Now showing 1 - 10 of 14
  • Publication
    Experimental Validation of Piezoelectric Energy-Harvesting Device for Built Infrastructure Applications
    (American Society of Civil Engineers (ASCE), 2018-06-05) ; ;
    Vibration energy-harvesting devices are increasingly becoming more efficient and useful. The performance of such devices for energy harvesting from vibrations of civil infrastructure can be theoretically quantified, and energy harvesting under harmonic loadings can be validated experimentally. Experimental validation of such devices for civil infrastructure applications, such as bridges, remains an important but more complex and challenging issue, in part due to the more uncertain nature of the dynamic response of structures under operational conditions and problems with access for such testing. Lack of existing experimental benchmarks is also a major obstacle behind adopting this technology for bridges. This study presents a laboratory-based experimental procedure through which a piezoelectric energy harvester was experimentally verified for rail bridges in their operational condition with trains traversing them. A general experimental arrangement required for validating a piezoelectric cantilever energy-harvesting device is presented, along with the fabrication of a prototype device and detailed experimental setup. A model bridge undergoing loadings from an international train fleet was chosen, and the acceleration response from the bridge was used as the excitation source for the energy-harvesting device. Numerically estimated performances of the energy harvester were validated by experimentation for a range of trains. The method is applicable for validating energy harvesting from arbitrary vibrations of built infrastructure within the laboratory environment without the need of scaling. The device and related experimental procedure will serve as a benchmark for similar unscaled tests within a laboratory environment and can be useful for assessing devices or their applications in monitoring built infrastructure under realistic conditions without the need for deployment on site.
      464Scopus© Citations 22
  • Publication
    Vibration energy harvesting based monitoring of an operational bridge undergoing forced vibration and train passage
    The application of energy harvesting technology for monitoring civil infrastructure is a bourgeoning topic of interest. The ability of kinetic energy harvesters to scavenge ambient vibration energy can be useful for large civil infrastructure under operational conditions, particularly for bridge structures. The experimental integration of such harvesters with full scale structures and the subsequent use of the harvested energy directly for the purposes of structural health monitoring shows promise. This paper presents the first experimental deployment of piezoelectric vibration energy harvesting devices for monitoring a full-scale bridge undergoing forced dynamic vibrations under operational conditions using energy harvesting signatures against time. The calibration of the harvesters is presented, along with details of the host bridge structure and the dynamic assessment procedures. The measured responses of the harvesters from the tests are presented and the use the harvesters for the purposes of structural health monitoring (SHM) is investigated using empirical mode decomposition analysis, following a bespoke data cleaning approach. Finally, the use of sequential Karhunen Loeve transforms to detect train passages during the dynamic assessment is presented. This study is expected to further develop interest in energy-harvesting based monitoring of large infrastructure for both research and commercial purposes.
      590Scopus© Citations 107
  • Publication
    Modelling and testing of a historic steel suspension footbridge in Ireland
    Daly’s Bridge is a historic steel suspension footbridge in Ireland, known locally as the ‘Shaky Bridge’ for its noticeable movement under pedestrian loading. While there is concern regarding the performance of the structure, testing or modelling have not been carried out till date and inadequate information exist in relation to carrying out such analyses. In this paper, Daly’s bridge is instrumented and tested for the first time and a model of the bridge is established and improved in the process. Apart from ambient vibration, excitation from traversing pedestrians and cyclists is considered. Video analysis of dynamic deflection, a wavelet packet based technique using acceleration responses and dynamic measurements from a cheap smartphone accelerometer application are used to identify and compare the natural frequency of the bridge. The work contributes to the evidence base of full-scale measurements of instrumenting and analysing responses of aging pedestrian bridges highlighting the complexity, challenges, opportunities and limitations related to varied levels of information available from disparate sources . The study also highlights the need of investigating to what extent cheap sensors can be successfully used as compared to their more expensive and sophisticated counterpart.
