstrated the capability to detect pits with dimensionality in the sub-millimeter range. The CMS was tested in both the laboratory and in a pulp and paper industrial plant. The system is capable of monitoring the plant from a remote location using the internet.

Experimental Research on Quick Structural Health Monitoring Technique for Bridges Using Smartphone

Directory of Open Access Journals (Sweden)

Xuefeng Zhao

2016-01-01

Full Text Available In the recent years, with the development and popularization of smartphone, the utilization of smartphone in the Structural Health Monitoring (SHM has attracted increasing attention owing to its unique feature. Since bridges are of great importance to society and economy, bridge health monitoring has very practical significance during its service life. Furthermore, rapid damage assessment of bridge after an extreme event such as earthquake is very important in the recovery work. Smartphone-based bridge health monitoring and postevent damage evaluation have advantages over the conventional monitoring techniques, such as low cost, ease of installation, and convenience. Therefore, this study investigates the implementation feasibility of the quick bridge health monitoring technique using smartphone. A novel vision-based cable force measurement method using smartphone camera is proposed, and, then, its feasibility and practicality is initially validated through cable model test. An experiment regarding multiple parameters monitoring of one bridge scale model is carried out. Parameters, such as acceleration, displacement, and angle, are monitored using smartphone. The experiment results show that there is a good agreement between the reference sensor and smartphone measurements in both time and frequency domains.

Gas House Autonomous System Monitoring

Science.gov (United States)

Miller, Luke; Edsall, Ashley

2015-01-01

Gas House Autonomous System Monitoring (GHASM) will employ Integrated System Health Monitoring (ISHM) of cryogenic fluids in the High Pressure Gas Facility at Stennis Space Center. The preliminary focus of development incorporates the passive monitoring and eventual commanding of the Nitrogen System. ISHM offers generic system awareness, adept at using concepts rather than specific error cases. As an enabler for autonomy, ISHM provides capabilities inclusive of anomaly detection, diagnosis, and abnormality prediction. Advancing ISHM and Autonomous Operation functional capabilities enhances quality of data, optimizes safety, improves cost effectiveness, and has direct benefits to a wide spectrum of aerospace applications.

Coolant monitoring systems for PWR reactors

International Nuclear Information System (INIS)

Luzhnov, A.M.; Morozov, V.V.; Tsypin, S.G.

1987-01-01

The ways of improving information capacity of existing monitoring systems and the necessity of designing new ones for coolant monitoring are reviewed. A wide research program on development of coolant monitoring systems in PWR reactors is analyzed. The possible applications of in-core and out-of-core detectors for coolant monitoring are demonstrated

Monitoring of Danish marketed solar heating systems

International Nuclear Information System (INIS)

Ellehauge, K.

1993-01-01

The paper describes the monitoring of manufactured solar heating systems for domestic hot water combined with space heating and systems for domestic hot water only. Results from the monitoring of 5 marketed combined systems for domestic hot water and space heating are presented. The systems situated at one family houses at different sites in Denmark have been monitored from January/February 1992. For the detailed monitoring of manufactured systems only for domestic hot water a test facility for simultaneous monitoring of 5 solar heating systems has been established at the Thermal Insulation Laboratory. (au)

Radiation monitor system for nuclear power plants

International Nuclear Information System (INIS)

Wu Bingzhe; Guo Shusheng

1990-12-01

The system has 8 kinds of radiation monitors and 2 stage microcomputers designed for processing the data from each monitor, storaging the information, printing out and displaying on the colour CRT. The function of the system includes high-value alarm, warm alarm and failure alarm, so called t hree-level alarms . Two functions of the alarms are the threshold alarm and the tendency alarm, so that this system is an intelligency system. This system has high reliability and very wide range when LOCA accident takes place. It is aseismic and immune to industrial interference. The system can meet IEC-761-1 standard and is of nuclear safety 3rd class. Also the following monitors were designed: 133 Xe monitor, 131 I monitor, low-level liquid monitor and high radiation γ area monitor. The system can meet the requirements of nuclear power plants

Monitoring system and methods for a distributed and recoverable digital control system

Science.gov (United States)

Stange, Kent (Inventor); Hess, Richard (Inventor); Kelley, Gerald B (Inventor); Rogers, Randy (Inventor)

2010-01-01

A monitoring system and methods are provided for a distributed and recoverable digital control system. The monitoring system generally comprises two independent monitoring planes within the control system. The first monitoring plane is internal to the computing units in the control system, and the second monitoring plane is external to the computing units. The internal first monitoring plane includes two in-line monitors. The first internal monitor is a self-checking, lock-step-processing monitor with integrated rapid recovery capability. The second internal monitor includes one or more reasonableness monitors, which compare actual effector position with commanded effector position. The external second monitor plane includes two monitors. The first external monitor includes a pre-recovery computing monitor, and the second external monitor includes a post recovery computing monitor. Various methods for implementing the monitoring functions are also disclosed.

A Grid job monitoring system

Energy Technology Data Exchange (ETDEWEB)

Dumitrescu, Catalin [Fermi National Accelerator Laboratory (United States); Nowack, Andreas [RWTH Aachen (Germany); Padhi, Sanjay [University of California San Diego (United States); Sarkar, Subir, E-mail: subir.sarkar@cern.c [INFN, Sezione di Pisa and Scuola Normale Superiore, Pisa (Italy)

2010-04-01

This paper presents a web-based Job Monitoring framework for individual Grid sites that allows users to follow in detail their jobs in quasi-real time. The framework consists of several independent components : (a) a set of sensors that run on the site CE and worker nodes and update a database, (b) a simple yet extensible web services framework and (c) an Ajax powered web interface having a look-and-feel and control similar to a desktop application. The monitoring framework supports LSF, Condor and PBS-like batch systems. This is one of the first monitoring systems where an X.509 authenticated web interface can be seamlessly accessed by both end-users and site administrators. While a site administrator has access to all the possible information, a user can only view the jobs for the Virtual Organizations (VO) he/she is a part of. The monitoring framework design supports several possible deployment scenarios. For a site running a supported batch system, the system may be deployed as a whole, or existing site sensors can be adapted and reused with the web services components. A site may even prefer to build the web server independently and choose to use only the Ajax powered web interface. Finally, the system is being used to monitor a glideinWMS instance. This broadens the scope significantly, allowing it to monitor jobs over multiple sites.

A grid job monitoring system

International Nuclear Information System (INIS)

Dumitrescu, Catalin; Nowack, Andreas; Padhi, Sanjay; Sarkar, Subir

2010-01-01

This paper presents a web-based Job Monitoring framework for individual Grid sites that allows users to follow in detail their jobs in quasi-real time. The framework consists of several independent components: (a) a set of sensors that run on the site CE and worker nodes and update a database, (b) a simple yet extensible web services framework and (c) an Ajax powered web interface having a look-and-feel and control similar to a desktop application. The monitoring framework supports LSF, Condor and PBS-like batch systems. This is one of the first monitoring systems where an X.509 authenticated web interface can be seamlessly accessed by both end-users and site administrators. While a site administrator has access to all the possible information, a user can only view the jobs for the Virtual Organizations (VO) he/she is a part of. The monitoring framework design supports several possible deployment scenarios. For a site running a supported batch system, the system may be deployed as a whole, or existing site sensors can be adapted and reused with the web services components. A site may even prefer to build the web server independently and choose to use only the Ajax powered web interface. Finally, the system is being used to monitor a glideinWMS instance. This broadens the scope significantly, allowing it to monitor jobs over multiple sites.

A new approach for structural health monitoring by applying anomaly detection on strain sensor data

Science.gov (United States)

Trichias, Konstantinos; Pijpers, Richard; Meeuwissen, Erik

2014-03-01

Structural Health Monitoring (SHM) systems help to monitor critical infrastructures (bridges, tunnels, etc.) remotely and provide up-to-date information about their physical condition. In addition, it helps to predict the structure's life and required maintenance in a cost-efficient way. Typically, inspection data gives insight in the structural health. The global structural behavior, and predominantly the structural loading, is generally measured with vibration and strain sensors. Acoustic emission sensors are more and more used for measuring global crack activity near critical locations. In this paper, we present a procedure for local structural health monitoring by applying Anomaly Detection (AD) on strain sensor data for sensors that are applied in expected crack path. Sensor data is analyzed by automatic anomaly detection in order to find crack activity at an early stage. This approach targets the monitoring of critical structural locations, such as welds, near which strain sensors can be applied during construction and/or locations with limited inspection possibilities during structural operation. We investigate several anomaly detection techniques to detect changes in statistical properties, indicating structural degradation. The most effective one is a novel polynomial fitting technique, which tracks slow changes in sensor data. Our approach has been tested on a representative test structure (bridge deck) in a lab environment, under constant and variable amplitude fatigue loading. In both cases, the evolving cracks at the monitored locations were successfully detected, autonomously, by our AD monitoring tool.

The CUORE slow monitoring systems

Science.gov (United States)

Gladstone, L.; Biare, D.; Cappelli, L.; Cushman, J. S.; Del Corso, F.; Fujikawa, B. K.; Hickerson, K. P.; Moggi, N.; Pagliarone, C. E.; Schmidt, B.; Wagaarachchi, S. L.; Welliver, B.; Winslow, L. A.

2017-09-01

CUORE is a cryogenic experiment searching primarily for neutrinoless double decay in 130Te. It will begin data-taking operations in 2016. To monitor the cryostat and detector during commissioning and data taking, we have designed and developed Slow Monitoring systems. In addition to real-time systems using LabVIEW, we have an alarm, analysis, and archiving website that uses MongoDB, AngularJS, and Bootstrap software. These modern, state of the art software packages make the monitoring system transparent, easily maintainable, and accessible on many platforms including mobile devices.

An intelligent fetal monitoring system

International Nuclear Information System (INIS)

Inaba, J.; Akatsuka, T.; Kubo, T.; Iwasaki, H.

