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  Subjects -> ENERGY (Total: 246 journals)
    - ENERGY (162 journals)
    - ENERGY: GENERAL (8 journals)
    - NUCLEAR ENERGY (21 journals)
    - PETROLEUM AND GAS (47 journals)
    - WIND ENERGY (8 journals)

ENERGY (162 journals)                  1 2 | Last

Advances in Building Energy Research     Hybrid Journal   (Followers: 11)
Advances in High Energy Physics     Open Access   (Followers: 12)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 14)
American Journal of Energy Research     Open Access   (Followers: 5)
Annals of Nuclear Energy     Hybrid Journal   (Followers: 7)
Annual Reports on NMR Spectroscopy     Full-text available via subscription   (Followers: 1)
Annual Review of Resource Economics     Full-text available via subscription   (Followers: 10)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Solar Energy     Hybrid Journal   (Followers: 10)
Archives of Thermodynamics     Open Access   (Followers: 4)
Atomic Energy     Hybrid Journal   (Followers: 5)
Atoms for Peace: an International Journal     Hybrid Journal   (Followers: 3)
Biofuels     Hybrid Journal   (Followers: 7)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 5)
Bulletin de droit nucleaire     Full-text available via subscription   (Followers: 1)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 12)
Canadian Water Resources Journal     Hybrid Journal   (Followers: 19)
Carbon Management     Hybrid Journal   (Followers: 5)
Catalysis for Sustainable Energy     Open Access   (Followers: 2)
Chain Reaction     Full-text available via subscription  
Clefs CEA     Full-text available via subscription   (Followers: 1)
Computational Water, Energy, and Environmental Engineering     Open Access   (Followers: 2)
Continental Journal of Renewable Energy     Open Access   (Followers: 9)
Current Sustainable/Renewable Energy Reports     Hybrid Journal   (Followers: 2)
Dams and Reservoirs     Hybrid Journal   (Followers: 2)
Development of Energy Science     Open Access   (Followers: 2)
Distributed Generation & Alternative Energy Journal     Hybrid Journal   (Followers: 1)
E3S Web of Conferences     Open Access  
Economics and Policy of Energy and the Environment     Full-text available via subscription   (Followers: 1)
Electrical and Power Engineering Frontier     Open Access   (Followers: 7)
Electronic Journal of Energy & Environment     Open Access   (Followers: 8)
Energy     Partially Free   (Followers: 21)
Energy & Fuels     Full-text available via subscription   (Followers: 22)
Energy and Buildings     Hybrid Journal   (Followers: 6)
Energy and Environment Research     Open Access   (Followers: 8)
Energy and Power Engineering     Open Access   (Followers: 7)
Energy Conversion and Management     Hybrid Journal   (Followers: 6)
Energy Efficiency     Hybrid Journal   (Followers: 10)
Energy Policy     Partially Free   (Followers: 37)
Energy Prices and Taxes     Full-text available via subscription   (Followers: 4)
Energy Procedia     Open Access   (Followers: 2)
Energy Science & Engineering     Open Access   (Followers: 3)
Energy Science and Technology     Open Access   (Followers: 9)
Energy Strategy Reviews     Partially Free   (Followers: 4)
Energy Studies Review     Open Access   (Followers: 3)
Energy Systems     Hybrid Journal   (Followers: 8)
Energy Technology     Partially Free   (Followers: 2)
Energy, Sustainability and Society     Open Access   (Followers: 15)
Environmental Progress & Sustainable Energy     Hybrid Journal   (Followers: 3)
EPJ Photovoltaics     Open Access  
Frontiers in Energy     Hybrid Journal   (Followers: 2)
Frontiers in Energy Research     Open Access   (Followers: 1)
Fuel and Energy Abstracts     Full-text available via subscription   (Followers: 5)
Functional Materials Letters     Hybrid Journal   (Followers: 1)
Gcb Bioenergy     Hybrid Journal   (Followers: 2)
Geothermal Energy     Open Access   (Followers: 1)
GeoWorld     Full-text available via subscription   (Followers: 2)
Green     Full-text available via subscription   (Followers: 1)
IEA Electricity Information     Full-text available via subscription   (Followers: 5)
IEA Natural Gas Information     Full-text available via subscription   (Followers: 4)
IEEE Power and Energy     Full-text available via subscription   (Followers: 8)
IEEE Transactions on Energy Conversion     Hybrid Journal   (Followers: 6)
IEEE Transactions on Nuclear Science     Hybrid Journal   (Followers: 7)
IEEE Transactions on Power Systems     Hybrid Journal   (Followers: 9)
IET Power Electronics     Hybrid Journal   (Followers: 7)
IngenierĂ­a EnergĂ©tica     Open Access  
Innovations : Technology, Governance, Globalization     Hybrid Journal   (Followers: 6)
International Journal of Alternative Propulsion     Hybrid Journal   (Followers: 1)
International Journal of Ambient Energy     Hybrid Journal   (Followers: 2)
International Journal of Applied Power Engineering     Open Access   (Followers: 1)
International Journal of Clean Coal and Energy     Open Access   (Followers: 4)
International Journal of Critical Infrastructure Protection     Hybrid Journal   (Followers: 5)
International Journal of Electric and Hybrid Vehicles     Hybrid Journal   (Followers: 3)
International Journal of Emerging Electric Power Systems     Full-text available via subscription   (Followers: 4)
International Journal of Emerging Multidisciplinary Fluid Sciences     Full-text available via subscription  
International Journal of Energy and Environmental Engineering     Open Access   (Followers: 2)
International Journal of Energy and Power     Open Access   (Followers: 4)
International Journal of Energy Engineering     Open Access   (Followers: 11)
International Journal of Energy Research     Hybrid Journal   (Followers: 9)
International Journal of Energy Science     Open Access   (Followers: 1)
International Journal of Flow Control     Full-text available via subscription   (Followers: 2)
International Journal of Global Energy Issues     Hybrid Journal   (Followers: 7)
International Journal of Green Energy     Hybrid Journal   (Followers: 5)
International Journal of Hydrogen Energy     Partially Free   (Followers: 9)
International Journal of Marine Energy     Full-text available via subscription   (Followers: 1)
International Journal of Nuclear Desalination     Hybrid Journal   (Followers: 2)
International Journal of Nuclear Energy Science and Technology     Hybrid Journal   (Followers: 2)
International Journal of Nuclear Governance, Economy and Ecology     Hybrid Journal   (Followers: 2)
International Journal of Nuclear Hydrogen Production and Applications     Hybrid Journal   (Followers: 2)
International Journal of Nuclear Knowledge Management     Hybrid Journal   (Followers: 2)
International Journal of Power and Energy Conversion     Hybrid Journal   (Followers: 3)
International Journal of Regulation and Governance     Hybrid Journal   (Followers: 2)
International Journal of Sustainable Energy     Hybrid Journal   (Followers: 9)
International Journal of Sustainable Energy Planning and Management     Open Access  
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Thermodynamics     Open Access   (Followers: 1)
ISRN Power Engineering     Open Access   (Followers: 1)
ISRN Renewable Energy     Open Access  
Journal of Alternate Energy Sources & Technologies     Full-text available via subscription   (Followers: 1)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 3)

