Volume 2B: Structures, Safety, and Reliability最新文献

{"title":"Sensitivity Study About Ultimate Strength and Postbuckling Behavior of Stiffened Box Deck Girder Under Compression","authors":"C. Zhou, D. Song","doi":"10.1115/omae2020-18580","DOIUrl":"https://doi.org/10.1115/omae2020-18580","url":null,"abstract":"\u0000 The proper determination of this paper is to study the ultimate strength and postbuckling behavior for complicated stiffened deck girders of offshore platforms. Normally, offshore platforms are designed with reinforcing stiffeners on box deck girder.\u0000 The box deck of column stabilized platform will be simulated with FEM software ABAQUS. Linear eigenvalue analysis is firstly applied to introduce the initial imperfection into the structure. Then the non-linear postbuckling analysis for the box deck girder will illustrate ultimate strength and the failure mode under axial load after collapse. The ways how the stiffeners, eigenmode and imperfections influence the ultimate capacity will also be analyzed.\u0000 Comparing variable elements affecting the structural strength, the work shows the offshore box deck girder section from the engineering project in this paper is quite robust to the axial compression. For this kind of robust design, such as the box deck girder, the eigenmode selection and amplitude of imperfection will exert slight effects on the ultimate strength, but the severe imperfections will accelerate the local buckling. Stiffeners design will exert dramatic influence on the ultimate strength and postbuckling behaviors. And the work to find the optimum balance among structural strength variable load and allowable imperfections seems to be very promising in engineering. The conclusions provide a more clear insight into the further optimization of the offshore square structure design.","PeriodicalId":191387,"journal":{"name":"Volume 2B: Structures, Safety, and Reliability","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127531369","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":"Integrated Probabilistic-Mechanistic Deterioration Modeling for Preventive Maintenance of Aging Fixed Offshore Jacket-Type Platforms","authors":"I. Srikanth, M. Arockiasamy","doi":"10.1115/omae2020-18927","DOIUrl":"https://doi.org/10.1115/omae2020-18927","url":null,"abstract":"\u0000 Most of the offshore platforms in the world are designed as steel jacket-type platforms for oil and gas exploration and production. A significant amount of research has been carried out over the past two decades to understand ageing and the associated degradation of offshore structural members. The paper proposes an approach for prioritization and preventive maintenance of jacket-type platform. Offshore platform maintenance systems are dependent on deterioration models to predict the future condition of structural elements. The input for these models consists of condition states of different jacket elements and their evolution as a function of time. One of the challenges includes lack of availability of condition state records for the aging platforms. This paper proposes a methodology for developing deterioration models when there is a scarcity of inspection records.\u0000 This study focusses on developing a methodology for i) the impact ranking of different bracing member groups of the jacket platform and ii) deterioration models using integrated probabilistic-mechanistic modeling. Firstly, a typical jacket-type offshore platform under the North Sea conditions is modeled and analyzed under wave and current loads. Then, nonlinear static (pushover) analyses are performed for the undamaged jacket platform. The criticality of the different groups of bracing elements is obtained in terms of Residual Resistance Factor by carrying-out redundancy analyses. Soil-structure interaction effect is considered in the analyses and the results are compared with the hypothetical fixed-support end condition. The member groups are then ranked based on their impact on the ultimate strength of the jacket platform. Secondly, deterioration models for jacket legs and bracings in splash and immersion zones are obtained based on integrated mechanistic-probabilistic approach. An idealized uniform corrosion model is used in generating the member condition state probabilities. Condition state probabilities for jacket legs and bracings are then generated using Monte Carlo simulations. The residual service life of the jacket elements is predicted from the deterioration models which could be utilized for preventive maintenance of the jacket platform.","PeriodicalId":191387,"journal":{"name":"Volume 2B: Structures, Safety, and Reliability","volume":"186 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122673068","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":"Real Time Monitoring of Subsea Well Foundation Integrity","authors":"David Bolger, Stuart Kilbourn, J. Crombie, Steven Kidd","doi":"10.1115/omae2020-18210","DOIUrl":"https://doi.org/10.1115/omae2020-18210","url":null,"abstract":"\u0000 Production wells have been constructed in an area offshore which is known for having localised deposits of very soft soil close to mudline. During well planning, it was identified that two other operators had attempted to drill in the region but had to suspend or abandon the well due to excessive degradation of the soil supporting the well foundation. The objective of this work was to provide real-time wellhead integrity data to support the well management team during operations.