1986-01-01

An intelligent monitoring system is constructed by a multi-micro-computer system. The monitoring signals are fetal heart rate (FHR) and uterine contraction (UC) through the conventional monitoring device for a day until the delivery. These signals are fed to a micro-computer in digital format, and evaluated by the computer in real time according to the diagnostic algorithm of the expert physician. Monitoring signals are always displayed on the CRT screen and in the case of dangerous state of the fetus, warning signal will appear on the screen and the doctor or nurse will be called. All these signals are sent to the next micro-computer with 10MB hard disk system. On this computer, the doctor and nurse can retrieve and inspect the details of the process by clock-key and/or events-key. After finishing monitoring process, summarized report is constructed and printed out on the paper

Distributed Monitoring System Based on ICINGA

CERN Multimedia

Haen, C; Neufeld, N

2011-01-01

The LHCb online system relies on a large and heterogeneous I.T. infrastructure : it comprises more than 2000 servers and embedded systems and more than 200 network devices. While for the control and monitoring of detectors, PLCs, and readout boards an industry standard SCADA system PVSSII has been put in production, we use a low level monitoring system to monitor the control infrastructure itself. While our previous system was based on a single central NAGIOS server, our current system uses a distributed ICINGA infrastructure.

GTA Beamloss-Monitor System

International Nuclear Information System (INIS)

Rose, C.R.; Fortgang, C.M.; Power, J.P.

1992-01-01

The GTA Beamless-Monitor System at Los Alamos National Laboratory has been designed to detect high-energy particle loss in the accelerator beamline and shut down the accelerator before any damage can occur. To do this, the Beamless-Monitor System measures the induced gamma radiation, from (p, γ) reactions, at 15 selected points along the beamline, converts this measured radiation to electrical signals integrates and compares them to preset limits, and, in the event of an over-limit condition causes the Fast-Protect System to shut down the entire accelerator. The system dynamic range exceeds 70 dB which will enable experimenters to use the Beamless-Monitor System to help steer the beam as well as provide signals for a Fast-Protect System. The system response time is less than 7 μs assuming a step-function, worst-case beam spill of 50 mA. The system resolution, based on the noise floor of the electronics is about 1.3 mRads/s. Production units have been built and meet the above specifications. The remainder of the system will be installed and tested later in 1992/1993 with the GTA accelerator. The ionization chamber sensitivity and response time are described in the paper

GTA beamloss-monitor system

International Nuclear Information System (INIS)

Rose, C.R.; Fortgang, C.M.; Power, J.P.

1992-01-01

The GTA Beamloss-Monitor System at Los Alamos National Laboratory has been designed to detect high-energy particle loss in the accelerator beamline and shut down the accelerator before any damage can occur. To do this, the Beamloss-Monitor System measures the induced gamma radiation, from (p,γ) reactions, at 15 selected points along the beamline, converts this measured radiation to electrical signals, integrates and compares them to preset limits, and, in the event of an over-limit condition causes the Fast-Protect System to shut down the entire accelerator. The system dynamic range exceeds 70 dB which will enable experimenters to use the Beamloss-Monitor System to help steer the beam as well as provide signals for a Fast-Protect System. The system response time is less than 7 μs assuming a step-function, worst-case beam spill of 50 mA. The system resolution, based on the noise floor of the electronics, is about 1.3 mRads/s. Production units have been built and meet the above specifications. The remainder of the system will be installed and tested later in 1992/93 with the GTA accelerator. The ionization chamber sensitivity and response time are described in the paper. (Author) 4 figs., ref

Offsite emergency radiological monitoring system and technology

International Nuclear Information System (INIS)

Mao Yongze

1994-01-01

The study and advance of the offsite radiological monitoring system and technology which is an important branch in the field of nuclear monitoring technology are described. The author suggests that the predicting and measuring system should be involved in the monitoring system. The measuring system can further be divided into four sub-systems, namely plume exposure pathway, emergency worker, ingestion exposure pathway and post accident recovery measuring sub-systems. The main facilities for the monitoring system are concluded as one station, one helicopter, one laboratory and two vehicles. The instrumentation for complement of the facilities and their good performance characteristics, up-to-date technology are also introduced in brief. The offsite emergency radiation monitoring system and technology are compared in detail with those recommended by FEMA U.S.A.. Finally the paper discusses some trends in development of emergency radiation monitoring system and technology in the developed countries

System specification for the integrated monitoring and surveillance system

International Nuclear Information System (INIS)

1997-09-01

This System Specification establishes the requirements for the Plutonium Focus Area (PFA) Integrated Monitoring and Surveillance System (IMSS). In this document, ''Integrated Monitoring and Surveillance System'' is used to describe the concept of integrated sensors, computers, personnel, and systems that perform the functions of sensing conditions, acquiring data, monitoring environmental safety and health, controlling and accounting for materials, monitoring material stability, monitoring container integrity, transferring data, and analyzing, reporting, and storing data. This concept encompasses systems (e.g. sensors, personnel, databases, etc.) that are already in place at the sites but may require modifications or additions to meet all identified surveillance requirements. The purpose of this System Specification is to provide Department of Energy (DOE) sites that store plutonium materials with a consolidation of all known requirements for the storage and surveillance of 3013 packages of stabilized plutonium metals and oxides. This compilation may be used (1) as a baseline for surveillance system design specifications where 3013 packages of stabilized plutonium metals and oxides will be stored and monitored; (2) as a checklist for evaluating existing surveillance systems to ensure that all requirements are met for the storage and surveillance of 3013 packages of stabilized plutonium metals and oxides; and (3) as a baseline for preparing procurement specifications tailored for site specific storage and surveillance of 3013 packages of stabilized plutonium metals and oxides

Structural Health Monitoring System Trade Space Analysis Tool with Consideration for Crack Growth, Sensor Degradation and a Variable Detection Threshold

Science.gov (United States)

2014-09-18

Fatigue crack growth ..................................................................................................25 Probability of detection...32 Figure 5: Fatigue crack growth simulation results for 10 runs .............................................. 35 Figure 6...43 Figure 10: Linear regression fit of ln() vs. ln( ) data for SHM using PZT sensors (Kuhn, 2009

ERMS - Environmental Radiation Monitoring System

International Nuclear Information System (INIS)

Vax, Eran; Sarusi, Benny; Sheinfeld, Mati; Levinson, Shmuel; Brandys, Irad; Sattinger, Danny; Wengrowicz, Udi; Tshuva, Avi; Tirosh, Dan

2008-01-01

A new Environmental Radiation Monitoring System (ERMS) has been developed in the NRCN as an extensive tool to be applied in case of nuclear malfunction or Nuclear Disposal Device (NDD) incident, as well as for routine radiation monitoring of the reactor's vicinity. The system collects real-time environmental data such as: gamma radiation, wind speed, wind direction, and temperature for monitoring purposes. The ERMS consists of a main Control Center and an array of monitoring stations. Fixed, environmental, gamma radiation monitoring stations are installed at the reactor's surroundings while portable stations can be posted rapidly along the wind direction, enhancing the spatial sampling of the radiation measurements and providing better hazard assessment at an emergency event. The presented ERMS, based on industrial standards for hardware and network protocols, is a reliable standalone system which upgrades the readiness to face a nuclear emergency event by supplying real-time, integrated meteorological and radiation data. (author)

The Pajarito Monitor: a high-sensitivity monitoring system for highly enriched uranium

International Nuclear Information System (INIS)

Fehlau, P.E.; Coop, K.; Garcia, C.; Martinez, J.

1984-01-01

The Pajarito Monitor for Special Nuclear Material is a high-sensitivity gamma-ray monitoring system for detecting small quantities of highly enriched uranium transported by pedestrians or motor vehicles. The monitor consists of two components: a walk-through personnel monitor and a vehicle monitor. The personnel monitor has a plastic-scintillator detector portal, a microwave occupancy monitor, and a microprocessor control unit that measures the radiation intensity during background and monitoring periods to detect transient diversion signals. The vehicle monitor examines stationary motor vehicles while the vehicle's occupants pass through the personnel portal to exchange their badges. The vehicle monitor has four groups of large plastic scintillators that scan the vehicle from above and below. Its microprocessor control unit measures separate radiation intensities in each detector group. Vehicle occupancy is sensed by a highway traffic detection system. Each monitor's controller is responsible for detecting diversion as well as serving as a calibration and trouble-shooting aid. Diversion signals are detected by a sequential probability ratio hypothesis test that minimizes the monitoring time in the vehicle monitor and adapts itself well to variations in individual passage speed in the personnel monitor. Designed to be highly sensitive to diverted enriched uranium, the monitoring system also exhibits exceptional sensitivity for plutonium

Energy Doubler cryoloop temperature monitor system

International Nuclear Information System (INIS)

Pucci, G.; Howard, D.

1981-10-01

The Cryoloop Temperature Monitor System is a fully electronic system designed to monitor temperature at key points in the Energy Doubler cryoloop system. It is used for cryoloop diagnostics, temperature studies, and cooldown valve control

Hanger-type laundry monitor system

International Nuclear Information System (INIS)

Aoyama, Kei; Kouno, Yoshio; Yanagishima, Ryouhei; Ikeda, Yasuyuki; Nakatani, Masahiro

1987-01-01

Laundry monitor is installed in nuclear power plants or other nuclear facilities in order to efficiently detect radioactive contamination remains on the surfaces of the working clothes which were used in the controlled area and washed afterward. The number of the working clothes which must be measured has been increasing in accordance with the increase of the nuclear facilities. This fact and recent intensified radiation control require automatic, high-speed and high sensitive measurement. Conveyer-type laundry monitor in which the working clothes are inserted by the metal net conveyer has been generally used, and recently new system with an automatic folder has become more popular. But, this type of system has not so big capacity because the clothes are conveyed longitudinally and also requires considerable wide space when installed. Fuji electric Co., Ltd. has been engaging in research and development for an optimum laundry monitor system used in nuclear facilities since the joint investigation with ten electric power companies in Japan in 1982. Consequently hanger-type laundry monitor system using automatic hanger conveyer was developed and 2 systems were delivered to Chubu Electric Power Co., Ltd. in 1986. This system permits to detect radioactive contamination on the working clothes, pick the contaminated clothes out and fold the uncontaminated clothes fully automatically and continuously. Moreover it allows to shorten the measurement time because the clothes are conveyed transversely and save the installation space, so that this will be regarded as considerably complete system in the world. This report describes the outline of the hanger-type laundry monitor system. (author)

Storage monitoring systems for the year 2000

International Nuclear Information System (INIS)

Nilsen, C.; Pollock, R.

