Day 3 Thu, September 29, 2022最新文献

{"title":"Medium Voltage Direct Current (MVDC) Fault Detection, Localization, and Isolation","authors":"N. Doerry, J. Amy","doi":"10.5957/smc-2022-073","DOIUrl":"https://doi.org/10.5957/smc-2022-073","url":null,"abstract":"Medium Voltage Direct Current (MVDC) is an attractive power system option for commercial and naval ships. However, the lack of a comprehensive design strategy for MVDC circuit protection is a barrier to implementation. For a range of MVDC architectures, this paper explores the inter-relationships among the different functionalities that isolation devices can have, the technologies for implementing isolation devices, power quality requirements, protective relaying strategies, source design, load design, and energy storage. Because commercial products implementing the technologies do not currently exist for MVDC applications, their costs cannot be determined and therefore the optimal solution cannot yet be determined.","PeriodicalId":404590,"journal":{"name":"Day 3 Thu, September 29, 2022","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123933034","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":"Design Activity Modeling","authors":"N. Doerry, A. Johnson, E. Ammeen, Katherine L. Beaumont","doi":"10.5957/smc-2022-068","DOIUrl":"https://doi.org/10.5957/smc-2022-068","url":null,"abstract":"The design phase of a naval vessel is extraordinarily complex. The numerous interactions between design specialties have great potential to result in misunderstandings and confusion among engineers, which can then lead to deadline extensions or unnecessary rework. To overcome the difficulties coordinating ship design specialties, our effort seeks to simulate candidate design processes through the construction of a complete ship design planning tool. This planning tool lays out the effects of resources, requirements, and product quality on the overall design schedule, allowing ship design managers (SDMs) to more efficiently task and control work. The tool specifically includes the impacts of iterations on the overall convergence of the design. As a demonstration we focused on modeling the power and propulsion elements of the ship design.","PeriodicalId":404590,"journal":{"name":"Day 3 Thu, September 29, 2022","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125303692","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":"Evaluating Feebates for Decarbonization by Required Freight Rate","authors":"J. C. Daidola","doi":"10.5957/smc-2022-016","DOIUrl":"https://doi.org/10.5957/smc-2022-016","url":null,"abstract":"The economics of ship operations are investigated when a feebate system of carbon dioxide equivalent (CO2e) tax levies or subsidies are applied. The CO2e intensity of the ship has been proposed as a means of aiding achieving the IMO goals for reduced shipping emissions. The intended impact on operational costs should spur behavior to reduce emissions, introduce more efficient ships and change to lower carbon fuels. The Required Freight Rate (RFR) was first proposed in the 1960’s as a way to analyze the economic features of a particular ship and its service over its lifetime. It proved to be a means of identifying the optimum vessel characteristics for design and construction, the speed at which it would most economically operate and the required revenue per unit weight of cargo to meet financial goals. The RFR analysis is utilized herein to determine the vessel profitability and fuel consumption at alternate operating speeds along with the impact of a tax levy or subsidy. The result is a rational evaluation of operations with the amount of CO2e and tax or subsidy as variables.","PeriodicalId":404590,"journal":{"name":"Day 3 Thu, September 29, 2022","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126543034","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":"Fatigue Analysis of Swaged Bulkheads","authors":"J. A. Skogberg, Kolby A. Pearson, John Moatsos","doi":"10.5957/smc-2022-087","DOIUrl":"https://doi.org/10.5957/smc-2022-087","url":null,"abstract":"The presented paper describes GD NASSCO research for Fatigue Analysis of Swaged Bulkheads, a Research Announcement project through the National Shipbuilding Research Program (NSRP). The goal is to investigate the fatigue life of structural details on swaged bulkheads compared to those of a structurally equivalent traditionally stiffened bulkhead, through Finite Element Analysis (FEA) supplemented with physical testing. The goal of this project is to demonstrate that swaged bulkheads have equivalent fatigue life or better than a traditionally stiffened bulkhead.","PeriodicalId":404590,"journal":{"name":"Day 3 Thu, September 29, 2022","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129754597","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":"Hydrodynamics of Semi-Submersible Hull Model at Variable Submergences and Froude Numbers","authors":"K. Matveev, L. P. Sung","doi":"10.5957/smc-2022-030","DOIUrl":"https://doi.org/10.5957/smc-2022-030","url":null,"abstract":"Semi-submersible vehicles have low-profile platforms above the water surface while keeping most of their hulls below waterline. In addition to reduced detectability, these craft may potentially have good seaworthiness and hydrodynamic advantage at fast displacement speeds. In this study, exploratory tow tank tests and computational fluid dynamics