        1 2 | Last

Journal Cover Structural Control and Health Monitoring
   [6 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1545-2255 - ISSN (Online) 1545-2263
     Published by John Wiley and Sons Homepage  [1603 journals]   [SJR: 1.148]   [H-I: 21]
  • Probabilistic identification of simulated damage on the Dowling Hall
           footbridge through Bayesian finite element model updating
    • Authors: Iman Behmanesh; Babak Moaveni
      Pages: n/a - n/a
      Abstract: This paper presents a probabilistic damage identification study on a full‐scale structure, the Dowling Hall footbridge, through a Bayesian finite element (FE) model updating. The footbridge is located at Tufts University and is equipped with a continuous monitoring system that measures its ambient acceleration response. A set of data is recorded once every hour or when triggered by large vibrations. The modal parameters of the footbridge are extracted from each set of data and are used for FE model updating. In this study, effects of physical damage are simulated by loading a small segment of the footbridge deck with concrete blocks. The footbridge deck is divided into five segments in an FE model of the test structure, and the added mass on each segment is considered as an updating parameter. Overall, 72 sets of data are collected during the loading period, and different subsets of these data are used to find the location and extent of the damage (added mass). The adaptive Metropolis–Hastings algorithm with adaption on the proposal probability density function is successfully used to generate Markov Chains for sampling the posterior probability distributions of the five updating parameters. Effects of the number of data sets used in the identification process are investigated on the posterior probability distributions of the updating parameters. The probabilistic model updating framework accurately predicts the simulated damage and the level of confidence on the obtained results. The maximum a‐posteriori estimates of damage in the probabilistic approach are found to be in good agreement with their corresponding deterministic counterparts. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-08-05T04:08:24.941908-05:
      DOI: 10.1002/stc.1684
       