1997-01-01

In September 1993, President Clinton stated the US would ensure that its fissile material meet the highest standards of safety, security, and international accountability. Frequent human inspection of the material could be used to ensure these standards. However, it may be more effective and less expensive to replace these manual inspections with virtual inspections via remote monitoring technologies. To prepare for this future, Sandia National Laboratories has developed several monitoring systems, including the Modular Integrated Monitoring System (MIMS) and Project Straight-Line. The purpose of this paper is to describe a Sandia effort that merges remote monitoring technologies into a comprehensive storage monitoring system that will meet the near-term as well as the long-term requirements for these types of systems. Topics discussed include: motivations for storage monitoring systems to include remote monitoring; an overview of the needs and challenges of providing a storage monitoring system for the year 2000; an overview of how the MIMS and Straight-Line can be enhanced so that together they create an integrated and synergistic information system by the end of 1997; and suggested milestones for 1998 and 1999 to assure steady progress in preparing for the needs of 2000

Performance Monitoring Applied to System Supervision

Directory of Open Access Journals (Sweden)

Bertille Somon

2017-07-01

Full Text Available Nowadays, automation is present in every aspect of our daily life and has some benefits. Nonetheless, empirical data suggest that traditional automation has many negative performance and safety consequences as it changed task performers into task supervisors. In this context, we propose to use recent insights into the anatomical and neurophysiological substrates of action monitoring in humans, to help further characterize performance monitoring during system supervision. Error monitoring is critical for humans to learn from the consequences of their actions. A wide variety of studies have shown that the error monitoring system is involved not only in our own errors, but also in the errors of others. We hypothesize that the neurobiological correlates of the self-performance monitoring activity can be applied to system supervision. At a larger scale, a better understanding of system supervision may allow its negative effects to be anticipated or even countered. This review is divided into three main parts. First, we assess the neurophysiological correlates of self-performance monitoring and their characteristics during error execution. Then, we extend these results to include performance monitoring and error observation of others or of systems. Finally, we provide further directions in the study of system supervision and assess the limits preventing us from studying a well-known phenomenon: the Out-Of-the-Loop (OOL performance problem.

Plant-wide integrated equipment monitoring and analysis system

International Nuclear Information System (INIS)

Morimoto, C.N.; Hunter, T.A.; Chiang, S.C.

2004-01-01

A nuclear power plant equipment monitoring system monitors plant equipment and reports deteriorating equipment conditions. The more advanced equipment monitoring systems can also provide information for understanding the symptoms and diagnosing the root cause of a problem. Maximizing the equipment availability and minimizing or eliminating consequential damages are the ultimate goals of equipment monitoring systems. GE Integrated Equipment Monitoring System (GEIEMS) is designed as an integrated intelligent monitoring and analysis system for plant-wide application for BWR plants. This approach reduces system maintenance efforts and equipment monitoring costs and provides information for integrated planning. This paper describes GEIEMS and how the current system is being upgraded to meet General Electric's vision for plant-wide decision support. (author)

Benzene Monitor System report

International Nuclear Information System (INIS)

Livingston, R.R.

1992-01-01

Two systems for monitoring benzene in aqueous streams have been designed and assembled by the Savannah River Technology Center, Analytical Development Section (ADS). These systems were used at TNX to support sampling studies of the full-scale open-quotes SRAT/SME/PRclose quotes and to provide real-time measurements of benzene in Precipitate Hydrolysis Aqueous (PHA) simulant. This report describes the two ADS Benzene Monitor System (BMS) configurations, provides data on system operation, and reviews the results of scoping tests conducted at TNX. These scoping tests will allow comparison with other benzene measurement options being considered for use in the Defense Waste Processing Facility (DWPF) laboratory. A report detailing the preferred BMS configuration statistical performance during recent tests has been issued under separate title: Statistical Analyses of the At-line Benzene Monitor Study, SCS-ASG-92-066. The current BMS design, called the At-line Benzene Monitor (ALBM), allows remote measurement of benzene in PHA solutions. The authors have demonstrated the ability to calibrate and operate this system using peanut vials from a standard Hydragard trademark sampler. The equipment and materials used to construct the ALBM are similar to those already used in other applications by the DWPF lab. The precision of this system (±0.5% Relative Standard Deviation (RSD) at 1 sigma) is better than the purge ampersand trap-gas chromatograpy reference method currently in use. Both BMSs provide a direct measurement of the benzene that can be purged from a solution with no sample pretreatment. Each analysis requires about five minutes per sample, and the system operation requires no special skills or training. The analyzer's computer software can be tailored to provide desired outputs. Use of this system produces no waste stream other than the samples themselves (i.e. no organic extractants)

On predicting monitoring system effectiveness

Science.gov (United States)

Cappello, Carlo; Sigurdardottir, Dorotea; Glisic, Branko; Zonta, Daniele; Pozzi, Matteo

2015-03-01

While the objective of structural design is to achieve stability with an appropriate level of reliability, the design of systems for structural health monitoring is performed to identify a configuration that enables acquisition of data with an appropriate level of accuracy in order to understand the performance of a structure or its condition state. However, a rational standardized approach for monitoring system design is not fully available. Hence, when engineers design a monitoring system, their approach is often heuristic with performance evaluation based on experience, rather than on quantitative analysis. In this contribution, we propose a probabilistic model for the estimation of monitoring system effectiveness based on information available in prior condition, i.e. before acquiring empirical data. The presented model is developed considering the analogy between structural design and monitoring system design. We assume that the effectiveness can be evaluated based on the prediction of the posterior variance or covariance matrix of the state parameters, which we assume to be defined in a continuous space. Since the empirical measurements are not available in prior condition, the estimation of the posterior variance or covariance matrix is performed considering the measurements as a stochastic variable. Moreover, the model takes into account the effects of nuisance parameters, which are stochastic parameters that affect the observations but cannot be estimated using monitoring data. Finally, we present an application of the proposed model to a real structure. The results show how the model enables engineers to predict whether a sensor configuration satisfies the required performance.

Monitoring in educational development projects : the development of a monitoring system

NARCIS (Netherlands)

Plomp, T.; Huijsman, Hari; Kluyfhout, Eric

1992-01-01

Monitoring in education is usually focused on the monitoring of educational systems at different levels. Monitoring of educational projects receives only recently explicit attention. The paper discusses first the concepts of educational monitoring and evaluation. After that, the experience with

CERN GSM monitoring system

CERN Multimedia

Ghabrous Larrea, C

2009-01-01

As a result of the tremendous development of GSM services over the last years, the number of related services used by organizations has drastically increased. Therefore, monitoring GSM services is becoming a business critical issue in order to be able to react appropriately in case of incident. In order to provide with GSM coverage all the CERN underground facilities, more than 50 km of leaky feeder cable have been deployed. This infrastructure is also used to propagate VHF radio signals for the CERN’s fire brigade. Even though CERN’s mobile operator monitors the network, it cannot guarantee the availability of GSM services, and for sure not VHF services, where signals are carried by the leaky feeder cable. So, a global monitoring system has become critical to CERN. In addition, monitoring this infrastructure will allow to characterize its behaviour over time, especially with LHC operation. Given that commercial solutions were not yet mature, CERN developed a system based on GSM probes and an application...

Remote supervision of GIS monitoring system

Energy Technology Data Exchange (ETDEWEB)

Pannunzio, J.; Juge, P.; Ficheux, A.; Rayon, J.L. [Areva T and D Automation Canada Inc., Monteal, PQ (Canada)

2007-07-01

Operators of gas-insulated substations (GIS) are increasingly concerned with failure prevention, scheduled maintenance, personnel safety and shortage of maintenance crews. Until recently, the density levels of the insulating gas sulfur hexafluoride (SF6) was the only parameter controlled in gas-insulated substations. Modern digital type control and monitoring equipment have been widely used in the past decade. Remote indication of gas density and status of dynamic components was made possible and shown on local control panels. Modern GIS monitoring systems offer features such as SF6 monitoring, SF6 leakage trends, internal arc localization and detection. The required information is recorded in a local computer and displaced onto a local human machine interface (HMI) or a local industrial PC mounted next to the GIS. These monitoring systems are used as decision making tools to facilitate maintenance activities and optimize the management of assets. This paper presented the latest developments in digital monitoring systems in terms of modern digital architecture; management of information flows between monitoring systems and control systems; operation of remote supervision; configuration of high voltage substations and information sharing; and, types of links between GIS room and remote supervision. This paper also demonstrated what can be achieved by moving the central HMI of a GIS monitoring system to the decision-making centres. It was shown that integrated features that allow remote on-line or automated management have reached an acceptable level of reliability and comfort for operators. 5 figs.

System of message for gamma-radiation monitor

International Nuclear Information System (INIS)

Bolic, M.D.; Koturovic, A.M.

2001-01-01

Paper describes a system of voice messages for gamma-radiation monitor based on PC. The systems reproduces recorded messages that is simpler than the process of their synthesis. Message choice is based on combination of recorded digital results and/or received reference messages or warnings. The system of generation of voice messages applies the Windows based software. The total memory array required to create independent voice system is maximum 1.7 mbyte. The monitor may be used for continuous monitoring of radioactivity level with 5-8 s period of message repetition. Another option of the system operation is based on monitor application for the environment monitoring. Period of messages in this case is equal to 5-30 min [ru

Implementation of a compressive sampling scheme for wireless sensors to achieve energy efficiency in a structural health monitoring system

Science.gov (United States)

O'Connor, Sean M.; Lynch, Jerome P.; Gilbert, Anna C.