\u0000 The real-time monitoring system was deployed on a subsea BOP stack and riser during drilling and completion operations to monitor motions. From the recorded signals, wellhead integrity was inferred by determining the BOP stack characteristic frequency and effective fixity depth. These integrity parameters were relayed to the vessel via a hydroacoustic link and then delivered onshore. An automatic alarm system was setup based on pre-defined limits which would be triggered during operations if the integrity of the well foundation became at risk of permanent damage. Additionally, the BOP stack motion data allowed the accumulated fatigue damage to be tracked.\u0000 The alarm system provided a regular 15-minute check on the integrity of the wellhead and conductor system. If advisory limits were triggered, the well management team were able to assess weather forecasts and make an informed decision to continue drilling or to disconnect from the wellhead to avoid a period of rough weather. This would prevent excessive degradation of the soil and protect the integrity of the well. When increased BOP motions were observed by the drilling team, operations were able to continue with confidence because the integrity data remained within acceptable limits. This avoided unnecessary downtime, providing significant savings in both cost and rig-time as well as improving the overall safety profile of the operation.","PeriodicalId":191387,"journal":{"name":"Volume 2B: Structures, Safety, and Reliability","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132583068","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":"Numerical Simulation of Dynamic Response of Foam Aluminum Sandwich Panel Under Impact Load","authors":"W. Wan, Li Xiaobin, Li Jiang, L. Pu","doi":"10.1115/omae2020-18276","DOIUrl":"https://doi.org/10.1115/omae2020-18276","url":null,"abstract":"\u0000 The impact resistance of protective structure directly affects the vitality of the ship. Since the excellent energy absorption characteristics and lightweight structural forms, foamed aluminum sandwich panels have gradually replaced stiffened panels and are widely used in local structures and components of vessels. In order to improve the protective ability of the ship structure, the impact resistance of the foam aluminum sandwich panel is studied in this paper. The deformation mechanism of the foam aluminum sandwich panel under the impact of the foam aluminum projectile is simulated by the finite element analysis, and the effect of different core thickness and core strength on the dynamic response of the sandwich panel is studied. An optimized structural form is proposed for the shear failure of foam aluminum sandwich panels. The results show that the optimized structure improves the impact resistance of foam aluminum sandwich panel and the shear resistance of the intermediate core layer. The research of this paper provides reference for the optimization of foam metal sandwich structure and its application in ship protection structure.","PeriodicalId":191387,"journal":{"name":"Volume 2B: Structures, Safety, and Reliability","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127640150","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":"Hydrodynamic Optimization of a Containership","authors":"Yanxin Feng, O. E. Moctar, T. Schellin","doi":"10.1115/omae2020-18616","DOIUrl":"https://doi.org/10.1115/omae2020-18616","url":null,"abstract":"\u0000 Using open-source software Dakota, this paper describes the process of generating an optimal parametric hull shape for a generic containership. Selected design variables defined the ship’s hull, and the influence of these variables on calm water resistance was analyzed. Computations of the flow around the hull were obtained from a validated nonlinear potential flow boundary element method. Using the multi-objective optimization algorithm Surrogate Based Global Optimization (SBGO) reduced the computational effort. The hydrodynamic calm water ship resistance defined the objective function. Compared with the original hull, wave resistance of the optimal hull was significantly reduced for