  • Multi‐sensing NDT for damage assessment of concrete masonry walls
    • Authors: Fuad Khan; Satish Rajaram, Prashanth A. Vanniamparambil, Mohammad Bolhassani, Ahmad Hamid, Antonios Kontsos, Ivan Bartoli
      Pages: n/a - n/a
      Abstract: This paper presents a hybrid non‐destructive testing (NDT) approach based on (non‐contact) infrared thermography (IRT), (passive) acoustic emission (AE), and (active) ultrasonic (UT) techniques for effective damage assessment of partially grouted concrete masonry walls (PGMW). This hybrid monitoring approach could be implemented for the health monitoring of concrete masonry structures. The implementation of this system assists the cross validation of in‐situ recorded information for structural damage assessment. NDT was performed on PGMW subjected to cyclic horizontal loading. The obtained IRT, AE, and UT results successfully monitored the progressive damage process throughout the loading history. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-07-28T23:26:04.332182-05:
      DOI: 10.1002/stc.1680
       
  • Compressive sensing‐based lost data recovery of fast‐moving
           wireless sensing for structural health monitoring
    • Authors: Yuequan Bao; Yan Yu, Hui Li, Xingquan Mao, Wenfeng Jiao, Zilong Zou, Jinping Ou
      Pages: n/a - n/a
      Abstract: Wireless sensor technology‐based structural health monitoring (SHM) has been widely investigated recently. This paper proposes a fast‐moving wireless sensing technique for the SHM of bridges along a highway or in a city in which the wireless sensor nodes are installed on the bridges to automatically acquire data, and a fast‐moving vehicle with an onboard wireless base station periodically collects the data without interrupting traffic. For the fast‐moving wireless sensing technique, the reliable wireless data transmission between the sensor nodes and the fast‐moving base station is one of the key issues. In fast‐moving states, the data packet loss rates during wireless data transmission between the moving base station and the sensor nodes will increase remarkably. In this paper, the data packets loss in the fast‐moving states is first investigated through a series of experiments. To solve the data packets loss problem, the compressive sensing (CS)‐based lost data recovery approach is proposed. A field test on a cable‐stayed bridge is performed to further illustrate the data packet loss in the fast‐moving wireless sensing technique and the ability of the CS‐based approach for lost data recovery. The experimental and field test results indicate that the Doppler effect is the main reason causing data packet loss for the fast‐moving wireless sensing technique, and the feasibility and efficiency of the CS‐based lost data recovery approach are validated Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-07-28T23:24:48.913065-05:
      DOI: 10.1002/stc.1681
       
  • Partially bonded fiber‐reinforced elastomeric isolators
           (PB‐FREIs)
    • Authors: Niel C. Van Engelen; Peyman M. Osgooei, Michael J. Tait, Dimitrios Konstantinidis
      Pages: n/a - n/a
      Abstract: Although stable unbonded fiber‐reinforced elastomeric isolators (SU‐FREIs) have desirable characteristics for seismic isolation, the unbonded application also introduces limitations in comparison with bonded elastomeric isolators. SU‐FREIs are not capable of resisting tensile forces, making SU‐FREIs unsuited for situations where overturning is of concern or where large vertical accelerations are anticipated. Furthermore, as SU‐FREIs rely on friction to transfer horizontal forces, the isolator could potentially slip under certain loading conditions, resulting in permanent displacements. This paper proposes that concerns over the transfer of tensile forces and potential slip can be addressed by partially bonding the SU‐FREI to the upper and lower supports. In this way, partially bonded FREIs (PB‐FREIs) not only retain the beneficial characteristics of an unbonded FREI but also inherit characteristics of a bonded isolator; notably tensile and horizontal forces can be transferred through the partial bond. Experimental results from isolators tested unbonded and partially bonded under vertical compression are used to evaluate a finite element model. The experimental data and finite element analysis demonstrate that portions of a FREI can be bonded without substantially altering the rollover characteristics of the isolator within the range of average vertical compressive and tensile stresses considered. Despite an unconventional deformed shape under tensile vertical stress, the horizontal force–displacement relationship exhibits negligible deviation from a conventional unbonded SU‐FREI under a compressive vertical stress. It is postulated that with further development, partially bonded FREIs can retain the beneficial characteristics of unbonded FREIs while addressing concerns over tensile forces and slip. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-07-28T23:12:01.695306-05:
      DOI: 10.1002/stc.1682
       
  • Assessing uncertainty in operational modal analysis incorporating multiple
           setups using a Bayesian approach
    • Authors: Feng‐Liang Zhang; Siu‐Kui Au, Heung‐Fai Lam
      Pages: n/a - n/a
      Abstract: A Bayesian statistical framework was previously developed for modal identification of well‐separated modes incorporating ambient vibration data, that is, operational modal analysis, from multiple setups. An efficient strategy was developed for evaluating the most probable value of the modal parameters using an iterative procedure. As a sequel to the development, this paper investigates the posterior uncertainty of the modal parameters in terms of their covariance matrix, which is mathematically equal to the inverse of the Hessian of the negative log‐likelihood function evaluated at the most probable value. Computational issues arising from the norm constraint of the global mode shape are addressed. Analytical expressions are derived for the Hessian so that it can be evaluated accurately and efficiently without resorting to finite difference. The proposed method is verified using synthetic and laboratory data. It is also applied to field test data, which reveals some challenges in operational modal analysis incorporating multiple setups. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-07-28T23:10:34.37728-05:0
      DOI: 10.1002/stc.1679
       
