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Hydroelasticity analysis of a vessel-shaped fish cage under incident,diffraction and radiation wave fields

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Journal of Ocean Engineering and Science 2023年第4期8卷 418-434页

作者： Yihou Wang Shixiao Fu torgeir Moan Yuwang Xu Tianhu Cheng State Key Laboratory of Ocean Engineering SJTUShanghaiChina Centre for Autonomous Marine Operations and Systems(AMOS) NTNUNorway Faculty of Maritime and Transportation Ningbo UniversityNingboChina

Vessel-shaped fish cages are promising large aquaculture structures developed in recent years,with an overall length of nearly 400 *** this paper,a coupled hydroelasticity model of a vessel-shaped fish cage is used to calculate the motion and structural response in the time ***,the floating body of the cage is discretized into a multimodule system to calculate the frequency-domain hydrodynamic ***,the multimodule system is connected by equivalent elastic beams to consider the hydroelastic be-havior in the time *** hydrodynamic loads of the multimodule system are transformed from the frequency-domain ***,based on the velocity field transfer functions and the motion of the multimodule system,coupling wave fields considering incident,diffraction and radiation waves are built and used to calculate the loads on the net and steel *** iterating the motion response of the multi-module system and the hydrodynamic loads on the net and steel frame in the time domain,the balanced hydroelasticity response of the whole cage is finally *** results show that the hydroelasticity effects have a significant influence on the vertical displacement and cross-sectional load effects of the vessel-shaped fish cage.

关键词： Vessel-shapedfish cage Hydroelasticity Motion response Cross-sectional load effect Net twine tension

Product portfolio map:a visual tool for supporting product variant discovery and structuring

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Advances in Manufacturing 2014年第2期2卷 179-191页

作者： Soren Ulonska torgeir Welo Faculty of Engineering Science and Technology Norwegian University of Science and TechnologyTrondheimNorway Department of Engineering Design and Materials Norwegian University of Science and TechnologyTrondheimNorway

A fundamental criterion for reusing and continuously improving knowledge in product development is ensuring that the knowledge is explicit and *** paper is based on the situation of an engineer-to-order（ETO） manufacturing company,where historically grown product variety and related knowledge are diffuse（tacit）.Consequently,several resources are used in（re）developing derivatives of previous products rather than innovating new *** establish a more competitive configure-to-order（CTO） product strategy,product knowledge needs to be revealed,systemized,and structured,and thus made ***,product-specific knowledge and product variants have been analyzed and subsequently mapped at architectural,functional,and physical levels in one unified map and tested in the form of a proof-of-concept（POC）demonstrator with the introduced SME *** result is a product portfolio map that forms a base for defining a systemized,transparent,unified product variant overview,which can be used as a basis for implementing a cross-variant product architecture and supporting knowledge-based approaches.

关键词： Knowledge-based development(KBD) Knowledge discovery Product architecture Product portfolio mapping

Approaching lean product development using system dynamics:investigating front-load effects

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Advances in Manufacturing 2014年第2期2卷 130-140页

作者： Alemu Moges Belay torgeir Welo Petri Helo Department of Engineering Design and Materials Norwegian University of Science and TechnologyRichard Birkelands Vei 2BN-7491 TrondheimNorway Department of Production Technology University of Vaasa P.O.Box 700FI-65101 VaasaFinland

Competing with successful products has become perplexing with several uncertainties and transmutes from time to time as customers＇ expectations are *** is why manufacturing firms exhaustively strive to look for a better competitive frontier using wellestablished and innovative product development（PD）*** this paper,we would like to answer three research questions：（i）What would be the effects of frontloading in PD？（ii）Can we improve our PD process endlessly？（iii）When is the critical time that the firm should take remedial action for improvements？As a contribution to the vast numbers of improvement methods in new product development（NPD）,this paper investigates the effects of front-loading using set-based concurrent engineering（SBCE）on cost and lead *** are developed and treated using a system dynamics（SD）*** assign a hypothetical upfront investment for SBCE and compare its effects on total cost and lead time of the development *** the research,it is found that the total cost of PD is reduced almost by half-although the front loading is higher in order to encompass multiple design *** total product lead time is reduced by almost 20%.The model reveals the critical time for improvement of the PD *** use SD tool（e.g.,STELLA）for simulation and visualization of the complex PD model,using SBCE as one of several strategies to frontload activities in the NPD process.

