Volume 3: Structures, Safety, and Reliability最新文献

{"title":"Experimental Assessment of Form Based Approach for Predicting Extreme Value Distribution of Hull Girder Bending Moment in a Ship","authors":"Tomoki Takami, Yusuke Komoriyama, T. Ando, K. Iijima","doi":"10.1115/omae2019-95389","DOIUrl":"https://doi.org/10.1115/omae2019-95389","url":null,"abstract":"\u0000 This paper describes a series of towing tank tests using a scaled model of a recent container ship for validating the First Order Reliability Method (FORM) based approach to predict the maximum response. The FORM based approach is adopted in conjunction with the nonlinear strip method as an estimation method for the most probable wave episodes (MPWEs) leading to the given extreme wave-induced vertical bending moments (VBMs). Tank tests under the pre-determined MPWEs are conducted to evaluate the extreme wave-induced VBMs. Numerical simulations based on the coupled Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) are also conducted and are compared with the test results under the MPWEs. Furthermore, to estimate the extreme VBM statistics, tank tests under random irregular waves are conducted. A series of validations of the probability of exceedances (PoEs) of the VBM evaluated from the FORM based approach is carried out. The effect of hydroelastic (whipping) vibrations on the extreme VBM statistics are finally discussed.","PeriodicalId":314553,"journal":{"name":"Volume 3: Structures, Safety, and Reliability","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124969636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asset Integrity Control: Prioritization of Offshore Topside Flange Openings During Preventive Maintenance Shutdowns","authors":"R. Ratnayake","doi":"10.1115/omae2019-96576","DOIUrl":"https://doi.org/10.1115/omae2019-96576","url":null,"abstract":"\u0000 Top side flange inspection on offshore production and process facilities (P&PFs) has been a challenging task, due to complex geometries, produced crude oil and gas quality changes over the production well’s maturity, as well as the stringent regulatory requirements that need to be followed to assure the anticipated integrity of the operating assets. The complex geometries hinder the use of non-destructive testing (NDT) testing approaches and necessitate shutting down the system or subsystem in order to disassemble the flange to perform close visual inspection (CVI). Using risk-based asset integrity (AI) assessment and control (RBAIA&C) approaches, it is possible to classify the flanges into different classes, according to probability of failure (PoF). The PoF is estimated by considering the last inspection date, past inspection data, findings from similar locations/systems in the same offshore facility, etc. Together with consequence of potential failures (CoF), it is possible to estimate the risk of a potential failure due to the loss of integrity of a selected flange. Although several flanges are qualified to be disassembled, based on RBAIA&C activities, it is not possible to take all of them off during a certain preventive maintenance (PM) shutdown. Currently, ad hoc approaches have been used to further prioritize the flanges that have been recommended for inspection during a PM shutdown, based on RBAIA&C activities. The aforementioned jeopardizes the integrity of flanges and subsequently the overall system, possibly leading to catastrophic accidents. This manuscript demonstrates a methodology for the systematic further prioritization of flanges that need routine CVI. The flange inspection related system analytics have been incorporated with the analytic hierarchy process (AHP) to make logical further prioritization with sufficient transparency. The approach has been demonstrated with an illustrative case study that has been chosen from an offshore P&PF. A sensitivity analysis has also been performed and is presented to demonstrate how to carry out trade-off evaluations between different factors in the flange prioritization in a PM shutdown.","PeriodicalId":314553,"journal":{"name":"Volume 3: Structures, Safety, and Reliability","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124041325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear Airy Wave Pulses on the Sea Surface","authors":"I. Shugan, S. Kuznetsov, Y. Saprykina, Yang-Yih Chen","doi":"10.1115/omae2019-96298","DOIUrl":"https://doi.org/10.1115/omae2019-96298","url":null,"abstract":"\u0000 The possibility of self-acceleration of the water-wave pulse with a permanent envelope in the form of the nonlinear Airy function during its long propagation in deep water is experimentally and theoretically analyzed. This wave packet has amazing properties — accelerates without any external force, and preserves shape in a dispersive medium. The inverted Airy envelope wave function can propagate at velocity that is faster than the group velocity. We