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A Probabilistic Fracture Mechanics Based Approach for Inspection Planning of Offshore Wind and Hydrogen Jacket Structures

Shafiee, Mahmood (2022) A Probabilistic Fracture Mechanics Based Approach for Inspection Planning of Offshore Wind and Hydrogen Jacket Structures. In: 11th European Solid Mechanics Conference (ESMC 2022), 04-08 Jul 2022, Galway, Ireland. . (In press) (Access to this publication is currently restricted. You may be able to access a copy if URLs are provided) (KAR id:95540)

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Abstract

A safe, efficient and economical design, construction and operation of jacket structures is crucial for the development of net-zero energy projects. Jacket structures are one of the most important structures in offshore wind and hydrogen production. These structures should be designed with sufficient strength and stiffness to withstand the forces to which they may be subjected in harsh and adverse environments and weather conditions. A jacket structure is a welded tubular space frame consisting of three or more near-vertical legs supported by a lateral bracing system. The welded tubular joints are among the most critical members of the structure that suffer from severe fatigue stresses caused by cyclic wind and wave loading. An effective way to prolong the useful life of jacket structures while minimizing their associated repair costs is to develop and implement a robust inspection regime throughout the operation. In this research, we propose an optimal inspection planning based on probabilistic fracture mechanics models for offshore jacket structures subject to fatigue conditions. The fatigue crack growth behaviour of welded connections over time are modelled by an extended Paris’s law formulation and then the probability of a structural failure is predicted by means of a Monte Carlo Simulation (MCS). For a range of reliability threshold values, various inspection plans are produced and their performance in terms of life-cycle cost (including the costs related to fatalities and serious injuries, damage to assets, inspection and repair, and loss of production due to downtimes) is assessed. A minimum-cost inspection strategy throughout the jacket’s lifetime is obtained and the results are compared with the currently used constant-interval inspections. In order to illustrate the use of the model, it is applied to a four-legs steel jacket structure and an optimal inspection schedule for two of its welded joints is determined. It is found that the use of the proposed model not only minimizes the repair costs but also ensures safe operation of the structure during its entire life span. Finally, a sensitivity analysis is conducted to evaluate the effect of stress levels on the optimum inspection schedule.

Item Type: Conference or workshop item (Paper)
Uncontrolled keywords: Fracture Mechanics; Inspection; Offshore Jacket Structures
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA401 Materials engineering and construction
T Technology > TJ Mechanical engineering and machinery
Divisions: Divisions > Division of Computing, Engineering and Mathematical Sciences > School of Engineering and Digital Arts
Depositing User: Mahmood Shafiee
Date Deposited: 25 Jun 2022 20:10 UTC
Last Modified: 09 Jul 2022 12:41 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/95540 (The current URI for this page, for reference purposes)

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