  • Damage localization based on symbolic time series analysis
    • Authors: Mehrisadat Makki Alamdari; Bijan Samali, Jianchun Li
      Pages: n/a - n/a
      Abstract: The objective of this paper is to localize damage in a single or multiple state at early stages of development on the basis of the principles of symbolic dynamics. Symbolic time series analysis (STSA) of noise‐contaminated responses is used for feature extraction to detect and localize a gradually evolving deterioration in the structure according to the changes in the statistical behaviour of symbol sequences. Basically, in STSA, statistical features of the symbol sequence can be used to describe the dynamic status of the system. Symbolic dynamics has some useful characteristics making it highly demanded for implementation in real‐time observation application such as SHM. First, it significantly reduces the dimension of information and provides information‐rich representation of the underlying data. Second, symbolic dynamics and the set of statistical measures built upon it represent a solid framework to address the main challenges of the analysis of nonstationary time data. Finally, STSA often allows capturing the main features of the underlying system whilst alleviating the effects of harmful noise. The method presented in this paper consists of four primary steps: (i) acquisition of the time series data; (ii) creating the symbol space to produce symbol sequences on the basis of the wavelet transformed version of time series data; (iii) developing the symbol probability vectors to achieve anomaly measures; and (iv) localizing damage on the basis of any sudden variation in anomaly measure of different locations. The method was applied on a flexural beam and a 2‐D planar truss bridge subjected to varying Gaussian excitation in presence of 2% white noise to examine the efficiency and limitations of the method. Simulation results under various damage conditions confirmed the efficiency of the proposed approach for localization of gradually evolving deterioration in the structure; however, for the future work, the method needs to be verified by experimental data. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-07-28T22:53:22.459024-05:
      DOI: 10.1002/stc.1683
       
  • Issue Information
    • Pages: i - ii
      Abstract: No abstract is available for this article.
      PubDate: 2014-07-21T04:04:05.408701-05:
      DOI: 10.1002/stc.1615
       
  • Innovative method of empirical mode decomposition as spatial tool for
           structural damage identification
    • Authors: D. Mallikarjuna Reddy; Praveen Krishna, Sathesa
      Pages: n/a - n/a
      Abstract: A new approach to sensitize detecting structural damage using empirical mode decomposition (EMD) of the spatial signals is proposed. The difference of undamaged and damaged spatial strain and strain energy data for the beam and bridge modes is processed through the EMD, which yields the respective IMF1, which shows that damage location can be identified distinctively for as low as 0.01% reduction in elemental stiffness of beam discretized with 30 elements. An analysis was also carried out for a two‐dimensional bridge model (I‐40). It can detect damage sensitivity up to 0.5% loss in stiffness of the bridge. EMD as a spatial analysis tool seems to be the most sensitive among all methods currently available. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-07-07T04:57:24.518876-05:
      DOI: 10.1002/stc.1676
       
  • Seismic evaluation and structural control of the historical Beylerbeyi
           Palace
    • Authors: Fuat Aras; Gulay Altay
      Pages: n/a - n/a
      Abstract: The Beylerbeyi Palace was built between 1861 and 1865 on the Asian shore of Istanbul, and it is within the cultural heritage treasury of the world. Recent earthquakes in the Mediterranean basin have highlighted the particular vulnerability of historic masonry buildings and the need of properly defining retrofitting measures. In this respect, structural behaviour and the earthquake performance of the palace have been investigated. It is seen that the inherent dynamic properties of the palace make it vulnerable to earthquake ground shaking. In order to reduce the affect of ground shaking, the use of base isolation system has been investigated. It is determined that base isolation can be used to reduce the earthquake effects on the palace and ensure the structural performance under maximum considered earthquake. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-06-27T02:20:38.559761-05:
      DOI: 10.1002/stc.1677
       