2013-04-01

Wireless sensors have emerged to offer low-cost sensors with impressive functionality (e.g., data acquisition, computing, and communication) and modular installations. Such advantages enable higher nodal densities than tethered systems resulting in increased spatial resolution of the monitoring system. However, high nodal density comes at a cost as huge amounts of data are generated, weighing heavy on power sources, transmission bandwidth, and data management requirements, often making data compression necessary. The traditional compression paradigm consists of high rate (>Nyquist) uniform sampling and storage of the entire target signal followed by some desired compression scheme prior to transmission. The recently proposed compressed sensing (CS) framework combines the acquisition and compression stage together, thus removing the need for storage and operation of the full target signal prior to transmission. The effectiveness of the CS approach hinges on the presence of a sparse representation of the target signal in a known basis, similarly exploited by several traditional compressive sensing applications today (e.g., imaging, MRI). Field implementations of CS schemes in wireless SHM systems have been challenging due to the lack of commercially available sensing units capable of sampling methods (e.g., random) consistent with the compressed sensing framework, often moving evaluation of CS techniques to simulation and post-processing. The research presented here describes implementation of a CS sampling scheme to the Narada wireless sensing node and the energy efficiencies observed in the deployed sensors. Of interest in this study is the compressibility of acceleration response signals collected from a multi-girder steel-concrete composite bridge. The study shows the benefit of CS in reducing data requirements while ensuring data analysis on compressed data remain accurate.

Signal-based nonlinear modelling for damage assessment under variable temperature conditions by means of acousto-ultrasonics

DEFF Research Database (Denmark)

Torres-Arredondo, M. -A.; Sierra-Perez, Julian; Tibaduiza, D. -A.

2015-01-01

Damage assessment can be considered as the main task within the context of structural health monitoring (SHM) systems. This task is not only confined to the detection of damages in its basic algorithms but also in the generation of early warnings to prevent possible catastrophes in the daily use...

Stack Monitoring System At PUSPATI TRIGA Reactor

International Nuclear Information System (INIS)

Zamrul Faizad Omar; Mohd Sabri Minhat; Zareen Khan Abdul Jalil Khan; Ridzuan Abdul Mutalib; Khairulezwan Abdul Manan; Nurfarhana Ayuni Joha; Izhar Abu Hussin

2014-01-01

This paper describes the current Stack Monitoring System at PUSPATI TRIGA Reactor (RTP) building. A stack monitoring system is a continuous air monitor placed at the reactor top for monitoring the presence of radioactive gaseous in the effluent air from the RTP building. The system consists of four detectors that provide the reading for background, particulate, Iodine and Noble gas. There is a plan to replace the current system due to frequent fault of the system, thus thorough understanding of the current system is required. Overview of the whole system will be explained in this paper. Some current results would be displayed and moving forward brief plan would be mentioned. (author)

Digital radiation monitor system

International Nuclear Information System (INIS)

Quan Jinhu; Zhai Yongchun; Guan Junfeng; Ren Dangpei; Ma Zhiyuan

2003-01-01

The article introduced digital radiation monitor system. The contents include: how to use advanced computer net technology to establish equipment net for nuclear facility, how to control and manage measuring instruments on field equipment net by local area net, how to manage and issue radiation monitoring data by internet

Instrumentation for Power System Disturbance Monitoring, Data ...

African Journals Online (AJOL)

In this paper, the level of instrumentation for power system disturbance monitoring, data acquisition and control in Nigerian Electric Power System; National Electric Power Authority (NEPA) is presented. The need for accurate power system disturbance monitoring is highlighted. A feature of an adequate monitoring, data ...

Fundamental and assessment of concrete structure monitoring by using acoustic emission technique testing: A review

Science.gov (United States)

Desa, M. S. M.; Ibrahim, M. H. W.; Shahidan, S.; Ghadzali, N. S.; Misri, Z.

2018-04-01

Acoustic emission (AE) technique is one of the non-destructive (NDT) testing, where it can be used to determine the damage of concrete structures such as crack, corrosion, stability, sensitivity, as structure monitoring and energy formed within cracking opening growth in the concrete structure. This article gives a comprehensive review of the acoustic emission (AE) technique testing due to its application in concrete structure for structural health monitoring (SHM). Assessment of AE technique used for structural are reviewed to give the perception of its structural engineering such as dam, bridge and building, where the previous research has been reviewed based on AE application. The assessment of AE technique focusing on basic fundamental of parametric and signal waveform analysis during analysis process and its capability in structural monitoring. Moreover, the assessment and application of AE due to its function have been summarized and highlighted for future references

A unique radiation area monitoring system

International Nuclear Information System (INIS)

Murphy, P.C.; Allen, G.C.

1978-01-01

The Remote Area Monitoring Systems (RAMS) monitors four radiation areas with two independent systems in each area. Each system consists of power supplies, four ionization chambers, and four analog and digital circuits. The first system controls the warning beacons, horns, annunciation panel and interlocks. The second system presents a quantitative dose rate indication at the console and in the radiation area

Fatigue crack detection and identification by the elastic wave propagation method

Science.gov (United States)

Stawiarski, Adam; Barski, Marek; Pająk, Piotr

2017-05-01

In this paper the elastic wave propagation phenomenon was used to detect the initiation of the fatigue damage in isotropic plate with a circular hole. The safety and reliability of structures mostly depend on the effectiveness of the monitoring methods. The Structural Health Monitoring (SHM) system based on the active pitch-catch measurement technique was proposed. The piezoelectric (PZT) elements was used as an actuators and sensors in the multipoint measuring system. The comparison of the intact and defected structures has been used by damage detection algorithm. One part of the SHM system has been responsible for detection of the fatigue crack initiation. The second part observed the evolution of the damage growth and assess the size of the defect. The numerical results of the wave propagation phenomenon has been used to present the effectiveness and accuracy of the proposed method. The preliminary experimental analysis has been carried out during the tension test of the aluminum plate with a circular hole to determine the efficiency of the measurement technique.

Remote Arrhythmia Monitoring System Developed

Science.gov (United States)

York, David W.; Mackin, Michael A.; Liszka, Kathy J.; Lichter, Michael J.

2004-01-01

Telemedicine is taking a step forward with the efforts of team members from the NASA Glenn Research Center, the MetroHealth campus of Case Western University, and the University of Akron. The Arrhythmia Monitoring System is a completed, working test bed developed at Glenn that collects real-time electrocardiogram (ECG) signals from a mobile or homebound patient, combines these signals with global positioning system (GPS) location data, and transmits them to a remote station for display and monitoring. Approximately 300,000 Americans die every year from sudden heart attacks, which are arrhythmia cases. However, not all patients identified at risk for arrhythmias can be monitored continuously because of technological and economical limitations. Such patients, who are at moderate risk of arrhythmias, would benefit from technology that would permit long-term continuous monitoring of electrical cardiac rhythms outside the hospital environment. Embedded Web Technology developed at Glenn to remotely command and collect data from embedded systems using Web technology is the catalyst for this new telemetry system (ref. 1). In the end-to-end system architecture, ECG signals are collected from a patient using an event recorder and are transmitted to a handheld personal digital assistant (PDA) using Bluetooth, a short-range wireless technology. The PDA concurrently tracks the patient's location via a connection to a GPS receiver. A long distance link is established via a standard Internet connection over a 2.5-generation Global System for Mobile Communications/General Packet Radio Service (GSM/GPRS)1 cellular, wireless infrastructure. Then, the digital signal is transmitted to a call center for monitoring by medical professionals.

Drinking-water monitoring systems

International Nuclear Information System (INIS)

1994-01-01

A new measuring system was developed by the Austrian Research Centre Seibersdorf for monitoring the quality of drinking-water. It is based on the experience made with the installation of UWEDAT (registered trademark) environmental monitoring networks in several Austrian provinces and regions. The standard version of the drinking-water monitoring system comprises sensors for measuring chemical parameters in water, radioactivity in water and air, and meteorological values of the environment. Further measuring gauges, e.g. for air pollutants, can be connected at any time, according to customers' requirements. For integration into regional and supraregional networks, station computers take over the following tasks: Collection of data and status signals transmitted by the subsystem, object protection, intermediate storage and communication of data to the host or several subcentres via Datex-P postal service, permanent lines or radiotransmission

Surveillance systems (PWR) - loose parts monitoring - vibration monitoring - leakage detection

International Nuclear Information System (INIS)

Schuette, A.; Blaesig, H.

1982-01-01

The contribution is engaged in the task and the results of the loose parts monitoring and the vibration monitoring following from the practice at the PWR of Biblis. First a description of both systems - location and type of the sensors used, the treatment of the measurements and the indications - is given. The results of the analysis of some events picked up by the surveillance systems are presented showing applicabilty and benefit of such systems. (orig.)

Damage Identification of Wind Turbine Blades Using Piezoelectric Transducers

Directory of Open Access Journals (Sweden)

Seong-Won Choi

2014-01-01

Full Text Available This paper presents the experimental results of active-sensing structural health monitoring (SHM techniques, which utilize piezoelectric transducers as sensors and actuators, for determining the structural integrity of wind turbine blades. Specifically, Lamb wave propagations and frequency response functions at high frequency ranges are used to estimate the condition of wind turbine blades. For experiments, a 1 m section of a CX-100 blade is used. The goal of this study is to assess and compare the performance of each method in identifying incipient damage with a consideration given to field deployability. Overall, these methods yielded a sufficient damage detection capability to warrant further investigation. This paper also summarizes the SHM results of a full-scale fatigue test of a 9 m CX-100 blade using piezoelectric active sensors. This paper outlines considerations needed to design such SHM systems, experimental procedures and results, and additional issues that can be used as guidelines for future investigations.