      549Scopus© Citations 14
  • Publication
    Structural health monitoring of reinforced concrete beam using piezoelectric energy harvesting system
    (INRIA Rennes - Bretagne Atlantique, 2014-07-11) ; ; ; ;
    There has been focus in recent times in the creation of smart, wireless sensor networks for the purposes of Structural Health Monitoring of large scale civil infrastructure. However, the power requirements of such networks are dependent on finite batteries, which limit the effectiveness of such a system. The use of energy harvesters, however, offers a viable and attractive solution to this problem. This paper investigates the use of such energy harvesters not only to power wireless sensor nodes, but to also act in the process as a damage detection tool. The properties and creation of such energy harvesters is detailed in full. The effects of damage on a simply supported reinforced concrete beam are investigated through finite element analysis. The use of the energy harvesters for damage detection is subsequently investigated and the feasibility of using such harvesters is experimentally validated. The simultaneous power of wireless sensor nodes by the harvesters is determined and an energy harvesting circuit is examined in this regard. This paper establishes the basis and viability of using an energy harvesting system for use in this dual role.
  • Publication
    Dynamic response signatures of a scaled model platform for floating wind turbines in an ocean wave basin
    Understanding of dynamic behaviour of offshore wind floating substructures is extremely important in relation to design, operation, maintenance and management of floating wind farms. This paper presents assessment of nonlinear signatures of dynamic responses of a scaled tension leg platform (TLP) in a wave tank exposed to different regular wave conditions and sea states characterised by the Bretschneider, the Pierson-Moskowitz, and the JONSWAP spectra. Dynamic responses of the TLP was monitored at different locations using load cells, camera based motion recognition system, and Laser Doppler Vibrometer. The analysis of variability of the TLP responses and statistical quantification of their linearity or nonlinearity, as non-destructive means of structural monitoring from output only condition, remains a challenging problem. In this study, the Delay Vector Variance (DVV) method is used to statistically study the degree of nonlinearity of measured response signals from TLP. DVV is observed to create a marker estimating the degree to which a change in signal nonlinearity reflects real time behaviour of the structure, and also to establish the sensitivity of the instruments employed to these changes. The findings can be helpful in establishing monitoring strategies and control strategies for undesirable levels or types of dynamic response, and can help better estimating changes in system characteristics over the life-cycle of the structure.
      253Scopus© Citations 30
  • Publication
    Validation of a 28-item version of the Systemic Clinical Outcome and Routine Evaluation in an Irish context: The SCORE-28
    This paper describes the development, in an Irish context, of a 3-factor, 28-item version the Systemic Clinical Outcome and Routine Evaluation (SCORE) questionnaire for assessing progress in family therapy. The 40-item version of the SCORE was administered to over 700 Irish participants including non-clinical adolescents and young adults, families attending family therapy, and parents of young people with physical and intellectual disabilities and cystic fibrosis. For validation purposes, data were also collected using brief measures of family and personal adjustment. A 28-item version of the SCORE (the SCORE-28) containing three factor scales that assess family strengths, difficulties and communication was identified through exploratory principal components analysis. Confirmatory factor analysis showed that the factor structure of the SCORE-28 was stable. The SCORE-28 and its 3 factor scales were shown to have excellent internal consistency reliability, satisfactory test-retest reliability, and construct validity. The SCORE-28 scales correlated highly with the General Functioning Scale of the Family Assessment Device, and moderately with the Global Assessment of Relational Functioning Scale, the Kansas Marital and Parenting Satisfaction Scales, the Satisfaction with Life Scale, the Mental Health Inventory – 5, and the total problems scale of the Strengths and Difficulties Questionnaire. Correlational analyses also showed the SCORE-28 scales were not strongly associated with demographic characteristics or social desirability response set. The SCORE-28 may routinely be administered to literate family members over 12 years before and after family therapy to evaluate therapy outcome.