  • Experiments for seismic damage detection of a RC frame using ambient and
           forced vibration records
    • Authors: Jesús Valdés‐González; Jaime De‐la‐Colina, Carlos Alberto González‐Pérez
      Pages: n/a - n/a
      Abstract: This paper presents an experimental study conducted on a two‐story RC frame that was progressively damaged until it reached a significant structural damage. The RC frame was subjected to increasing dynamic load stages typical of growing‐intensity earthquake ground motions. The frame was excited with a testing pendulum, which is a device that excited the structure attached to the pendulum platform with a harmonic motion along one horizontal direction at selected frequencies. For each damage level, ambient and forced vibration tests were performed, and dynamic properties of the frame were estimated. It was possible to characterize the damage level of the RC frame in terms of the simple statistical correlation between a pair of frequency response functions obtained for the initial damage condition and the subsequent stages. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-06-26T03:11:51.111251-05:
      DOI: 10.1002/stc.1678
       
  • Localization of acoustic emission sources in structural health monitoring
           of masonry bridge
    • Authors: Qinghua Han; Jie Xu, Alberto Carpinteri, Giuseppe Lacidogna
      Pages: n/a - n/a
      Abstract: The application of the acoustic emission (AE) technique to monitoring the crack characterization in masonry structures is investigated in this paper. An improved approach, modified from the classical crack source localization method, is proposed to provide more reliable crack locations in masonry structures. The introduced parameter, degree of inhomogeneity ξ in the modified method, can help to decrease the unavoidable propagation delay related to refraction due to the layers in masonry material. The modified method is successfully applied to the AE source detection during the pencil-lead break test and the central pier settlement test of a masonry model bridge to analyze the crack pattern. It is shown that the proposed method is a reliable tool for crack source location in masonry structures. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-06-13T00:27:47.547722-05:
      DOI: 10.1002/stc.1675
       
  • Optical fiber-based sensors with flexible encapsulation for pavement
           behavior monitoring
    • Authors: Wanqiu Liu; Huaping Wang, Zhi Zhou, Xiaoying Xing, Dandan Cao, Zhen Jiang
      Pages: n/a - n/a
      Abstract: Owing to the increasing needs for robust highway pavement structural monitoring tools with high accuracy and functionality, this paper introduces some results from the research on developing optical fiber-based pavement behavior monitoring sensors. A new flexible encapsulation technique for optical fiber sensing element has been proposed to help the sensor withstand the harsh working environment and guarantee measuring accuracy. Both fiber Bragg grating and Brillouin optical time domain analysis/reflectometry-based sensors have been produced in a lab with the proposed encapsulation for high accuracy and distributed measurement, respectively. The precision of the fiber Bragg grating-based sensor has been specially calibrated in a lab. Lab and field tests have been carried out to study the effectiveness of the proposed sensors. It has been found that the proposed sensors have high survival rate (>75%) and are efficient for pavement structural behavior monitoring and damage detection. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-06-05T00:27:57.9533-05:00
      DOI: 10.1002/stc.1674
       
  • Inference of bond slip in prestressed tendons in concrete bridge girders
    • Authors: Siu Chun M. Ho; Liang Ren, Emad Labib, Aadit Kapadia, Yi-Lung Mo, Hongnan Li, Gangbing Song
      Pages: n/a - n/a
      Abstract: Prestressed concrete (PC) bridge girders have extra flexural strength due to embedded prestressing tendons. The level of strength depends on the integrity of the concrete-tendon bond in pretensioned PC structures, and this bond can be degraded in the presence of an adequately large mechanical force or over time because of accumulated damage. Bond degradation is characterized by the bond slip of the tendon from the host concrete, and in regards to PC structures, bond slip has only been measured from a global perspective. In this paper, a novel method was developed to measure for the first time the local strain of a prestressing tendon during bond slip. Fiber Bragg grating-based strain sensors were installed directly onto prestressing tendons within a PC girder to provide a local perspective of bond slip as the girder was loaded to failure. Measurement of the local strains in selected tendons, from the beginning of bond slip to the complete loss of the concrete-tendon bond, and the failure of the girder was enabled by the method. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-06-02T20:07:43.265258-05:
      DOI: 10.1002/stc.1669
       
  • Nonlinear data-driven computational models for response prediction and
           change detection
    • Authors: Armen Derkevorkian; Miguel Hernandez-Garcia, Hae-Bum Yun, Sami F. Masri, Peizhen Li
      Pages: n/a - n/a
      Abstract: Data are used from three relatively large-scale experimental soil-foundation-superstructure interaction (SFSI) systems to develop reduced-order computational models for response prediction and change-detection relevant to structural health monitoring and computational mechanics. The three systems under consideration consist of identical superstructures with: (i) fixed base; (ii) box foundation; and (iii) pile foundation. The three SFSI systems were developed and experimentally tested at Tongji University. In the first part of the study, a computational time-marching prediction framework is proposed by incorporating trained neural network(s) within an ordinary differential equation solver and dynamically predicting the response (i.e., displacement and velocity) of the SFSI systems to various earthquake excitations. Two approaches are investigated: global approach and subsystem approach. Both approaches are tested and validated with linear and nonlinear systems, and their respective pros and cons are discussed. In the second part of the study, the trained neural networks from the global approach are further used for change-detection in the SFSI systems. The detected changes in the systems are then quantified through a measure of a normalized error index. Challenges related to the physical interpretation of the quantified changes in the SFSI systems are addressed and discussed. It is shown that the general procedures adopted in this paper provide a robust nonlinear model that is reliable for computational studies, as well as furnishing a robust tool for detecting and quantifying inherent change in the system. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-05-30T01:55:40.559884-05:
      DOI: 10.1002/stc.1673
       