simulations were carried out with a Suboff model in configurations relevant to semi-submersible vehicles. At different speeds, the optimal drag-lift ratio is found to occur at different submergences, whereas the downward suction force monotonically increases with increasing speed and decreases with increasing draft. The lift center exhibits non-monotonic behavior at variable speeds. Computational simulation results demonstrated good agreement with experimental data and provided insight on contributions of pressure and friction drag components and flow features around hulls. The presented data can be useful for developers of semi-submersible vehicles.","PeriodicalId":404590,"journal":{"name":"Day 3 Thu, September 29, 2022","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126481978","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":"Predicting Ship Power Using Machine Learning Methods","authors":"Anthony Kriezis, T. Sapsis, C. Chryssostomidis","doi":"10.5957/smc-2022-065","DOIUrl":"https://doi.org/10.5957/smc-2022-065","url":null,"abstract":"One of the biggest challenges facing the shipping industry in the coming decades is the reduction of carbon emissions. A promising approach to this end is the use of the growing amount of data collected by vessels to optimize a voyage so as to minimize power consumption. The focus of this paper is on building and testing machine learning models that can accurately predict the shaft power of a vessel under different conditions. The models examined include pure empirical models, pure neural network models, and combinations of the two. Using data on two car carrying vessels for 8 years it was found that neural networks incorporating some physical intuition can achieve a mean absolute percentage error of less than 5%, and an R2 above 95%. This performance can be further improved by the addition of wave information, but it deteriorates when the data collection becomes less frequent.","PeriodicalId":404590,"journal":{"name":"Day 3 Thu, September 29, 2022","volume":"14 10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126085630","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 and Experimental Evaluation of Waterjet Propelled Amphibious Tracked Vehicles","authors":"Taehyung Kim, J. Seo, Y. Heo","doi":"10.5957/smc-2022-066","DOIUrl":"https://doi.org/10.5957/smc-2022-066","url":null,"abstract":"This paper covers the numerical and experimental evaluation including vehicle resistance and self-propulsion performance, waterjet flow rate, and running attitude changes of an amphibious tracked vehicle. A reduced-scale model of the waterjet propelled amphibious tracked vehicle was designed by the Agency for Defense Development (ADD) and was tested in the towing tank. The numerical study was performed over a speed range of 0.3<Froude number (Fn)<0.8 using a second order accurate finite volume method provided by a commercial computational fluid dynamics (CFD) tool to solve the governing Reynolds Averaged Navier-Stokes (RANS) equations. The k-ω model was used for the turbulence closure and the massive separation flow behind the box-shaped-vehicle. The rotation of the impeller was simulated by a moving reference frame method and the running attitude was predicted by a dynamic body fluid interaction method. Good agreement is found for the prediction of the resistance, thrust and torque coefficients of the impeller. The comparisons also made it possible to determine appropriate installation angles of the stern hydrofoil for achievement of lower shaft delivered power and more stable running attitude for high speed amphibious tracked vehicles.","PeriodicalId":404590,"journal":{"name":"Day 3 Thu, September 29, 2022","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131495847","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":"High-Speed Craft Model Design, Data Acquisition and Environment Monitoring for Free-Running Tests","authors":"Xing-shen Wang, O. Sallam, David L. Moulton, Jared Richardson, Rory Sunderland, Benjamin McKeig, Mirjam Furth","doi":"10.5957/smc-2022-085","DOIUrl":"https://doi.org/10.5957/smc-2022-085","url":null,"abstract":"The majority of experimental research conducted on the hydrodynamics of High-Speed Crafts (HSC) has been done in towing tanks. This presents a couple of issues; towing facilities are expensive, and the ideal conditions of the tank create a disparity between experiment and open water performance. Free-running models tested in open water can overcome some of these limitations. This paper presents the detailed design of a free-running model for open water experimental application. The model development includes hull construction, design and integration of a propulsion & steering system, data acquisition system (DAQ) design and testing, as well as environmental monitoring methods.","PeriodicalId":404590,"journal":{"name":"Day 3 Thu, September 29, 2022","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114026301","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":"Multi-Level Structural Design Optimization of Offshore Platform Topsides Deck Truss","authors":"Zhongwei Li, Aimin Wang, O. Dasilva","doi":"10.5957/smc-2022-091","DOIUrl":"https://doi.org/10.5957/smc-2022-091","url":null,"abstract":"Structural optimization was not prioritized in offshore structural design for various reasons. The environmental conditions have many uncertainties. The large-scale