experimentally study the behavior of Airy water-wave pulses in a super-tank and long scaled propagation, to investigate its main properties, nonlinear effects and stability. Theoretical modeling analysis is based on the nonlinear Schrodinger equation. We investigate the scope of applicability, feasibility and stability conditions of nonlinear Airy wave trains in the deep water conditions; defining regimes of self-acceleration of the main pulse, immutability shape of Airy envelope; assessing the impact of nonlinearity and dissipation on the propagation of Airy waves. We analyzed the influence of the initial pulse characteristics on self-acceleration of wave packet and the stability of the envelope form. The anticipated results allow extending the physical understanding of the evolution of nonlinear dispersive waves in a wide range of initial conditions and at different spatial and temporal scales, from both theoretical and experimental points of view. Steep waves start to become an unstable, we observe spectrum widening and downshifting. Wave propagation is accompained by the intensive wave breaking and the generation of water-wave solitons.","PeriodicalId":314553,"journal":{"name":"Volume 3: Structures, Safety, and Reliability","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127499093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of an Equivalent Design Wave Method to Define Lifetime Combined Loading Scenarios for Trimarans","authors":"H. Seyffert, A. Kana","doi":"10.1115/omae2019-95497","DOIUrl":"https://doi.org/10.1115/omae2019-95497","url":null,"abstract":"\u0000 The evaluation of marine system reliability requires the definition of the most extreme loading that a vessel is expected to experience. To quantify the risk levels associated with a full ship lifetime, some decisions must be made about which vessel scenarios are worth analyzing, i.e. the worst-case vessel scenarios. The problem is further complicated when considering extreme combined loading on a novel hull form such as a trimaran. To evaluate structural compliance with given acceptance criteria many classification societies suggest defining simultaneous load combination cases by an Equivalent Design Wave (EDW) method for use in a finite element model. This paper examines whether the EDW approach defines realistic lifetime combined loading scenarios specifically for a novel hull form like a trimaran.","PeriodicalId":314553,"journal":{"name":"Volume 3: Structures, Safety, and Reliability","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125399898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Monte Carlo Based Simulation Method for Damage Stability Problems","authors":"S. Krüger, Hendrik Dankowski","doi":"10.1115/omae2019-95295","DOIUrl":"https://doi.org/10.1115/omae2019-95295","url":null,"abstract":"\u0000 To cope with future developments of the SOLAS 2009 B1, damage stability investigations must become a central part of the initial design phase. If damage stability calculations are performed in the classical way, they are very time consuming with respect to both modelling and computational time. To overcome this problem, damage stability can be treated as a stochastic process, where the probability of a damage case and the survivability of that particular damage case need to be determined. This task can be solved by direct numerical simulations based on the Monte Carlo principle. If statistical damage distributions are once known, the Monte Carlo simulation delivers a population of damages which can be automatically related to certain damage cases. These damage cases can then be investigated with respect to their survivability.\u0000 Applying this principle to SOLAS 2009 damage stability calculations leads to a number of implementation problems which must be solved to guarantee that the MC simulation delivers exactly the same results as the manual, zone based damaged stability calculation. If these problems are solved, the MC based damage stability calculations can be used during the initial design phase until the damage stability approval. The proposed method reduces the computational effort drastically which supports the initial design phase of the ship’s compartmentation. The method further leads to higher attained indices and consequently to a safer and more efficient design.","PeriodicalId":314553,"journal":{"name":"Volume 3: Structures, Safety, and Reliability","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123843932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysing Dependent Failures in a Bayesian Belief Network","authors":"M. Fam, D. Konovessis, Xuhong He, L. S. Ong, H. K. Tan","doi":"10.1115/omae2019-95853","DOIUrl":"https://doi.org/10.1115/omae2019-95853","url":null,"abstract":"\u0000 Fault trees (FT) and event trees (ET) have been used thoroughly in risk analysis and there have been a few published articles