Car monitoring information systems

Directory of Open Access Journals (Sweden)

Alica KALAŠOVÁ

2008-01-01

Full Text Available The objective of this contribution is to characterize alternatives of information systems used for managing, processing and evaluation of information related to company vehicles. Especially we focus on logging, transferring and processing of on-road vehicle movement information in inland and international transportation. This segment of company information system has to monitor the car movement – actively or passively – according to demand of the company and after the processing it has to evaluate and give the complex monitoring of a situation of all the company vehicles to the controller.

Remote container monitoring and surveillance systems

International Nuclear Information System (INIS)

Resnik, W.M.; Kadner, S.P.

1995-01-01

Aquila Technologies Group is developing a monitoring and surveillance system to monitor containers of nuclear materials. The system will both visually and physically monitor the containers. The system is based on the combination of Aquila's Gemini All-Digital Surveillance System and on Aquila's AssetLAN trademark asset tracking technology. This paper discusses the Gemini Digital Surveillance system as well as AssetLAN technology. The Gemini architecture with emphasis on anti-tamper security features is also described. The importance of all-digital surveillance versus other surveillance methods is also discussed. AssetLAN trademark technology is described, emphasizing the ability to continually track containers (as assets) by location utilizing touch memory technology. Touch memory technology provides unique container identification, as well as the ability to store and retrieve digital information on the container. This information may relate to container maintenance, inspection schedules, and other information. Finally, this paper describes the combination of the Gemini system with AssetLAN technology, yielding a self contained, container monitoring and area/container surveillance system. Secure container fixture design considerations are discussed. Basic surveillance review functions are also discussed

Critical function monitoring system algorithm development

International Nuclear Information System (INIS)

Harmon, D.L.

1984-01-01

Accurate critical function status information is a key to operator decision-making during events threatening nuclear power plant safety. The Critical Function Monitoring System provides continuous critical function status monitoring by use of algorithms which mathematically represent the processes by which an operating staff would determine critical function status. This paper discusses in detail the systematic design methodology employed to develop adequate Critical Function Monitoring System algorithms

Centralized environmental radiation monitoring system in JAERI

International Nuclear Information System (INIS)

Katagiri, Hiroshi; Kobayashi, Hideo

1993-03-01

Japan Atomic Energy Research Institute (JAERI) has continued the radiation background survey and environmental radiation monitoring to ensure the safety of the residents around the Institute. For the monitoring of β and γ radiations and α and β radioactivities in air, the centralized automatic environmental radiation monitoring system (EMS) applying a computer with monitoring stations (MS) was established. The system has been renewed twice in 1973 and 1988. In 1962, a new concept emergency environmental γ-ray monitoring system (MP) was begun to construct and completed in 1965 independent of EMS. The first renewal of the EMS was carried out by focusing on the rapid and synthetic judgement and estimation of the environmental impacts caused by radiation and radioactive materials due to the operation of nuclear facilities by centralizing the data measured at MS, MP, a meteorological station, stack monitors and drainage monitoring stations under the control of computer. Present system renewed in 1988 was designed to prevent the interruption of monitoring due to computer troubles, communication troubles and power failures especially an instant voltage drop caused by thunder by reflecting the experiences through the operation and maintenance of the former system. Dual telemeters whose power is constantly supplied via batteries (capable of 10 min. monitoring after power failure) are equipped in the monitoring center to cope with telemeter troubles, which has operated successfully without any suspension being attributable to the power failures and telemeter troubles. (J.P.N.)

Impedance-based structural health monitoring of additive manufactured structures with embedded piezoelectric wafers

Science.gov (United States)

Scheyer, Austin G.; Anton, Steven R.

2017-04-01

Embedding sensors within additive manufactured (AM) structures gives the ability to develop smart structures that are capable of monitoring the mechanical health of a system. AM provides an opportunity to embed sensors within a structure during the manufacturing process. One major limitation of AM technology is the ability to verify the geometric and material properties of fabricated structures. Over the past several years, the electromechanical impedance (EMI) method for structural health monitoring (SHM) has been proven to be an effective method for sensing damage in structurers. The EMI method utilizes the coupling between the electrical and mechanical properties of a piezoelectric transducer to detect a change in the dynamic response of a structure. A piezoelectric device, usually a lead zirconate titanate (PZT) ceramic wafer, is bonded to a structure and the electrical impedance is measured across as range of frequencies. A change in the electrical impedance is directly correlated to changes made to the mechanical condition of the structure. In this work, the EMI method is employed on piezoelectric transducers embedded inside AM parts to evaluate the feasibility of performing SHM on parts fabricated using additive manufacturing. The fused deposition modeling (FDM) method is used to print specimens for this feasibility study. The specimens are printed from polylactic acid (PLA) in the shape of a beam with an embedded monolithic piezoelectric ceramic disc. The specimen is mounted as a cantilever while impedance measurements are taken using an HP 4194A impedance analyzer. Both destructive and nondestructive damage is simulated in the specimens by adding an end mass and drilling a hole near the free end of the cantilever, respectively. The Root Mean Square Deviation (RMSD) method is utilized as a metric for quantifying damage to the system. In an effort to determine a threshold for RMSD, the values are calculated for the variation associated with taking multiple

Distributed intelligent urban environment monitoring system

Science.gov (United States)

Du, Jinsong; Wang, Wei; Gao, Jie; Cong, Rigang

2018-02-01

The current environmental pollution and destruction have developed into a world-wide major social problem that threatens human survival and development. Environmental monitoring is the prerequisite and basis of environmental governance, but overall, the current environmental monitoring system is facing a series of problems. Based on the electrochemical sensor, this paper designs a small, low-cost, easy to layout urban environmental quality monitoring terminal, and multi-terminal constitutes a distributed network. The system has been small-scale demonstration applications and has confirmed that the system is suitable for large-scale promotion

A wireless laser displacement sensor node for structural health monitoring.

Science.gov (United States)

Park, Hyo Seon; Kim, Jong Moon; Choi, Se Woon; Kim, Yousok

2013-09-30

This study describes a wireless laser displacement sensor node that measures displacement as a representative damage index for structural health monitoring (SHM). The proposed measurement system consists of a laser displacement sensor (LDS) and a customized wireless sensor node. Wireless communication is enabled by a sensor node that consists of a sensor module, a code division multiple access (CDMA) communication module, a processor, and a power module. An LDS with a long measurement distance is chosen to increase field applicability. For a wireless sensor node driven by a battery, we use a power control module with a low-power processor, which facilitates switching between the sleep and active modes, thus maximizing the power consumption efficiency during non-measurement and non-transfer periods. The CDMA mode is also used to overcome the limitation of communication distance, which is a challenge for wireless sensor networks and wireless communication. To evaluate the reliability and field applicability of the proposed wireless displacement measurement system, the system is tested onsite to obtain the required vertical displacement measurements during the construction of mega-trusses and an edge truss, which are the primary structural members in a large-scale irregular building currently under construction. The measurement values confirm the validity of the proposed wireless displacement measurement system and its potential for use in safety evaluations of structural elements.

A Wireless Laser Displacement Sensor Node for Structural Health Monitoring

Directory of Open Access Journals (Sweden)

Se Woon Choi

2013-09-01

Full Text Available This study describes a wireless laser displacement sensor node that measures displacement as a representative damage index for structural health monitoring (SHM. The proposed measurement system consists of a laser displacement sensor (LDS and a customized wireless sensor node. Wireless communication is enabled by a sensor node that consists of a sensor module, a code division multiple access (CDMA communication module, a processor, and a power module. An LDS with a long measurement distance is chosen to increase field applicability. For a wireless sensor node driven by a battery, we use a power control module with a low-power processor, which facilitates switching between the sleep and active modes, thus maximizing the power consumption efficiency during non-measurement and non-transfer periods. The CDMA mode is also used to overcome the limitation of communication distance, which is a challenge for wireless sensor networks and wireless communication. To evaluate the reliability and field applicability of the proposed wireless displacement measurement system, the system is tested onsite to obtain the required vertical displacement measurements during the construction of mega-trusses and an edge truss, which are the primary structural members in a large-scale irregular building currently under construction. The measurement values confirm the validity of the proposed wireless displacement measurement system and its potential for use in safety evaluations of structural elements.

Visualization System for Monitoring Data Management Systems

Directory of Open Access Journals (Sweden)

Emanuel Pinho

2016-11-01

Full Text Available Usually, a Big Data system has a monitoring system for performance evaluation and error prevention. There are some disadvantages in the way that these tools display the information and its targeted approach to physical components. The main goal is to study visual and interactive mechanisms that allow the representation of monitoring data in grid computing environments, providing the end-user information, which can contribute objectively to the system analysis. This paper is an extension of the paper presented at (Pinho and Carvalho 2016 and has the purpose to present the state of the art, carries out the proposed solution and present the achieved goals.

Online NPP monitoring with neuro-expert system

International Nuclear Information System (INIS)

Nabeshima, K.

2002-01-01

This study present a hybrid monitoring system for nuclear power plant utilizing neural networks and a rule-based expert system. The whole monitoring system including a data acquisition system and the advisory displays has been tested by an on-line simulator of pressurized water reactor. From the testing results, it was shown that the neural network in the monitoring system successfully modeled the plant dynamics and detected the symptoms of anomalies earlier than the conventional alarm system. The expert system also worked satisfactorily in diagnosing and displaying the system status by using the outputs of neural networks and a priori knowledge base

Resilience of System by Value of Information and SHM

DEFF Research Database (Denmark)

Miragliaa, S.; Nielsen, Michael Havbro Faber; Thöns, S.

2017-01-01

infrastructure systems. In response to this challenge, the present contribution puts forwards a novel approach, taking basis in the concept of value of information analysis from Bayesian pre posterior decision analysis. Utilizing a principal model framework we show how the proposed approach is implemented...