the ship at Froude numbers corresponding to its design speeds.","PeriodicalId":191387,"journal":{"name":"Volume 2B: Structures, Safety, and Reliability","volume":"238 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115753395","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":"Risk Based Integrity Assessment and Life Extension Procedure for Subsea Wellhead Connectors","authors":"G. Sigurdsson, T. Hørte, M. Macke, A. Wormsen, L. Reinås","doi":"10.1115/omae2020-19330","DOIUrl":"https://doi.org/10.1115/omae2020-19330","url":null,"abstract":"\u0000 Subsea Wellheads are the male part of an 18 3/4” bore connector used for connecting subsea components such as drilling BOP, XT or Workover systems equipped with a female counterpart — a wellhead connector. Subsea wellheads have an external locking profile for engaging a preloaded wellhead connector with matching internal profile. When the connector is locked subsea a metal-to-metal sealing is obtained and a structural conduit is formed. The details of the subsea wellhead profile are specified by the wellhead user and the standarisedH4 hub has a widespread use.\u0000 In terms of well integrity, the wellhead connector is a barrier element during both well construction (drilling) activities and life of field (production). Due to the nature of subsea drilling operations a wellhead connector will be subjected to external loads. Fatigue and plastic collapse are therefore two potential failure modes. These two failure modes are due to the cyclic nature of the loads and the potential for accidental and extreme single loads respectively. Establishing the safe load level that the wellhead connector has structural capacity to handle without failure can be done by deterministic engineering methods. Similarly, a deterministic calculated safe fatigue life is the use limit preventing fatigue failure, assuming no inspections.\u0000 Probabilistic engineering method; Structural Reliability Analysis (SRA), can be applied to a subsea wellhead connector to establish the probability of fatigue failure (PoF). Risk Based Inspection (RBI) is a probabilistic analysis procedure that requires quantified PoF and Consequence of Failure (CoF). The RBI outcome may be used to optimized inspection plans to ensure a safe PoF target level. The RBI methodology is widely accepted, and guidance can be found in several standards.\u0000 Subsea wellheads are normally classified as un-inspectable. During drilling operations commencement, the uppermost section of the wellhead (high pressure housing including H4 hub profile) will be visible and accessible thus allowing for inspection. This uppermost section may also accessible for inspection when a wellhead connector is locked on. From an SRA basis a generic RBI procedure applicable to subsea wellheads are proposed and established for a generic case of a 27” mandrel with a H4 hub. This paper then proceeds to providing the maximum non detectable flaw size performance required for a wellhead inspection tool/method to be efficient. The importance of accidental load and cyclic load magnitude and uncertainty is shown to impact this conclusion. The potential inspectional value of performing BOP connector leak test at regular intervals during the drilling operation has also been investigated and shown to be conditionally limited.\u0000 This paper proposes a procedure for application of RBI to the problem of achieving life extension of a wellhead external locking profile while connected to a wellhead connector. The objective is to propose minimum performance require","PeriodicalId":191387,"journal":{"name":"Volume 2B: Structures, Safety, and Reliability","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129166719","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":"Finite Element Analysis of Structure Strength on Engine Room of a Submerged Waterjet Propelled Ship","authors":"Hanqi Wang, Jiangming Ding","doi":"10.1115/omae2020-19086","DOIUrl":"https://doi.org/10.1115/omae2020-19086","url":null,"abstract":"\u0000 The submerged waterjet offers further benefits with respect to excellent stealth performance, low inflow energy loss, high propulsive efficiency at low and medium speeds, and excellent underwater acoustic performance. It also offers potential for space savings as a result of the high integration with the hull bottom. A parameterized stern line layout method for DTMB 5415 is proposed to design a new ship type fitted with submerged waterjet propeller. Based on the finite element method, the strength analysis and modal analysis of the new hull-form are carried out. The transom equipped with submerged waterjets is constructed by three main parameters which includes tunnel lengths, tunnel transverse positions and shaft angles. CFD calculation of hull flow field and resistance was carried out based on