Now showing 1 - 10 of 14
- PublicationLaboratory based experimental investigation of patch based piezoelectric energy harvesters for civil infrastructureVibration energy harvesting technology applications for civil infrastructure has received significant interest in recent times. This is due to the advantages that are associated with power independent, output only energy harvesters which have the potential to act as either the power supply to low-power wireless sensors or as power independent sensors. Studies into the deployment of such harvesters with civil infrastructure applications have shown a potential range of applications ranging including high-rise buildings, pipelines, bridge infrastructure and wind turbine structures. While there can be immense cost associated with validation of energy harvesters through full-scale testing with civil infrastructure, laboratory based validation provides an inexpensive method of validating specific vibration energy harvesting devices with individual structures. By applying available datasets of vibrational response of civil infrastructure to the device using the shaker unit, the individual devices may be tested for realistic excitation conditions without any scaling of the structures vibrational response being required. This paper considers the use of laboratory based testing procedures for the experimental validation of patch based energy harvesters. The theoretical performance of the harvester for a model bridge undergoing train loadings is determined and the performance using measured datasets from full scale testing for train bridge interaction is similarly shown. An experimental setup is created to experimentally test the energy harvesters and the results of the experimental results versus the theoretical expectations are compared. This paper helps further establish the importance of laboratory based testing for vibration energy harvesters with civil infrastructure applications.
- PublicationStructural health monitoring of reinforced concrete beam using piezoelectric energy harvesting systemThere 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.
- PublicationExperimental Validation of Piezoelectric Energy-Harvesting Device for Built Infrastructure ApplicationsVibration 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.
363Scopus© Citations 16
- PublicationModelling and testing of a historic steel suspension footbridge in IrelandDaly’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.
407Scopus© Citations 12
- PublicationChild maltreatment and adult psychopathology in an Irish contextOne-hundred-ninety-nine adult mental health service users were interviewed with a protocol that included the Childhood Trauma Questionnaire, the Structured Clinical Interviews for Axis I and II DSM-IV disorders, the Global Assessment of Functioning scale, the SCORE family assessment measure, the Camberwell Assessment of Need Short Appraisal Schedule, and the Readiness for Psychotherapy Index. Compared to a U.S. normative sample, Irish clinical cases had higher levels of maltreatment. Cases with comorbid axis I and II disorders reported more child maltreatment than those with axis I disorders only. There was no association between types of CM and types of psychopathology. Current family adjustment and service needs (but not global functioning and motivation for psychotherapy) were correlated with a CM history. It was concluded that child maltreatment may contribute to the development of adult psychopathology, and higher levels of trauma are associated with co-morbid personality disorder, greater service needs and poorer family adjustment. A history of child maltreatment should routinely be determined when assessing adult mental health service users, especially those with personality disorders and where appropriate evidence-based psychotherapy which addresses childhood trauma should be offered.
477Scopus© Citations 5
- PublicationPsychometric properties and responsiveness to change of 15- and 28- item versions of the SCORE: A family assessment questionnaireThe 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.
754Scopus© Citations 36
- PublicationVibration energy harvesting based monitoring of an operational bridge undergoing forced vibration and train passageThe 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.
334Scopus© Citations 81
- PublicationHorizontal loading effects of fresh concrete on precast archesThis paper investigates the horizontal effect of fresh concrete on precast arches. A number of different models of horizontal pressure of fresh concrete are considered in this regard. The effects of fresh concrete on a precast arch are represented as a ratio of maximum normal stress from horizontal action of fresh concrete to the normal stress induced by the self-weight of the precast concrete arch. A parameter study on a number of geometric and operational variables was carried out. The implications of this horizontal loading from fresh concrete are discussed within the context of the potential financial effects.
- PublicationEnergy harvesting from train-induced response in bridgesThe 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.
438Scopus© Citations 70
- PublicationValidation of a 28-item version of the Systemic Clinical Outcome and Routine Evaluation in an Irish context: The SCORE-28This 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.
1118Scopus© Citations 37