Resilience of systems by value of information and SHM

DEFF Research Database (Denmark)

Miraglia, Simona; Faber, Michael H.; Thöns, Sebastian

2017-01-01

infrastructure systems. In response to this challenge, the present contribution puts forwards a novel approach, taking basis in the concept of value of information analysis from Bayesian pre-posterior decision analysis. Utilizing a principal model framework we show how the proposed approach is implemented...

Area monitoring intelligent system - SIMA

International Nuclear Information System (INIS)

Bhoem, P.; Hisas, F.; Gelardi, G.

1990-01-01

The area monitoring intelligent system (SIMA) is an equipment to be used in radioprotection. SIMA has the function of monitoring the radiation levels of determined areas of the installations where radioactive materials are handled. (Author) [es

Computerized plutonium laboratory-stack monitoring system

International Nuclear Information System (INIS)

Stafford, R.G.; DeVore, R.K.

1977-01-01

The Los Alamos Scientific Laboratory has recently designed and constructed a Plutonium Research and Development Facility to meet design criteria imposed by the United States Energy Research and Development Administration. A primary objective of the design criteria is to assure environmental protection and to reliably monitor plutonium effluent via the ventilation exhaust systems. A state-of-the-art facility exhaust air monitoring system is described which establishes near ideal conditions for evaluating plutonium activity in the stack effluent. Total and static pressure sensing manifolds are incorporated to measure average velocity and integrated total discharge air volume. These data are logged at a computer which receives instrument data through a multiplex scanning system. A multipoint isokinetic sampling assembly with associated instrumentation is described. Continuous air monitors have been designed to sample from the isokinetic sampling assembly and transmit both instantaneous and integrated stack effluent concentration data to the computer and various cathode ray tube displays. The continuous air monitors also serve as room air monitors in the plutonium facility with the primary objective of timely evacuation of personnel if an above tolerance airborne plutonium concentration is detected. Several continuous air monitors are incorporated in the ventilation system to assist in identification of release problem areas

An implementation of a data-transmission pipelining algorithm on Imote2 platforms

Science.gov (United States)

Li, Xu; Dorvash, Siavash; Cheng, Liang; Pakzad, Shamim

2011-04-01

Over the past several years, wireless network systems and sensing technologies have been developed significantly. This has resulted in the broad application of wireless sensor networks (WSNs) in many engineering fields and in particular structural health monitoring (SHM). The movement of traditional SHM toward the new generation of SHM, which utilizes WSNs, relies on the advantages of this new approach such as relatively low costs, ease of implementation and the capability of onboard data processing and management. In the particular case of long span bridge monitoring, a WSN should be capable of transmitting commands and measurement data over long network geometry in a reliable manner. While using single-hop data transmission in such geometry requires a long radio range and consequently a high level of power supply, multi-hop communication may offer an effective and reliable way for data transmissions across the network. Using a multi-hop communication protocol, the network relays data from a remote node to the base station via intermediary nodes. We have proposed a data-transmission pipelining algorithm to enable an effective use of the available bandwidth and minimize the energy consumption and the delay performance by the multi-hop communication protocol. This paper focuses on the implementation aspect of the pipelining algorithm on Imote2 platforms for SHM applications, describes its interaction with underlying routing protocols, and presents the solutions to various implementation issues of the proposed pipelining algorithm. Finally, the performance of the algorithm is evaluated based on the results of an experimental implementation.

Upgrade of the LHCb ECAL monitoring system

CERN Document Server

Guz, Yu

2015-01-01

The LHCb ECAL is a shashlik calorimeter of 6016 cells, covering 7.68 x 6.24 m$^2$ area. To monitor the readout chain of each ECAL cell, the LHCb ECAL is equipped with a LED based monitoring system. During the LHC Run I (2009-2012) it was found that the precision of the monitoring suffers from the radiation degradation of transparency of polystyrene clear fibers used to transport the LED light to the ECAL photomultipliers. In order to improve the performance of the monitoring system, and especially in view of significant increase of LHCb working luminosity foreseen after 2018, the present plastic fibers have been replaced by radiation hard quartzfi bers. The performance of the old LHCb ECAL monitoring system during LHC Run I and the design of the upgraded system are discussed here.

Centralized environmental radiation monitoring system in JAERI

International Nuclear Information System (INIS)

Katagiri, H.; Kobalyashi, H.

1993-01-01

JAERI has continued the environmental radiation background survey and monitoring to ensure the safety of the peoples around the institute since one year before the first criticality of JRR-1 (Japan Research Reactor No.1) in August 1957. Air absorbed doses from β and γ radiation, α and β radioactivity in air and the radioactivities in environmental samples were the monitoring items. For the monitoring of β and γ radiation and α and β radioactivity in air, monitoring station and the centralized automatic environmental radiation monitoring system applying a computer were established as a new challenging monitoring system for nuclear facility, which was the first one not only in Japan but also in the would in 1960 and since then the system has been renewed two times (in 1973 and 1988) by introducing the latest technology in the fields of radiation detection and computer control at each stage. Present system renewed in 1988 was designed to prevent the interruption of monitoring due to computer troubles, communication troubles and power failures especially an instant voltage drop arisen from thunder by reflecting the experiences through the operation and maintenance of the former system. Dual telemeters whose power is constantly supplied via batteries (capable of 10 min monitoring after power failure) are equipped in the monitoring center to cope with telemeter troubles, which has operated successfully without any suspension being attributable to the power failures and telemeter troubles

Life Support Systems: Environmental Monitoring

Data.gov (United States)

National Aeronautics and Space Administration — The Advanced Exploration Systems (AES) Life Support Systems project Environmental Monitoring (EM) systems task objectives are to develop and demonstrate onboard...

Acoustic emission leak monitoring system LMS-96

International Nuclear Information System (INIS)

Liska, J.; Cvrcek, M.; Mueller, L.

1997-01-01

On-line acoustic emission leak monitoring under industrial conditions of nuclear power plants is a problem with specific features setting specific demands on the leak monitoring system. The paper briefly reviews those problems (attenuation pattern of a real structure, acoustic background, alarm system, etc.) and the solution of some of them is discussed. Information is presented on the Acoustic Emission Leak Monitoring System LMS-96 by SKODA NUCLEAR MACHINERY and the system's function is briefly described. (author)

Design, Manufacturing and Experimental Validation of Optical Fiber Sensors Based Devices for Structural Health Monitoring

Directory of Open Access Journals (Sweden)

Angela CORICCIATI

2016-06-01

Full Text Available The use of optical fiber sensors is a promising and rising technique used for Structural Health Monitoring (SHM, because permit to monitor continuously the strain and the temperature of the structure where they are applied. In the present paper three different types of smart devices, that are composite materials with an optical fiber sensor embedded inside them during the manufacturing process, are described: Smart Patch, Smart Rebar and Smart Textile, which are respectively a plate for local exterior intervention, a rod for shear and flexural interior reinforcement and a textile for an external whole application. In addition to the monitoring aim, the possible additional function of these devices could be the reinforcement of the structures where they are applied. In the present work, after technology manufacturing description, the experimental laboratory characterization of each device is discussed. At last, smart devices application on medium scale masonry walls and their validation by mechanical tests is described.

Portable water quality monitoring system

Science.gov (United States)

Nizar, N. B.; Ong, N. R.; Aziz, M. H. A.; Alcain, J. B.; Haimi, W. M. W. N.; Sauli, Z.

2017-09-01

Portable water quality monitoring system was a developed system that tested varied samples of water by using different sensors and provided the specific readings to the user via short message service (SMS) based on the conditions of the water itself. In this water quality monitoring system, the processing part was based on a microcontroller instead of Lead and Copper Rule (LCR) machines to receive the results. By using four main sensors, this system obtained the readings based on the detection of the sensors, respectively. Therefore, users can receive the readings through SMS because there was a connection between Arduino Uno and GSM Module. This system was designed to be portable so that it would be convenient for users to carry it anywhere and everywhere they wanted to since the processor used is smaller in size compared to the LCR machines. It was also developed to ease the user to monitor and control the water quality. However, the ranges of the sensors' detection still a limitation in this study.

Real-time performance monitoring and management system

Science.gov (United States)

Budhraja, Vikram S [Los Angeles, CA; Dyer, James D [La Mirada, CA; Martinez Morales, Carlos A [Upland, CA

2007-06-19

A real-time performance monitoring system for monitoring an electric power grid. The electric power grid has a plurality of grid portions, each grid portion corresponding to one of a plurality of control areas. The real-time performance monitoring system includes a monitor computer for monitoring at least one of reliability metrics, generation metrics, transmission metrics, suppliers metrics, grid infrastructure security metrics, and markets metrics for the electric power grid. The data for metrics being monitored by the monitor computer are stored in a data base, and a visualization of the metrics is displayed on at least one display computer having a monitor. The at least one display computer in one said control area enables an operator to monitor the grid portion corresponding to a different said control area.

Uranium concentration monitor manual: 2300 system

International Nuclear Information System (INIS)

Russo, P.A.; Sprinkle, J.K. Jr.; Stephens, M.M.

1985-04-01

This manual describes the design, operation, and procedures for measurement control for the automated uranium concentration monitor on the 2300 solvent extraction system at the Oak Ridge Y-12 Plant. The nonintrusive monitor provides a near-real time readout of uranium concentration at two locations simultaneously in the solvent extraction system for process monitoring and control. Detectors installed at the top of the extraction column and at the bottom of the backwash column acquire spectra of gamma rays from the solvent extraction solutions in the columns. Pulse-height analysis of these spectra gives the concentration of uranium in the organic product of the extraction column and in the aqueous product of the solvent extraction system. The visual readouts of concentrations for process monitoring are updated every 2 min for both detection systems. Simultaneously, the concentration results are shipped to a remote computer that has been installed by Y-12 to demonstrate automatic control of the solvent extraction system based on input of near-real time process operation information. 8 refs., 13 figs., 4 tabs

Standard-D hydrogen monitoring system, system design description

International Nuclear Information System (INIS)

Schneider, T.C.