the designed new ship type to evaluate hydrodynamic load. Based on the finite element method, MSC.Patran/Nastran and Abaqus CAE was used to analysis the stress and deformation of the engine room under the static load, and the modal analysis of the engine room was carried out to calculate the vibration frequency and mode of the engine room. Numerical results show that the stress and deformation of the section are agree with the design and the section will not be broken. The different order total modal deformation and natural frequency are given, which lays a foundation for the research of vibration noise prediction and noise reduction technology of ship engine room.","PeriodicalId":191387,"journal":{"name":"Volume 2B: Structures, Safety, and Reliability","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127105534","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":"Cabin Noise Prediction and Acoustic Optimization Design of a Cruise Ship","authors":"Yue Ni, Xiaobin Li","doi":"10.1115/omae2020-18286","DOIUrl":"https://doi.org/10.1115/omae2020-18286","url":null,"abstract":"\u0000 The cabin noise level is an important criterion in high-performance ships, and the noise prediction is the premise of the ship noise control and low noise design. Taking a cruise ship as the research object, a comprehensive application of the statistical energy analysis (SEA) and the finite element-statistical energy analysis hybrid method (FE-SEA) is used to predict the full-frequency noise of typical cabins. The structure-borne noise and air-borne noise, caused by the external excitation from the main engine, propellers and auxiliary machinery, are obtained with the empirical formula. The primary noise sources of typical cabins are analyzed. The noise reduction scheme of sound package is adopted and optimized for the cabin with excessive noise.","PeriodicalId":191387,"journal":{"name":"Volume 2B: Structures, Safety, and Reliability","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121524571","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":"Adjusting Environmental Contours for Specified Expected Number of Unwanted Events","authors":"E. Vanem","doi":"10.1115/omae2020-19293","DOIUrl":"https://doi.org/10.1115/omae2020-19293","url":null,"abstract":"\u0000 Environmental contours are applied in probabilistic structural reliability analysis to identify extreme environmental conditions that may give rise to extreme loads and responses. Typically, they are constructed to correspond to a certain return period and a probability of exceedance with regards to the environmental conditions that can again be related to the probability of failure of a structure. Thus, they describe events with a certain probability of being exceeded one or more times during a certain time period, which can be found from a certain percentile of the underlying distribution. In this paper, various ways of adjusting such environmental contours to account for the expected number of exceedances within a certain time period are discussed. Depending on how such criteria are defined, one may get more lenient or more stringent criteria compared to the classical return period.","PeriodicalId":191387,"journal":{"name":"Volume 2B: Structures, Safety, and Reliability","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131375114","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":"Dynamic Ultimate Strength of a Container Ship Under Sagging Condition","authors":"G. Jagite, H. L. Sourne, P. Cartraud, F. Bigot, Q. Derbanne, Š. Malenica","doi":"10.1115/omae2020-18198","DOIUrl":"https://doi.org/10.1115/omae2020-18198","url":null,"abstract":"\u0000 When technically specifying ships for the future, the following aspects are examples of what we will have even more focus on than today: bigger, lighter, and faster. Thereby, the hydro-elastic type of structural response will be more and more significant. In addition, some of the recent container ships’ designs are with very low values of the “minimum hogging still water bending moment.” Combined with high whipping induced sagging moments, it casts some doubts on the probability of buckling appearance in the upper structure. Therefore, the objective of the research work presented in this paper is to investigate the dynamic ultimate strength of the entire hull girder section, subjected to sagging bending moment associated with wave loads and whipping response. The dynamic ultimate strength is computed and compared with the quasi-static ultimate strength, in order to derive the dynamic load factors, which can be used as an estimator of the dynamic collapse effect.","PeriodicalId":191387,"journal":{"name":"Volume 2B: Structures, Safety, and Reliability","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124718370","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}