Damage Monitoring of a Catenary Moored Spar Platform for Renewable Energy Devices

O’Donnell, Deirdre; Murphy, Jimmy; Pakrashi, Vikram

doi:10.3390/en13143631

Cited by 9 publications

(5 citation statements)

References 60 publications

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“…The corresponding singular value is the auto-PSD function of the associated single-degree-of-freedom (SDOF) system. As the SDOF PSD evolves from a window of data that is streamed continuously over a period, an automated real-time implementation is automatically invoked [3,24]. An estimate of the SDOF correlation function is obtained by projecting the previous subset of the singular values to the time domain, using an inverse fast Fourier transform (IFFT) algorithm [24].…”

Section: Theoretical Background Of the Proposed Ae-fdd Methodsmentioning

confidence: 99%

“…Bridges are aging globally, and limited resources are available for their repair and rehabilitation. This has necessitated a need to explore automated and real-time monitoring techniques for these structures [1][2][3][4]. The Structural health monitoring (SHM) market growing rapidly [5] and vibration based SHM is a popular method in this regard.…”

Section: Introductionmentioning

confidence: 99%

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Damping estimation of a pedestrian footbridge – an enhanced frequency-domain automated approach

Bhowmik¹,

Hazra²,

O’Byrne³

et al. 2020

J. vibroeng.

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Real-time estimates of natural frequencies, mode shapes and damping of a structural system can be interpreted to its structural health. In this regard, real-time estimation of damping ratios for full-scale structures can be useful by itself or in conjunction with real-time estimates of natural frequencies. Such estimates also allow for continuous health monitoring. This paper demonstrates an approach of assessing real-time damping in full scale bridges and demonstrates this on one of the iconic steel bridges in Ireland, the Daly’s “Shaky” bridge. This is the only suspension bridge in the city of Cork, Ireland and renowned in popular culture for its lively behaviour. From existing vibration data evaluated from an image processing technique, the damping estimates of the Daly’s bridge are evaluated based on an automated enhanced frequency domain decomposition (AE-FDD) technique. The method provides accurate estimates of natural frequencies and mode shapes and additionally yields the damping ratio corresponding to each vibration (and/or torsional) mode. This technique of real-time damping estimation can be easily adapted for other full-scale structures in an automated real-time framework.

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Section: Theoretical Background Of the Proposed Ae-fdd Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Damping estimation of a pedestrian footbridge – an enhanced frequency-domain automated approach

Bhowmik¹,

Hazra²,

O’Byrne³

et al. 2020

J. vibroeng.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Scaled testing for a variety of such requirements can provide guidance not only on performance but also damage; readers are referred to [10,11] for further study.…”

Section: Sls Requirementsmentioning

confidence: 99%

Physical Modelling of Offshore Wind Turbine Foundations for TRL (Technology Readiness Level) Studies

Bhattacharya

Lombardi

Amani

et al. 2021

JMSE

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Offshore wind turbines are a complex, dynamically sensitive structure due to their irregular mass and stiffness distribution, and complexity of the loading conditions they need to withstand. There are other challenges in particular locations such as typhoons, hurricanes, earthquakes, sea-bed currents, and tsunami. Because offshore wind turbines have stringent Serviceability Limit State (SLS) requirements and need to be installed in variable and often complex ground conditions, their foundation design is challenging. Foundation design must be robust due to the enormous cost of retrofitting in a challenging environment should any problem occur during the design lifetime. Traditionally, engineers use conventional types of foundation systems, such as shallow gravity-based foundations (GBF), suction caissons, or slender piles or monopiles, based on prior experience with designing such foundations for the oil and gas industry. For offshore wind turbines, however, new types of foundations are being considered for which neither prior experience nor guidelines exist. One of the major challenges is to develop a method to de-risk the life cycle of offshore wind turbines in diverse metocean and geological conditions. The paper, therefore, has the following aims: (a) provide an overview of the complexities and the common SLS performance requirements for offshore wind turbine; (b) discuss the use of physical modelling for verification and validation of innovative design concepts, taking into account all possible angles to de-risk the project; and (c) provide examples of applications in scaled model tests.

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“…However, for pitch RAO, the angle of pitch is not adjusted for scale and so the pitch RAO amplitudes vary significantly between the full-scale and tank-scale conditions. The interpretation of pitch RAO curves should thus be aware of scaling aspects along other relevant aspects like damage [31].…”

Section: Comparisons Of Scaling Aspects For Responsementioning

confidence: 99%

Comparison of Response Amplitude Operator Curve Generation Methods for Scaled Floating Renewable Energy Platforms in Ocean Wave Basin

O’Donnell

Murphy

Pakrashi

2020

ASME Letters in Dynamic Systems and Control

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Response Amplitude Operator (RAO) curves are commonly employed to assess the dynamic behaviour of floating offshore structures in the frequency domain. There are multiple methods used to obtain RAOs for numerical models, scaled physical models and full-scale tests. While for numerical modelling many studies detail the precise methods used, the literature around experimental RAO curves often do not detail them or leave methodological information incomplete. There exists inadequate experimental evidence in assessing the differences in results obtained by following different RAO generation methods from scaled physical testing. This paper addresses this gap by comparing two most popular RAO generation methods: the Energy Spectra (ES) and the Cross Spectral Auto Spectra (CSAS) method. These are experimentally compared on scaled semi-submersible and spar buoy platforms in an ocean wave basin. Differences of heave and pitch RAOs generated by different methods are investigated. A method for reasonably collating multiple tests to create a representative RAO is also presented. RAO amplitudes vary significantly and how they decay off beyond certain frequencies is dependent on the method adopted to create them. This variation can be a source of significant uncertainty for floating structures for further analysis, design, control or repair. Some RAOs (e.g. pitch) are sensitive to scaling and should be considered when converting scaled tests to full-scale equivalent. Detailing methods of RAO generation and comparing approaches of developing them can be important for crucial decisions from scaled physical testing of floating structures at design/development stages.

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Damage Monitoring of a Catenary Moored Spar Platform for Renewable Energy Devices

Cited by 9 publications

References 60 publications

Damping estimation of a pedestrian footbridge – an enhanced frequency-domain automated approach

Damping estimation of a pedestrian footbridge – an enhanced frequency-domain automated approach

Physical Modelling of Offshore Wind Turbine Foundations for TRL (Technology Readiness Level) Studies

Comparison of Response Amplitude Operator Curve Generation Methods for Scaled Floating Renewable Energy Platforms in Ocean Wave Basin

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