  • System identification of a historic swing truss bridge using a wireless
           sensor network employing orientation correction
    • Authors: Soojin Cho; Ryan K. Giles, Billie F. Spencer
      Pages: n/a - n/a
      Abstract: System identification was performed on the swing span of a steel truss bridge dating from 1896 using acceleration data collected from a wireless sensor network (WSN). The swing span can rotate 360° to allow river traffic to pass through the locks located under the bridge. The WSN installed on the swing span consists of 23 nodes that measure synchronized tri-axial acceleration. Five days of measured data were segmented according to three functional positions of the span (locked facing downstream, locked facing upstream, swung for river traffic) and load conditions. Subsequently, the modal parameters corresponding to the bridge's three functional positions were obtained using frequency domain decomposition method. The initial system identification of the bridge resulted in significant anomalies, in comparison with the finite element (FE) model. To improve the accuracy of the overall identification results, the sensor orientation correction technique is proposed for the measured data from the WSN. The improvement has been verified by comparing the orientation-corrected mode shapes with non-corrected mode shapes and FE mode shapes using the modal assurance criterion values. Analysis of the modal parameters inferred that the boundary conditions for the bridge positions are different because of the interaction of the locking mechanism with the abutments in those positions. The proposed approach for system identification, including sensor orientation correction, is to be used as part of the comprehensive structural heath monitoring strategy for this historic structure. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-05-30T01:11:21.812753-05:
      DOI: 10.1002/stc.1672
       
  • Performance of fiber-reinforced elastomeric base isolators under cyclic
           excitation
    • Authors: Animesh Das; Anjan Dutta, Sajal K. Deb
      Pages: n/a - n/a
      Abstract: This paper presents three-dimensional finite element models for the analysis of square fiber-reinforced elastomeric isolators (FREI) subjected to cyclic horizontal displacement and constant vertical load. Direction of applied displacement has been varied to evaluate their influence on the isolator performance. Both bonded and un-bonded boundary conditions at the top and bottom contact surfaces of isolator have been simulated in the analysis. It is observed that the un-bonded FREI are more effective in seismic isolation as compared with bonded FREI, and stresses developed under lateral displacement are also significantly lower in un-bonded FREI. Experimental validation has been carried out for un-bonded isolators and very good agreement is observed in terms of mechanical properties and deformed configuration. In the absence of any close form solution of un-bonded FREI due to its complex deformation pattern, finite element solution is observed to be sufficiently accurate for arriving at the design parameters of an isolator. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-05-21T01:15:11.81426-05:0
      DOI: 10.1002/stc.1668
       
  • Optimal design of distributed tuned mass dampers for passive vibration
           control of structures
    • Authors: F. Yang; R. Sedaghati, E. Esmailzadeh
      Pages: n/a - n/a
      Abstract: The distributed tuned mass damper (DTMD) system consists of multiple tuned mass dampers, which are designed to suppress the undesirable structural vibration over a bandwidth centered at a particular tuned frequency. In this study, an innovative practical approach to optimally design the DTMD system has been proposed. Comparisons were made between the optimal DTMD system, obtained based on the proposed design approach, and those using the conventional design approach. The superior performance and robustness of the optimally designed DTMD system based on the proposed approach compared with that based on the conventional approach have been demonstrated through illustrative examples. It has been shown that the proposed design approach provide a simple, clear, and straightforward way to effectively attain the optimum parameters of the DTMD system. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-05-21T01:12:10.595634-05:
      DOI: 10.1002/stc.1670
       