outlining how to map FTs and ETs to Bayesian Belief Networks (BBN). There have been documented benefits of a BBN being able to consider Common Cause Failures (CCF) and conditional dependencies. With modelling CCFs in a BBN, there is a possibility to increase the level of analysis of a CCF by breaking down the analysis to the respective CCF Categories, such as Environment, Maintenance or Design. This allows a better understanding of the contributing events given a defined accident scenario. Also, in the decommissioning industry, there is no established database yet for CCF of components, as decommissioning projects are sparse and spread out across different operating conditions. Hence it may be practical to adjust generic CCFs to obtain facility-specific parameters for common cause failures. The paper thus highlights how to express CCFs with a Beta-Factor Model in a BBN and by extension, undertake an extended level of analysis according to CCF categories and adjust generic database common cause factors to a facility-specific factor based on a checklist. The technique is applied to a risk analysis of a well plugging and abandonment event.","PeriodicalId":314553,"journal":{"name":"Volume 3: Structures, Safety, and Reliability","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124913306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Subsea Spare Parts Analysis Optimisation","authors":"T. Coffey, C. Rai, J. Greene, Stephen O’Brien Bromley","doi":"10.1115/omae2019-96100","DOIUrl":"https://doi.org/10.1115/omae2019-96100","url":null,"abstract":"\u0000 The main objective of this paper is to present a fully quantitative methodology combining reliability, availability and maintainability (RAM) analysis and cost-benefit analysis (CBA) approaches to determine the optimum sparing strategy for subsea components considering reliability data, lead times, availability and cost. This methodology can be utilized at any stage of an asset lifecycle, from design to operation and can be adjusted to reflect modifications throughout the life of field.\u0000 Using commercially available RAM analysis software, Maros [2], a reliability block diagram (RBD) is constructed to represent the reliability structure and logic of the system being analyzed. Retrievable components, for which spares would be suitable, are then identified within the model to review and update the failure modes and reliability information for each component. Reliability information can be based on project specific data or from industry-wide sources such as OREDA. The RAM analysis software uses the Monte-Carlo simulation technique to determine availability. A sensitivity analysis is then performed to determine maximum availability while holding the minimum required stock level of spare components.\u0000 A sparing priority factor (SPF) analysis is then performed in addition to the RAM sensitivity analysis to support those results and consider spare purchase, storage and preservation costs. The SPF gives a weighting to the storage cost against the potential impact on production. The SPF is a number used to determine a component’s need to have a spare. A high SPF indicates an increased requirement to hold a spare.","PeriodicalId":314553,"journal":{"name":"Volume 3: Structures, Safety, and Reliability","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129965289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tethered BOP Stacks: Performance and Monitoring","authors":"S. Killbourn, E. Kebadze, J. Maher","doi":"10.1115/omae2019-95523","DOIUrl":"https://doi.org/10.1115/omae2019-95523","url":null,"abstract":"\u0000 Subsea wells present challenges for fatigue utilisation throughout the life of these high-value assets. New wells may be constructed at seabed locations where soil properties may be unfavourable or uncertain. Existing wells may require workover and eventual abandonment. This can lead to relatively small conductors supporting higher BOP masses than was envisaged when these wells were constructed. To address such stability issues during drilling and work-over operations, a BOP stack may be tethered to seabed anchors to provide lateral retention. The increased foundation stiffness raises the BOP characteristic frequency which suppresses motion of the BOP and significantly reduces fatigue of the conductor and wellhead. Real-time monitoring of the tether tensions and BOP characteristic frequency provide on-going verification of the efficacy of this fatigue suppressing technology as well as tracking structural integrity. For example, the ability of the monitoring system to detect loss of tether tension and the success of ROV intervention to reapply tension is demonstrated.","PeriodicalId":314553,"journal":{"name":"Volume 3: Structures, Safety, and Reliability","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121222157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Benchmarking