1996-01-01

During most of the year, it is assumed that the vapor space in the 177 radioactive waste tanks on the Hanford Project site contain a uniform mixture of gases. Several of these waste tanks (currently twenty-five, 6 Double Shell Tanks and 19 Single Shell Tanks) were identified as having the potential for the buildup of gasses to a flammable level. An active ventilation system in the Double Shell Tanks and a passive ventilation system in the Single Shell Tanks provides a method of expelling gasses from the tanks. A gas release from a tank causes a temporary rise in the tank pressure, and a potential for increased concentration of hydrogen gas in the vapor space. The gas is released via the ventilation systems until a uniform gas mixture in the vapor space is once again achieved. The Standard Hydrogen Monitoring System (SHMS) is designed to monitor and quantify the percent hydrogen concentration during these potential gas releases. This document describes the design of the Standard-D Hydrogen Monitoring System, (SHMS-D) and its components as it differs from the original SHMS

Radiation monitoring system based on EPICS

International Nuclear Information System (INIS)

Wang Weizhen; Li Jianmin; Wang Xiaobing; Hua Zhengdong; Xu Xunjiang

2008-01-01

Shanghai Synchrotron Radiation Facility (SSRF for short) is a third-generation light source building in China, including a 150 MeV injector, 3.5 GeV booster, 3.5 GeV storage ring and an amount of beam line stations. During operation, a mass of Synchrotron Radiation will be produced by electrons in the booster and the storage ring. Bremsstrahlung and neutrons will also be produced as a result of the interaction between the electrons, especially the beam loss, and the wall of the vacuum beam pipe. SSRF Radiation Monitoring System is established for monitoring the radiation dosage of working area and environment while SSRF operating. The system consists of detectors, intelligent data-collecting modules, monitoring computer, and managing computer. The software system is developed based on EPICS (Experimental Physics and Industrial Control System), implementing the collecting and monitoring the data output from intelligent modules, analyzing the data, and so on. (authors)

FFTF fission gas monitor computer system

International Nuclear Information System (INIS)

Hubbard, J.A.

1987-01-01

The Fast Flux Test Facility (FFTF) is a liquid-metal-cooled test reactor located on the Hanford site. A dual computer system has been developed to monitor the reactor cover gas to detect and characterize any fuel or test pin fission gas releases. The system acquires gamma spectra data, identifies isotopes, calculates specific isotope and overall cover gas activity, presents control room alarms and displays, and records and prints data and analysis reports. The fission gas monitor system makes extensive use of commercially available hardware and software, providing a reliable and easily maintained system. The design provides extensive automation of previous manual operations, reducing the need for operator training and minimizing the potential for operator error. The dual nature of the system allows one monitor to be taken out of service for periodic tests or maintenance without interrupting the overall system functions. A built-in calibrated gamma source can be controlled by the computer, allowing the system to provide rapid system self tests and operational performance reports

Moisture monitoring and control system engineering study

International Nuclear Information System (INIS)

Carpenter, K.E.; Fadeff, J.G.

1995-01-01

During the past 50 years, a wide variety of chemical compounds have been placed in the 149 single-shell tanks (SSTS) on the Hanford Site. A concern relating to chemical stability, chemical control, and safe storage of the waste is the potential for propagating reactions as a result of ferrocyanide-oxidizer and organic-oxidizer concentrations in the SSTS. Propagating reactions in fuel-nitrate mixtures are precluded if the amounts of fuel and moisture present in the waste are within specified limits. Because most credible ignition sources occur near the waste surface, the main emphasis of this study is toward monitoring and controlling moisture in the top 14 cm (5.5 in.) of waste. The purpose of this engineering study is to recommend a moisture monitoring and control system for use in SSTs containing sludge and saltcake. This study includes recommendations for: (1) monitoring and controlling moisture in SSTs; (2) the fundamental design criteria for a moisture monitoring and control system; and (3) criteria for the deployment of a moisture monitoring and control system in hanford Site SSTs. To support system recommendations, technical bases for selecting and using a moisture monitoring and control system are presented. Key functional requirements and a conceptual design are included to enhance system development and establish design criteria

The SSRL injector beam position monitoring systems

International Nuclear Information System (INIS)

Lavender, W.; Baird, S.; Brennan, S.; Borland, M.; Hettel, R.; Nuhn, H.D.; Ortiz, R.; Safranek, J.; Sebek, J.; Wermelskirchen, C.; Yang, J.

1991-01-01

The beam position monitoring system of the SSRL injector forms a vital component of its operation. Several different types of instrumentation are used to measure the position or intensity of the electron beam in the injector. These include current toroids, fluorescent screens, Faraday cups, the 'Q' meter, a synchrotron light monitor, and electron beam position monitors. This paper focuses on the use of the electron beam position monitors to measure electron trajectories in the injector transport lines and the booster ring. The design of the beam position monitors is described in another paper to be presented at this conference. There are three different beam position monitor systems in the injector. One system consists of a set of five BPMs located on the injection transport line from the linac to the booster (known as the LTB line). There is a second system of six BPMs located on the ejection transport line (known as the BTS line). Finally, there is an array of 40 BPMs installed on the main booster ring itself. This article describes the software and processing electronics of the systems used to measure electron beam trajectories for the new SSRL injector for SPEAR

Ulysses spacecraft control and monitoring system

Science.gov (United States)

Hamer, P. A.; Snowden, P. J.

1991-01-01

The baseline Ulysses spacecraft control and monitoring system (SCMS) concepts and the converted SCMS, residing on a DEC/VAX 8350 hardware, are considered. The main functions of the system include monitoring and displaying spacecraft telemetry, preparing spacecraft commands, producing hard copies of experimental data, and archiving spacecraft telemetry. The SCMS system comprises over 20 subsystems ranging from low-level utility routines to the major monitoring and control software. These in total consist of approximately 55,000 lines of FORTRAN source code and 100 VMS command files. The SCMS major software facilities are described, including database files, telemetry processing, telecommanding, archiving of data, and display of telemetry.

Big data-enabled multiscale serviceability analysis for aging bridges☆

Directory of Open Access Journals (Sweden)

Yu Liang

2016-08-01

Full Text Available This work is dedicated to constructing a multi-scale structural health monitoring system to monitor and evaluate the serviceability of bridges based on the Hadoop Ecosystem (MS-SHM-Hadoop. By taking the advantages of the fault-tolerant distributed file system called the Hadoop Distributed File System (HDFS and high-performance parallel data processing engine called MapReduce programming paradigm, MS-SHM-Hadoop features include high scalability and robustness in data ingestion, fusion, processing, retrieval, and analytics. MS-SHM-Hadoop is a multi-scale reliability analysis framework, which ranges from nationwide bridge-surveys, global structural integrity analysis, and structural component reliability analysis. This Nationwide bridge survey uses deep-learning techniques to evaluate the bridge serviceability according to real-time sensory data or archived bridge-related data such as traffic status, weather conditions and bridge structural configuration. The global structural integrity analysis of a targeted bridge is made by processing and analyzing the measured vibration signals incurred by external loads such as wind and traffic flow. Component-wise reliability analysis is also enabled by the deep learning technique, where the input data is derived from the measured structural load effects, hyper-spectral images, and moisture measurement of the structural components. As one of its major contributions, this work employs a Bayesian network to formulate the integral serviceability of a bridge according to its components serviceability and inter-component correlations. Here the inter-component correlations are jointly specified using a statistics-oriented machine learning method (e.g., association rule learning or structural mechanics modeling and simulation.

National Satellite Forest Monitoring systems for REDD+

Science.gov (United States)

Jonckheere, I. G.

2012-12-01

Reducing Emissions from Deforestation and Forest Degradation (REDD) is an effort to create a financial value for the carbon stored in forests, offering incentives for developing countries to reduce emissions from forested lands and invest in low-carbon paths to sustainable development. "REDD+" goes beyond deforestation and forest degradation, and includes the role of conservation, sustainable management of forests and enhancement of forest carbon stocks. In the framework of getting countries ready for REDD+, the UN-REDD Programme assists developing countries to prepare and implement national REDD+ strategies. For the monitoring, reporting and verification, FAO supports the countries to develop national satellite forest monitoring systems that allow for credible measurement, reporting and verification (MRV) of REDD+ activities. These are among the most critical elements for the successful implementation of any REDD+ mechanism. The UN-REDD Programme through a joint effort of FAO and Brazil's National Space Agency, INPE, is supporting countries to develop cost- effective, robust and compatible national monitoring and MRV systems, providing tools, methodologies, training and knowledge sharing that help countries to strengthen their technical and institutional capacity for effective MRV systems. To develop strong nationally-owned forest monitoring systems, technical and institutional capacity building is key. The UN-REDD Programme, through FAO, has taken on intensive training together with INPE, and has provided technical help and assistance for in-country training and implementation for national satellite forest monitoring. The goal of the support to UN-REDD pilot countries in this capacity building effort is the training of technical forest people and IT persons from interested REDD+ countries, and to set- up the national satellite forest monitoring systems. The Brazilian forest monitoring system, TerraAmazon, which is used as a basis for this initiative, allows

Automated Vehicle Monitoring System

OpenAIRE

Wibowo, Agustinus Deddy Arief; Heriansyah, Rudi

2014-01-01

An automated vehicle monitoring system is proposed in this paper. The surveillance system is based on image processing techniques such as background subtraction, colour balancing, chain code based shape detection, and blob. The proposed system will detect any human's head as appeared at the side mirrors. The detected head will be tracked and recorded for further action.

