Component reliability test approaches for marine renewable energy

Thies, Philipp R.; Johanning, Lars; Karikari-Boateng, Kwaku Ampea; Ng, Chong; McKeever, Paul

doi:10.1177/1748006x15580837

Cited by 6 publications

(8 citation statements)

References 46 publications

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“…10 Improving reliability is one of the key areas that can deliver these cost reductions through increased availability (and hence yield) and reduced operation and maintenance costs. 11 Reliability is often seen as a key risk for the commercial development of OECs, as it directly impacts investment decisions. Considerable investment is necessary to build the required prototypes and fund the development programmes to improve the reliability and hence reduce the risks.…”

Section: Performance and Reliability Test Methodsmentioning

confidence: 99%

Performance and reliability testing of an active mooring system for peak load reduction

Luxmoore

Thies

Grey³

et al. 2018

Proceedings of the IMechE

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Offshore renewable energy systems are generally required to operate in exposed offshore locations for long deployment periods at low cost. This requires innovative new mooring system solutions to go beyond the existing offshore industry designs. A number of novel mooring systems have recently been proposed which decouple mooring line compliance and minimum breaking load, offering multiple benefits to designers. Demonstrating reliability for such highly novel systems where standards do not yet exist is a common problem both for mooring systems specifically and in offshore renewable applications generally. A performance and reliability test method is proposed here and is applied to a novel mooring system, the Intelligent Active Mooring System. The line stiffness and damping properties of Intelligent Active Mooring System can be optimised to the prevailing metocean conditions without compromising minimum breaking load; the pre-tension is also adjustable for tidal range compensation or for service access. The article presents the results of a feasibility study for Intelligent Active Mooring System including detailed, large-scale physical performance tests that demonstrate load reductions under normal operating and extreme sea state conditions. The rationale and findings for an accelerated reliability test regime that quantifies the ultimate load capacity of the component and gives insight into the governing failure modes are also presented. The presented test approach provides assurance for the overall system integrity.

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Section: Performance and Reliability Test Methodsmentioning

confidence: 99%

Performance and reliability testing of an active mooring system for peak load reduction

Luxmoore

Thies

Grey³

et al. 2018

Proceedings of the IMechE

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“…The rig can test component specimens of up to 6 meters in length and has the capability of carrying out immersed component testing. The linear actuator and the headstock allow the dynamic testing of large scale components in a fully-controlled environment by applying realistic motion and load time-series [18].…”

Section: Test Facility and Tensile Load Profilementioning

confidence: 99%

Underwater acoustic emission monitoring – Experimental investigations and acoustic signature recognition of synthetic mooring ropes

et al. 2017

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Mooring ropes are essential components of offshore installations, and synthetic ropes are increasingly preferred because of their favourable cost to weight ratios. In-service condition of these materials is traditionally monitored through costly visual inspection, which adds to the operating costs of these structures. Acoustic Emissions (AE) are widely used for condition-monitoring in air, and show great potential underwater. This paper investigates the AE signatures of synthetic mooring ropes subjected to sinusoidal tension-tension loading in a controlled environment, using a large-scale dynamic tensile test rig. With a linear array of 3 broadband (20 Hz-50 kHz) hydrophones, four main signatures are identified: low-to high frequency, low-amplitude signals (50 Hz-10 kHz), lowamplitude broadband signals (10 kHz-20 kHz), high amplitude signals (10 Hz-48 kHz) and mediumamplitude signals (500 Hz-48 kHz). These AE types are related to different stages of rope behaviour, from bedding-in to degradation and failure. The main findings are that the failure location and breaking load can be identified through the detection of AE. The occurrence of high amplitude AE bursts in relation to the applied tensile load allows the detection of an imminent failure, i.e. prior to the failure event. These initial results indicate that AE analyses can enable the integrity of synthetic mooring ropes to be monitored.

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“…Subsea components such as those used in mooring systems (e.g., [22]), risers and cables (e.g., [23]) are prime examples of components which require testing prior to use. These components have to be highly reliable to be fit for purpose (i.e., to ensure that the device is kept on station in the case of mooring components), whilst being cost-effective.…”

Section: Testing Facilities: the South West Mooring Test Facility (Swmentioning

confidence: 99%

Reducing Reliability Uncertainties for Marine Renewable Energy

Weller

Thies

Gordelier

et al. 2015

JMSE

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Technology Readiness Levels (TRLs) are a widely used metric of technology maturity and risk for marine renewable energy (MRE) devices. To-date, a large number of device concepts have been proposed which have reached the early validation stages of development (TRLs 1-3). Only a handful of mature designs have attained pre-commercial development status following prototype sea trials (TRLs 7-8). In order to navigate through the aptly named "valley of death" (TRLs 4-6) towards commercial realisation, it is necessary for new technologies to be de-risked in terms of component durability and reliability. In this paper the scope of the reliability assessment module of the DTOcean Design Tool is outlined including aspects of Tool integration, data provision and how prediction uncertainties are accounted for. In addition, two case studies are reported of mooring component fatigue testing providing insight into long-term component use and system design for MRE devices. The case studies are used to highlight how test data could be utilised to improve the prediction capabilities of statistical reliability assessment approaches, such as the bottom-up statistical method.

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Component reliability test approaches for marine renewable energy

Cited by 6 publications

References 46 publications

Performance and reliability testing of an active mooring system for peak load reduction

Performance and reliability testing of an active mooring system for peak load reduction

Underwater acoustic emission monitoring – Experimental investigations and acoustic signature recognition of synthetic mooring ropes

Reducing Reliability Uncertainties for Marine Renewable Energy

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