offshore structures have complicated systems and shapes. The design process is multidisciplinary. The structural design often only converges towards the end of the project thus very little adjustment will be possible. As a result, the objectives of structural optimization, reducing the cost and enhancing the performance by minimizing structural weight, are often not strong enough to motivate optimization in offshore structures design process. Despite all these factors, there were applications of structural optimization at local level and early design stage where the design space is relatively simple. In recent time, there are growing concerns about the cost and environmental impact of offshore structures. The optimization techniques in computer-aided engineering designs have been proven effective and robust by numerous applications in many industries. Under these circumstances, offshore structures are expected to implement more optimization process in the design. This paper presents a multi-level structural optimization approach in the topsides deck truss design of a floating offshore platform. First, in the concept study phase, fundamental design parameters including the numbers of decks and major truss rows are determined by parametric study. Next, the preliminary design uses topology optimization technique to find optimal material distribution under simplified load conditions and generate basic truss structure configurations. After the initial deck truss structural layout is set up, the individual member sizes are optimized based on Finite Element Analysis and code check results. Last, in the local deck joint detailed analysis, optimal shapes and sizes are selected for local reinforcement structures. The optimized offshore platform topsides deck truss structure demonstrates advantages of lower structural weight, lower manufacturing cost, higher performance, and quantifiable environmental benefits. The practical multi-level structural optimization approach presented in this study utilizes mathematical optimization algorithms, first principle design analysis, and design experiences. The design optimization approach has been effectively applied to the complex offshore platform deck truss system which takes a multi-year project to complete and often requires assumptions and approximated design data at early phase. The optimization approach can be applied to other marine and offshore systems like the floating offshore wind turbine concept development.","PeriodicalId":404590,"journal":{"name":"Day 3 Thu, September 29, 2022","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130059604","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":"Commercial Sustainability - CAPEX Using Probabilistic Simulation Approach","authors":"J. Gullaksen","doi":"10.5957/smc-2022-029","DOIUrl":"https://doi.org/10.5957/smc-2022-029","url":null,"abstract":"In many investment projects, the controlling parameters and events may be uncertain, making the investment project associated with risk. In present context, the investment is defined as acquiring an asset for the purpose of obtaining commercial sustainability, where commercial sustainability aims to achieve the balance between economic, environmental and social impacts through the effective management of resources whilst maximizing organizational profitability. The variability of input parameters will be characterized by stochastic distributions, and the probabilistic simulation can predict the financial model behaviors under uncertainties by an output probability distribution. With sensitivity analysis, the system complexity can be reduced and the cause-and-effect relationship can be explained, for example, which model parameters contribute the most to output variability, which parameters are in-significant and can be eliminated from model and which parameters interact with each other. In a traditional investment analysis method, the effect of sensitivity in input variables, is often based on only one variable considered at a time, whereas a probabilistic simulation approach considers the impact of many variables changing at the same time. The uncertainty is incorporated by specifying inputs as probability distributions and specifying any random events that could affect the project. The simulation process consists of successively generating random numbers, used to select from the probability distribution of each uncertain input parameter. In this paper, a financial evaluation model is developed using a probabilistic simulation approach. The asset investment project discussed, is categorized into asset management and capital expenditure (CAPEX) projects. It accounts for variability, uncertainty and risk, both in the costs and benefits associated with the investment opportunity. Investment planning, approval workflow and management method, is only included as necessary for the context, or applicable. Please note, the financial evaluation method, although it is very important, is only one aspect affecting the investment decisions. In the investment planning and capital budgeting process, it consists of complex aspects in the organizational setting, where it become identified, developed, justified and finally approved.","PeriodicalId":404590,"journal":{"name":"Day 3 Thu, September 29, 2022","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133144955","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}