Impact Localization Method for Composite Plate Based on Low Sampling Rate Embedded Fiber Bragg Grating Sensors

Directory of Open Access Journals (Sweden)

Zhuo Pang

2017-01-01

Full Text Available Fiber Bragg Grating (FBG sensors have been increasingly used in the field of Structural Health Monitoring (SHM in recent years. In this paper, we proposed an impact localization algorithm based on the Empirical Mode Decomposition (EMD and Particle Swarm Optimization-Support Vector Machine (PSO-SVM to achieve better localization accuracy for the FBG-embedded plate. In our method, EMD is used to extract the features of FBG signals, and PSO-SVM is then applied to automatically train a classification model for the impact localization. Meanwhile, an impact monitoring system for the FBG-embedded composites has been established to actually validate our algorithm. Moreover, the relationship between the localization accuracy and the distance from impact to the nearest sensor has also been studied. Results suggest that the localization accuracy keeps increasing and is satisfactory, ranging from 93.89% to 97.14%, on our experimental conditions with the decrease of the distance. This article reports an effective and easy-implementing method for FBG signal processing on SHM systems of the composites.

Current status of technology development on remote monitoring system

International Nuclear Information System (INIS)

Yoon, Wan Ki; Lee, Y. K.; Lee, Y. D.; Na, W. W.

1997-03-01

IAEA is planning to perform the remote monitoring system in nuclear facility in order to reinforce the economical and efficient inspection. National lab. in U.S. is developing the corresponding core technology and field trial will be done to test the remote monitoring system by considering the case that it replace the current safeguards system. U.S. setup the International Remote Monitoring Project to develop the technology. IAEA makes up remote monitoring team and setup the detail facility to apply remote monitoring system. Therefore, early participation in remote monitoring technology development will make contribution in international remote monitoring system and increase the transparency and confidence in domestic nuclear activities. (author). 12 refs., 20 figs

Passive and Active Sensing Technologies for Structural Health Monitoring

Science.gov (United States)

Do, Richard

A combination of passive and active sensing technologies is proposed as a structural health monitoring solution for several applications. Passive sensing is differentiated from active sensing in that with the former, no energy is intentionally imparted into the structure under test; sensors are deployed in a pure detection mode for collecting data mined for structural health monitoring purposes. In this thesis, passive sensing using embedded fiber Bragg grating optical strain gages was used to detect varying degrees of impact damage using two different classes of features drawn from traditional spectral analysis and auto-regressive time series modeling. The two feature classes were compared in detail through receiver operating curve performance analysis. The passive detection problem was then augmented with an active sensing system using ultrasonic guided waves (UGWs). This thesis considered two main challenges associated with UGW SHM including in-situ wave propagation property determination and thermal corruption of data. Regarding determination of wave propagation properties, of which dispersion characteristics are the most important, a new dispersion curve extraction method called sparse wavenumber analysis (SWA) was experimentally validated. Also, because UGWs are extremely sensitive to ambient temperature changes on the structure, it significantly affects the wave propagation properties by causing large errors in the residual error in the processing of the UGWs from an array. This thesis presented a novel method that compensates for uniform temperature change by considering the magnitude and phase of the signal separately and applying a scalable transformation.

Shared performance monitor in a multiprocessor system

Science.gov (United States)

Chiu, George; Gara, Alan G.; Salapura, Valentina

2012-07-24

A performance monitoring unit (PMU) and method for monitoring performance of events occurring in a multiprocessor system. The multiprocessor system comprises a plurality of processor devices units, each processor device for generating signals representing occurrences of events in the processor device, and, a single shared counter resource for performance monitoring. The performance monitor unit is shared by all processor cores in the multiprocessor system. The PMU comprises: a plurality of performance counters each for counting signals representing occurrences of events from one or more the plurality of processor units in the multiprocessor system; and, a plurality of input devices for receiving the event signals from one or more processor devices of the plurality of processor units, the plurality of input devices programmable to select event signals for receipt by one or more of the plurality of performance counters for counting, wherein the PMU is shared between multiple processing units, or within a group of processors in the multiprocessing system. The PMU is further programmed to monitor event signals issued from non-processor devices.

An automated neutron monitor maintenance system

International Nuclear Information System (INIS)

Moore, F.S.; Griffin, J.C.; Odell, D.M.C.

1996-01-01

Neutron detectors are commonly used by the nuclear materials processing industry to monitor fissile materials in process vessels and tanks. The proper functioning of these neutron monitors must be periodically evaluated. We have developed and placed in routine use a PC-based multichannel analyzer (MCA) system for on-line BF3 and He-3 gas-filled detector function testing. The automated system: 1) acquires spectral data from the monitor system, 2) analyzes the spectrum to determine the detector's functionality, 3) makes suggestions for maintenance or repair, as required, and 4) saves the spectrum and results to disk for review. The operator interface has been designed to be user-friendly and to minimize the training requirements of the user. The system may also be easily customized for various applications

Integrated environmental monitoring and information system

International Nuclear Information System (INIS)

Klinda, J.; Lieskovska, Z.

1998-01-01

The concept of the environmental monitoring within the territory of the Slovak Republic and the concept of the integrated environmental information system of the Slovak Republic were accepted and confirmed by the Government Order No. 449/1992. The state monitoring system covering the whole territory of Slovakia is the most important and consists of 13 Partial Monitoring Systems (PMSs). List of PMSs is included. The listed PMSs are managed according to the concept of the Sectoral Information System (SIS) of the Ministry of the Environment of the Slovak Republic (MESR) which was established by the National Council Act No. 261/1995 Coll. on the SIS. The SIS consists of 18 subsystems which are listed. The overviews of budget of PMSs as well as of environmental publications and periodicals of the MESR are included

Remote Maintenance Monitoring System -

Data.gov (United States)

Department of Transportation — The Remote Maintenance and Monitoring System (RMMS) is a collection of subsystems that includes telecommunication components, hardware, and software, which serve to...

Structure health monitoring system using internet and database technologies

International Nuclear Information System (INIS)

Kwon, Il Bum; Kim, Chi Yeop; Choi, Man Yong; Lee, Seung Seok

2003-01-01

Structural health monitoring system should developed to be based on internet and database technology in order to manage efficiently large structures. This system is operated by internet connected with the side of structures. The monitoring system has some functions: self monitoring, self diagnosis, and self control etc. Self monitoring is the function of sensor fault detection. If some sensors are not normally worked, then this system can detect the fault sensors. Also Self diagnosis function repair the abnormal condition of sensors. And self control is the repair function of the monitoring system. Especially, the monitoring system can identify the replacement of sensors. For further study, the real application test will be performed to check some unconvince.

Structural health monitoring system using internet and database technologies

Energy Technology Data Exchange (ETDEWEB)

Kim, Chi Yeop; Choi, Man Yong; Kwon, Il Bum; Lee, Seung Seok [Nonstructive Measurment Lab., KRISS, Daejeon (Korea, Republic of)

2003-07-01

Structure health monitoring system should develope to be based on internet and database technology in order to manage efficiency large structures. This system is operated by internet connected with the side of structures. The monitoring system has some functions: self monitoring, self diagnosis, and self control etc. Self monitoring is the function of sensor fault detection. If some sensors are not normally worked, then this system can detect the fault sensors. Also Self diagnosis function repair the abnormal condition of sensors. And self control is the repair function of the monitoring system. Especially, the monitoring system can identify the replacement of sensors. For further study, the real application test will be performed to check some unconviniences.

Structure health monitoring system using internet and database technologies

Energy Technology Data Exchange (ETDEWEB)

Kwon, Il Bum; Kim, Chi Yeop; Choi, Man Yong; Lee, Seung Seok [Smart Measurment Group. Korea Resarch Institute of Standards and Science, Saejeon (Korea, Republic of)

2003-05-15

Structural health monitoring system should developed to be based on internet and database technology in order to manage efficiently large structures. This system is operated by internet connected with the side of structures. The monitoring system has some functions: self monitoring, self diagnosis, and self control etc. Self monitoring is the function of sensor fault detection. If some sensors are not normally worked, then this system can detect the fault sensors. Also Self diagnosis function repair the abnormal condition of sensors. And self control is the repair function of the monitoring system. Especially, the monitoring system can identify the replacement of sensors. For further study, the real application test will be performed to check some unconvince.

Structural health monitoring system using internet and database technologies

International Nuclear Information System (INIS)

Kim, Chi Yeop; Choi, Man Yong; Kwon, Il Bum; Lee, Seung Seok

2003-01-01

Structure health monitoring system should develope to be based on internet and database technology in order to manage efficiency large structures. This system is operated by internet connected with the side of structures. The monitoring system has some functions: self monitoring, self diagnosis, and self control etc. Self monitoring is the function of sensor fault detection. If some sensors are not normally worked, then this system can detect the fault sensors. Also Self diagnosis function repair the abnormal condition of sensors. And self control is the repair function of the monitoring system. Especially, the monitoring system can identify the replacement of sensors. For further study, the real application test will be performed to check some unconviniences.

Loose parts monitoring system

International Nuclear Information System (INIS)

Wakasa, Kohji; Nishida, Eiichi; Ishii, Kazuo; Yamanaka, Hiroto.

1987-01-01

In the loose parts monitoring system (LPMS), installed for integrity monitoring of the nuclear power plants; when there occur foreign metallic objects in the reactor primary system, including a steam generator and the piping, the sounds caused by them moving with the cooling water and thereby getting in contact with various structures are detected. Its purpose is, therefore, to detect any abnormality in the reactor plant system through such abnormal sounds due to loose or fallen supports etc., and so provide this information to the reactor operators. In principle, accelerometers are distributed in such as reactor vessel, steam generator, coolant pumps, etc., so that various sounds are collected and converted into electrical signals, followed by analysis of the data. Described are the LPMS configuration/functions, the course taken in LPMS development, future problems, etc. (Mori, K.)

OPTIMIZATION METHODS FOR HYDROECOLOGICAL MONITORING SYSTEMS

Directory of Open Access Journals (Sweden)