Exercise on Estimating Extreme Environmental Conditions: Methodology and Baseline Results","authors":"Andreas F. Haselsteiner, R. Coe, L. Manuel, P. Nguyen, Nevin Martin, A. Eckert-Gallup","doi":"10.1115/omae2019-96523","DOIUrl":"https://doi.org/10.1115/omae2019-96523","url":null,"abstract":"\u0000 A wide range of methods have been proposed for the derivation of environmental contours for marine structures that must meet reliability targets. An environmental contour is a set of joint extremes of environmental conditions associated with a target return period. In general, environmental contour methods help with the prediction of some future critical combinations of environmental conditions (e.g., wind, waves, current) at a location of interest based on a limited dataset, thus allowing designers to ensure a prescribed structural reliability. In fact, some of these contour methods are specifically recommended by technical specifications and standards as part of a design process. This paper outlines the rules and procedures for a collaborative benchmarking exercise — focused on open comparison — in which researchers are invited to develop and present their own contour derivation approaches based on common datasets that will be available to all. Hindcast and observational datasets are considered and two exercises are planned: One focuses on applying environmental contour methods to a wide range of datasets and the other focuses on uncertainty characterization. Besides describing the benchmark’s methodology, this paper presents baseline results of computed contours following current recommendations. The overall goals of this endeavor are: (i) to work towards the development of more robust statistical models and contour construction methods, (ii) to encourage increased discussion in the international research community and among practitioners, and (iii) to support ongoing efforts to improve technical specifications and standards.","PeriodicalId":314553,"journal":{"name":"Volume 3: Structures, Safety, and Reliability","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128120141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a New, Correlated FEA Method of Assessing Mooring Chain Fatigue","authors":"Gary H. Farrow, A. Potts, A. Kilner, P. Kurts, Simon Dimopoulos, Eric N Jal","doi":"10.1115/omae2019-95882","DOIUrl":"https://doi.org/10.1115/omae2019-95882","url":null,"abstract":"The first phase of the Chain FEARS (Finite Element Analysis of Residual Strength) Joint Industry Project (JIP) aimed to develop guidance for the determination of a rational discard criteria for mooring chains subject to severe pitting corrosion which, based on current code requirements, would otherwise require immediate removal and replacement. Critical to the ability to evaluate the residual fatigue life of a degraded chain, is to have an accurate estimate of the chain in its as-new condition, thereby providing a benchmark for any loss in fatigue life associated with severe corrosion or wear.\u0000 A large collection of fatigue test data was collated for comparison and to establish underlying trends in as-new mooring chain fatigue response. A non-linear multi-axial Finite Element Analysis (FEA) fatigue assessment method was developed to correlate against available as-new chain link fatigue test data and underlying failure trends as part of the JIP achieving this critical requirement.\u0000 It was established that the linear FEA fatigue method currently employed in the industry is too simplistic and does not correlate with the fatigue test data, whereas an alternative method of assessing fatigue based on FEA, developed with respect to the DNV B1 material curve, correlates well with the available physical fatigue test data.\u0000 The FEA method uses a non-linear chain link FEA and multi-axial stress fatigue calculation method to determine an equivalent Stress Magnification Factor (SMF). This method achieves good correlation of predicted utilisations and associated cycles-to-failure with fatigue test data and in respect of critical locations with evidenced failure locations. The method of equivalent SMF calculation accounted for the significant effects on fatigue performance including proof load induced residual stress, mean stress levels and the increase in material fatigue endurance associated with increased steel UTS (i.e. increased offshore mooring chain grade). The analytical method developed in this study achieved a high degree of correlation with as-new chain fatigue test data, and should enable the accurate prediction of fatigue stresses around a link and in particular for irregular geometry associated with corrosion degraded chain links.","PeriodicalId":314553,"journal":{"name":"Volume 3: Structures, Safety, and Reliability","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133499483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}