  • Amplitude and frequency independent cable damping of Sutong Bridge and
           Russky Bridge by magnetorheological dampers
    • Authors: Felix Weber; Hans Distl
      Pages: n/a - n/a
      Abstract: Two control approaches for magnetorheological (MR) dampers on cables based on collocated control without state estimation are formulated, which generate amplitude and frequency independent cable damping: cycle energy control and controlled viscous damping (CVD). The force tracking is solved by the inverted Bingham model whose parameters are fitted as function of current and frequency. Cycle energy control and CVD are experimentally validated by hybrid simulations and free decay tests on stay cables of the Sutong Bridge, China, and the Eiland Bridge, the Netherlands. The implementation of CVD on the Russky Bridge, Russia, includes two novelties: the force tracking also takes the actual MR damper temperature into account to ensure precise force tracking for MR damper temperatures −40 to +60 °C and the decentralised real-time control units with pulse width current modulation are installed next to each MR damper to avoid long direct current (DC) power lines with associated losses and thereby minimise power consumption. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-05-21T00:42:33.391893-05:
      DOI: 10.1002/stc.1671
       
  • Fuzzy logic control of a stiffness-adaptable seismic isolation system
    • Authors: Tzu-Kang Lin; Lyan-Ywan Lu, Hsun Chang
      Pages: n/a - n/a
      Abstract: Traditional passive isolation systems have been shown to provide satisfactory seismic mitigation performance under typical far-field earthquake conditions. However, because of the untunable designated isolation period, the performance of these systems is still strongly affected by the low-frequency resonance phenomenon observed during near-fault earthquakes, which are usually dominated by a long-duration impulse. The use of semi-active isolation systems with variable stiffness, which are usually equipped with a customized control algorithm to determine the isolation stiffness or period in real time, could be a promising solution to overcome this problem. To realize this technology, this study develops a smart isolation system that combines the leverage-type stiffness-controllable isolation system (LSCIS) with a simple fuzzy logic control (FLC). Because the proposed FLC merely requires feedback from the velocity and displacement responses of the isolation base, it is quite easily implemented. Theoretical analysis shows that the extreme displacement of the isolation level caused by near-fault seismic waves can be mitigated by the proposed system with tolerable acceleration response variations compared with that of the traditional passive isolation system. The movement of the pivot point of the LSCIS can also be adjusted to address the inherent hardware constraint that limits its practical application. Experimental verification conducted on a shake table further demonstrates the feasibility of integrating the LSCIS system with FLC after proper consideration of the friction effect generated by the leverage mechanism and the inevitable time delay effect. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-05-15T02:48:38.057729-05:
      DOI: 10.1002/stc.1667
       
  • Passive control of floating offshore wind turbine nacelle and spar
           vibrations by multiple tuned mass dampers
    • Authors: Van-Nguyen Dinh; Biswajit Basu
      Pages: n/a - n/a
      Abstract: This paper investigates the use of single and multiple tuned mass dampers (TMDs) for passive control of edgewise vibrations of nacelle/tower and spar of spar-type floating wind turbines (S-FOWTs). Uncontrolled and controlled mathematical models of the S-FOWT are developed by using Euler-Lagrangian energy formulations. In these models, the aerodynamic properties of the blade, variable mass and stiffness, gravity, the interactions among the blades, nacelle, spar and mooring system, the hydrodynamic effects, the restoring moment, and the buoyancy force are considered. The vibrations of the blades, nacelle, tower, and spar are coupled in all degrees of freedom and in all inertial, dissipative, and elastic components. In the controlled model, several set of horizontal TMDs are placed in the spar at various depths and the coupling of these TMDs with the nacelle and spar motions is considered. The control effectiveness is evaluated by the reduction of the root-mean-square and maximum response. The control feasibility is examined by using the spar sinking and the TMD maximum strokes. The investigations using nonlinear time–domain simulation show that a single TMD can reduce up to 40% of the nacelle sway displacement and the spar roll, and that the reduction observed with multiple TMDs is 50%. The influence of the spar TMD is more significant than that of the nacelle TMD. The spar TMDs are less effective when their positions are lower. In all the cases studied, good heave performance of the S-FOWT is maintained. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-05-15T01:55:11.246845-05:
      DOI: 10.1002/stc.1666
       
  • Retest of Neoprene seismic isolation bearings after 30 years
    • Authors: Niel C. Van Engelen; James M. Kelly
      Pages: n/a - n/a
      Abstract: This paper describes the retest of a set of Neoprene (Polychloroprene) steel reinforced elastomeric isolator bearings that were originally tested as part of an experimental program in 1981. The original bearings were tested on a shake table as a demonstration of the feasibility of base isolation for the seismic protection of buildings. Two types of bearings were provided, and not all were used. The unused bearings were stored unloaded at room temperature for over 30 years. Although there has been a very substantial improvement in the number and quality of the instrumentation available to the test program over the span of 30 years, it is possible to compare the results of relatively similar shake table tests on the bearings. The shake table tests are used to assess the changes in the horizontal stiffness and damping values for the bearings over this period. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-05-08T01:30:31.988429-05:
      DOI: 10.1002/stc.1665
       