      1201Scopus© Citations 38
  • Publication
    Psychometric properties and responsiveness to change of 15- and 28- item versions of the SCORE: A family assessment questionnaire
    The SCORE (Systemic Clinical Outcome and Routine Evaluation) is a 40-item questionnaire for completion by family members 12 years and older to assess outcome in systemic therapy. This study aimed to investigate psychometric properties of two short versions of the SCORE and their responsiveness to therapeutic change. Data were collected at 19 centers from 701 families at baseline and from 433 of these 3–5 months later. Results confirmed the three-factor structure (strengths, difficulties, and communication ) of the 15- and 28-item versions of the SCORE. Both instruments had good internal consistency and test–retest reliability. They also showed construct and criterion validity, correlating with measures of parent, child, and family adjustment, and discriminating between clinical and non clinical cases. Total and factor scales of the SCORE-15 and -28 were responsive to change over 3–5 mont hs of therapy. The SCORE-15 and SCORE-28 are brief psychometrically robust family assessment instruments which may be used to evaluate systemic therapy.
      1122Scopus© Citations 43
  • Publication
    Energy Harvesting Techniques for Health Monitoring and Indicators for Control of a Damaged Pipe Structure
    (Korea Science, 2018-03-25) ; ; ;
    Applications of energy harvesting from mechanical vibrations is becoming popular but the full potential of such applications is yet to be explored. This paper addresses this issue by considering an application of energy harvesting for the dual objective of serving as an indicator of structural health monitoring (SHM) and extent of control. Variation of harvested energy from an undamaged baseline is employed for this purpose and the concept is illustrated by implementing it for active vibrations of a pipe structure. Theoretical and experimental analyses are carried out to determine the energy harvesting potential from undamaged and damaged conditions. The use of energy harvesting as indicator for control is subsequently investigated, considering the effect of the introduction of a tuned mass damper (TMD). It is found that energy harvesting can be used for the detection and monitoring of the location and magnitude of damage occurring within a pipe structure. Additionally, the harvested energy acts as an indicator of the extent of reduction of vibration of pipes when a TMD is attached. This paper extends the range of applications of energy harvesting devices for the monitoring of built infrastructure and illustrates the vast potential of energy harvesters as smart sensors.
    Scopus© Citations 18  240
  • Publication
    Energy harvesting from train-induced response in bridges
    The integration of large infrastructure with energy-harvesting systems is a growing field with potentially new and important applications. The possibility of energy harvesting from ambient vibration of bridges is a new field in this regard. This paper investigates the feasibility of energy harvesting for a number of trains considering their passage over a bridge. The power that can be derived from an energy-harvesting device due to a train crossing a bridge at different speeds is compared against typical demands of small wireless devices and is found to be adequate for powering such devices. These estimates of harvested energy also relate to the individual signatures of trains. In this work, the modeled dynamic responses of a bridge traversed by trains are compared against full-scale experimental analysis of train-bridge interactions. A potential application in structural health monitoring (SHM) using energy harvesting has also been demonstrated and compared with laboratory experimental data. Consistent and monotonic damage calibration curves have been constructed using estimated harvested energy.
      580Scopus© Citations 82
  • Publication
    Effect of Road Surface, Vehicle, and Device Characteristics on Energy Harvesting from Bridge–Vehicle Interactions
    Energy harvesting to power sensors for structural health monitoring (SHM) has received huge attention worldwide. A number of practical aspects affecting energy harvesting and the possibility of health monitoring directly from energy harvesters is investigated here. The key idea is the amount of power received from a damaged and an undamaged structure varying and the signature of such variation can be used for SHM. For this study, a damaged bridge and an undamaged bridge are considered with harvesters located at different positions and the power harvested is accessed numerically to determine how energy harvesting can act as a damage detector and monitor. Bridge–vehicle interaction is exploited to harvest energy. For a damaged bridge, a bilinear breathing crack is considered. Variable surface roughness according to ISO 8606:1995(E) is considered such that the real values can be considered in the simulation. The possibility of a drive-by type health monitoring using energy harvesting is highlighted and the effects of road surface on such monitoring are identified. The sensitivity of the harvester health monitoring to locations and extents of crack damage are reported. This study investigates the effects of multiple harvesters and the effects of vehicular parameters on the harvested power. Continuous harvesting over a length of the bridge is considered semianalytically. A comparison among the numerical simulations, detailed finite element analysis, and experimental results emphasizes the feasibility of the proposed method.
      578Scopus© Citations 37