关键词： Front-loading Set-based concurrent engineering(SBCE) Innovation Lean product development(LPD) System dynamics(SD)

Comparative numerical and experimental study of two combined wind and wave energy concepts

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Journal of Ocean Engineering and Science 2016年第1期1卷 36-51页

作者： Zhen Gao torgeir Moan Ling Wan Constantine Michailides Centre for Ships and Ocean Structures Norwegian University of Science and TechnologyTrondheimNorway Centre for Autonomous Marine Operations and Systems Norwegian University of Science and TechnologyTrondheimNorway Department of Marine Technology Norwegian University of Science and TechnologyTrondheimNorway

With a successful and rapid development of offshore wind industry and increased research activities on wave energy conversion in recent years,there is an interest in investigating the technological and economic feasibility of combining offshore wind turbines(WTs)with wave energy converters(WECs).In the EU FP7 MARINA Platform project,three floating combined concepts,namely the spar torus combination(STC),the semi-submersible flap combination(SFC)and the oscillating water column(OWC)array with a wind turbine,were selected and studied in detail by numerical and experimental *** paper summarizes the numerical modeling and analysis of the two concepts:STC and SFC,the model tests at a 1:50 scale under simultaneous wave and wind excitation,as well as the comparison between the numerical and experimental *** operational and survival wind and wave conditions were *** numerical analysis was based on a time-domain global model using potential flow theory for hydrodynamics and blade element momentum theory(for SFC)or simplified thrust force model(for STC)for *** techniques for model testing of combined wind and wave concepts were discussed with focus on modeling of wind turbines by disk or redesigned small-scale rotor and modeling of power take-off(PTO)system for wave energy conversion by pneumatic damper or hydraulic rotary *** order to reduce the uncertainty due to scaling,the numerical analysis was performed at model scale and both the numerical and experimental results were then up-scaled to full scale for *** comparison shows that the current numerical model can well predict the responses(motions,PTO forces,power production)of the combined concepts for most of the ***,the linear hydrodynamic model is not adequate for the STC concept in extreme wave conditions with the torus fixed to the spar at the mean water level for which the wave slamming on the torus occurs and this requires further investigati

关键词： Combined wind and wave energy concept Floating wind turbine Wave energy converter Numerical analysis Model test.

Numerical Study of a Novel Procedure for Installing the Tower and Rotor Nacelle Assembly of Offshore Wind Turbines Based on the Inverted Pendulum Principle

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Journal of Marine Science and Application 2017年第3期16卷 243-260页

作者： Wilson Guachamin Acero Zhen Gao torgeir Moan Department of Marine Technology Norwegian University of Science and Technology Trondheim NO-7491 Norway Departamento de Ingenieria Mecanica Escuela Politecnica Nacional Quito 17-01-2 759 Ecuador Centre for Ships and Ocean Structures Norwegian University of Science and Technology Trondheim NO-7491 Norway Centre for Autonomous Marine Operations and Systems Norwegian University of Science and Technology Trondheim NO-7491 Norway

Current installation costs of offshore wind turbines(OWTs) are high and profit margins in the offshore wind energy sector are low, it is thus necessary to develop installation methods that are more efficient and practical. This paper presents a numerical study(based on a global response analysis of marine operations) of a novel procedure for installing the tower and Rotor Nacelle Assemblies(RNAs) on bottom-fixed foundations of OWTs. The installation procedure is based on the inverted pendulum principle. A cargo barge is used to transport the OWT assembly in a horizontal position to the site, and a medium-size Heavy Lift Vessel(HLV) is then employed to lift and up-end the OWT assembly using a special upending frame. The main advantage of this novel procedure is that the need for a huge HLV(in terms of lifting height and capacity) is eliminated. This novel method requires that the cargo barge is in the leeward side of the HLV(which can be positioned with the best heading) during the entire installation. This is to benefit from shielding effects of the HLV on the motions of the cargo barge, so the foundations need to be installed with a specific heading based on wave direction statistics of the site and a typical installation season. Following a systematic approach based on numerical simulations of actual operations, potential critical installation activities, corresponding critical events, and limiting(response) parameters are identified. In addition, operational limits for some of the limiting parameters are established in terms of allowable limits of sea states. Following a preliminary assessment of these operational limits, the duration of the entire operation, the equipment used, and weather-and water depth-sensitivity, this novel procedure is demonstrated to be viable.

关键词：安装方法汽轮机摆钟短舱转子海基学习汇编

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深水定位系统的安全管理(英文)

Journal of Marine Science and Application 2009年第2期8卷 83-92页

作者： torgeir MOAN Centre for Ships and Ocean Structures Norwegian University of Science and Technology

Based on relevant in-service experience, this paper discusses how risks associated with station-keeping systems can be controlled through adequate design criteria, inspection, repair and maintenance practice, as well as quality assurance and control of the engineering processes. Particular focus must be placed on quantitative design for system robustness. The application of structural reliability analysis to quantify safety is briefly reviewed. In particular it was emphasized that reliability predictions based on normal uncertainties and variability yielded lower failure rates than those experienced for predictions of hulls and catenary mooring systems; gross errors in design, fabrication and operation were responsible. For this reason the broad safety management approach mentioned above was proposed. Moreover, it was found that this approach needed to be supported by a quantitative risk assessment. Finally, the challenges in dealing with the effects of human factors in risk management are outlined, along with means to deal with them in a qualitative manner, by the so-called barrier method to limit risk.

关键词：安全管理深海工程控制工程