  • Local positioning systems versus structural monitoring: a review
    • Authors: Lijun Wu; Fabio Casciati
      Pages: 1209 - 1221
      Abstract: Structural monitoring and structural health monitoring could take advantage from different devices to record the static or dynamic response of a structure. A positioning system provides displacement information on the location of moving objects, which is assumed to be the basic support to calibrate any structural mechanics model. The global positioning system could provide satisfactory accuracy in absolute displacement measurements. But the requirements of an open area position for the antennas and a roofed room for its data storage and power supply limit its flexibility and its applications. Several efforts are done to extend its field of application. The alternative is local positioning system. Non‐contact sensors can be easily installed on existing infrastructure in different locations without changing their properties: several technological approaches have been exploited: laser‐based, radar‐based, vision‐based, etc. In this paper, a number of existing options, together with their performances, are reviewed. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-01-19T21:29:12.401715-05:
      DOI: 10.1002/stc.1643
       
  • Stochastic optimization of shape‐memory‐alloy rubber bearing
           (SMARB) for isolating buildings against random earthquake
    • Authors: Sourav Gur; Sudib K. Mishra, Subrata Chakraborty
      Pages: 1222 - 1239
      Abstract: Shape‐memory‐alloy (SMA) aided isolation bearing has been proposed recently in order to achieve improved performances in several aspects, comparing the traditional bearings for isolation. The behavior of such system has been experimentally demonstrated and numerically simulated under recorded seismic ground motions. The present work deals with the study of optimum performance of SMA‐based isolation system under random earthquake. The stochastic response evaluation of the isolated building is performed by nonlinear random vibration analysis via stochastic linearization of load‐deformation hysteresis of SMA. The behavior of the stochastic responses indicates the existence of optimal value of transformation strength of SMA to minimize the superstructure acceleration and thereby most efficient isolation. Thus, a stochastic structural optimization problem is taken up in order to obtain the optimal transformation strength. A closed form expression of such optimal parameters are also presented, which may be used for establishing an initial design. The viability of the optimization study is justified by analyzing the response of the optimal system under set of real earthquake ground motion records. The stochastic response behavior of the optimal system is found to be consistent with the responses obtained under real earthquake motions. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-02-07T01:32:57.360203-05:
      DOI: 10.1002/stc.1635
       
  • Robust design optimization of friction dampers for structural response
           control
    • Authors: Letícia Fleck Fadel Miguel; Leandro Fleck Fadel Miguel, Rafael Holdorf Lopez
      Pages: 1240 - 1251
      Abstract: It is known that the use of passive energy dissipation devices, as friction dampers, reduces considerably the dynamic response of a structure subjected to earthquake ground motions. However, the parameters of each damper as well as the best placement of these devices remain difficult to determine. Thus, in this paper, robust design optimization of friction dampers to control the structural response against earthquakes is proposed. In order to take into account uncertainties present in the system, some of its parameters are modeled as random variables, and consequently, the structural response becomes stochastic. To perform the robust optimization of such system, two objective functions are simultaneously considered: the mean and variance of the maximum displacement. This approach allows finding a set of Pareto‐optimal solutions. A genetic algorithm, the NSGA‐II (Nondominated Sorting Genetic Algorithm), is applied to solve the resulting multi‐objective optimization problem. For illustration purposes, a six‐story shear building is analyzed. The results showed that the proposed method was able to reduce the mean maximum displacement in approximately 70% and the variance of the maximum displacement in almost 99% with only three dampers. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-01-29T23:07:38.697258-05:
      DOI: 10.1002/stc.1642
       
  • Web‐based concrete strengthening monitoring using an innovative
           electromechanical impedance telemetric system and extreme values
           statistics
    • Authors: C. P. Providakis; E. V. Liarakos
      Pages: 1252 - 1268
      Abstract: Any possible and reliable monitoring of early age concrete strengthening can be considered as an essential aspect for operations such as removal of frameworks, prestress, or cracking control. This paper presents the development of a portable and innovative telemetric electromechanical impedance monitoring system, to experimentally monitor concrete strength development procedure from the initial states of casting and hydration to the final stages of hardening 28 days after casting. The proposed system functionality is based on piezoelectric (lead zirconate titanate) sensor/actuator technology and exploits the interaction between voltage‐stimulated piezoelectric material and host concrete structure in a coupled lead zirconate titanate concrete electromechanical system. It is found that the proposed electromechanical impedance technique associated with decision boundaries based on extreme value statistics is very sensitive to the strength gain of concrete structures from their earliest stages. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-01-29T23:26:35.944105-05:
      DOI: 10.1002/stc.1645
       
 
 
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