The effect of structural discontinuity on antisymmetric response of a container ship

Recent trends in capacity, hence size, growth in container ships have increased the importance of torsion, particularly how it is influenced by the large deck openings and structural discontinuities present in such ships. This paper investigates the consequences of these effects on the ‘dry’ antisymmetric modal characteristics and consequent wave-induced loads. A beam model with more accurate representation of warping and structural discontinuities is applied to a box beam to assess these influences and compare predictions of natural frequencies and mode shapes with previous calculations and finite element (FE) predictions. The analysis is subsequently applied to a feeder containership travelling in regular oblique waves and resultant loads are compared with predictions obtained from previous two (2D) - and three-dimensional (3D) hydroelasticity analyses

Green ship technologies and kite assisted propulsion

Shipping is the key to international trade. Our aim should be to make it more environmentallyfriendly. The proliferation of 'green' legislation and heightened environmental expectationsgenerally have created new market opportunities and seen the emergence of technologicalsolutions that attempt to enhance the green profile of the shipping industry. This presentationwill discuss the opportunities that exist in the area of alternative sources of power and thepotential energy savings by design solutions. Reference will be made to the currenttechnology measures available and define the alternative sources of power that may beuseful for ship design. The second part of the presentation will discuss the current greenshipping technology outlook. Those are divided into technologies that may affect our industryover the short to medium term or over the long term. As a case study a brief analysis of theresults from a theoretical study into kite-assisted propulsion will be discussed

The influence of nonlinearities on the symmetric hydrodynamic response of a 10,000 TEU Container ship

The prediction of wave-induced motions and loads is of great importance for the design of marine structures. Linear potential flow hydrodynamic models are already used in different parts of the ship design development and appraisal process. However, the industry demands for design innovation and the possibilities offered by modern technology imply the need to also understand the modelling assumptions and associated influences of nonlinear hydrodynamic actions on ship response. At first instance, this paper presents the taxonomy of different Fluid Structure Interaction (FSI) methods that may be used for the assessment of ship motions and loads. Consequently, it documents in a practical way the effects of weakly nonlinear hydrodynamics on the symmetric wave-induced responses for a 10,000TEU Container ship. It is shown that the weakly nonlinear FSI models may be useful for the prediction of symmetric wave-induced loads and responses of such ship not only in way of amidships but also at the extremities of the hull. It is concluded that validation of hydrodynamic radiation and diffraction forces and their respective influence on ship response should be especially considered for those cases where the variations of the hull wetted surface in time may be noticeable

Alternative assessment of passenger ship safety - early results from the EU project FLARE

Mitigating flooding risk through passive and active measures is a key step in further increasing the safety of shipping, reducing loss of life and damage to the environment. This paper presents key findings from the EU Horizons 2020 project FLARE (FLooding Accident REsponse) that introduces a novel risk-based methodology beyond the state-of-the-art for “live” flooding risk assessment and control, with potential application to new and existing ships. The project develops a flooding accident model – based on statistics and first-principles tools – that aims to assess the frequencies of flooding events whilst accounting for pertinent environmental conditions and design parameters including ship crashworthiness. Cost-effective risk control options are under evaluation and possible recommendations and/or amendments to the regulatory framework will be submitted to the IMO

Lattice benchmarking of deterministic, Monte Carlo and hybrid Monte Carlo reactor physics codes for the soluble-boron-free SMR cores

Since the use of deterministic transport code WIMS can significantly reduce the computational time compared to the Monte Carlo (MC) code Serpent and hybrid MC code MONK, one of the major objectives of this study is to observe whether deterministic code WIMS can provide accuracy in reactor physics calculations while comparing Serpent and MONK. Therefore, numerical benchmark calculations for a soluble-boron-free (SBF) small modular reactor (SMR) assembly have been performed using the WIMS, Serpent and MONK. Although computationally different in nature, these codes can solve the neutronic transport equations and calculate the required neutronic parameters. A comparison in neutronic parameters between the three codes has been carried out using two types of candidate fuels: 15%235U enriched homogeneously mixed all-UO2 fuel and 18%235U enriched micro-heterogeneous ThO2-UO2 duplex fuel in a 2D fuel assembly model using a 13×13 arrangement. The eigenvalue/reactivity (k∞) and 2D assembly pin power distribution at different burnup states in the assembly depletion are compared using three candidate nuclear data files: ENDF/B- VII, JEF2.2 and JEF3.1. A good agreement in k∞ values was observed among the codes for both the candidate fuels. The differences in k∞ between the codes are ∼200 pcm when cross-sections based on the same nuclear data file are used. A higher difference (up to ∼450 pcm) in the k∞ values is observed among the codes using cross-sections based on different data files. Finally, it can be concluded from this study that the good agreement in the results between the codes found provides enhanced confidence that modeling of SBF, SMR propulsion core systems with micro-heterogeneous duplex fuel can be performed reliably using deterministic neutronics code WIMS, offering the advantage of less expensive computation than that of the MC Serpent and hybrid MC MONK codes

Concepts for a modular nuclear powered containership

With the amendments to the MARPOL Annex VI regulations to control NOx and SOx emissions, fuel prices will increase considerably by 2020. Coupled with depleting fossil fuel reserves and owners’ perceptions on their environmental impact, fossil fuel alternatives are being actively sought. The IMarEST reports that nuclear power is the only emissions free energy which can replace fossil fuels entirely (Jenkins, 2011).Two critical drawbacks for a nuclear powered ship are route restrictions and accidents. The goal of the research underway is to ensure that a concept nuclear containership can sustain an accident without catastrophic consequences as well as operate freely at sea without intervention from port states due to the mode of propulsion.The paper will present the work to date on the concept analysis and how the issue with route restrictions is being addressed by designing a modular vessel consisting of a propulsion module and a cargo module which can decouple outside of territorial waters. A service factor analysis with hydroelasticity models will provide the long term bending moments and the modular coupling concept assessment in open waters for unrestricted service. Accidents will be addressed using risk based design focussing on grounding and collisions in restricted waters using probabilistic model

Luentomuistiinpanoja peruslaivastoarkkitehtuurista

Shipping is responsible for 90% of world trade. The design, equipment and function of ships are subject to constant evolution that intensified recently because of emerging sustainability and safety requirements, the changing patterns of world trade and technological evolution. It is becoming increasingly evident that the Naval Architects and Marine Engineers of the future will be less tied to conventional ship types, will work in less deterministic ways and will have to adapt to market demands. Yet good understanding of the basics shall remain essential. With the above in mind, this set of lecture notes outlines some of the Principles of Naval Architecture and Marine Engineering for use in concept ship design. The material presented can be used by undergraduate students or early stage postgraduate students of Marine Technology.Merenkulku vastaa 90% maailmankaupasta. Laivojen suunnittelu, varustus ja toiminta muuttuvat jatkuvasti, ja ne ovat kiihtyneet viime aikoina nousevien kestävyys- ja turvallisuusvaatimusten, maailmankaupan muuttuvien mallien ja teknologisen kehityksen vuoksi. Tulee yhä ilmeisemmäksi, että tulevaisuuden merivoimien arkkitehdit ja merimoottorit ovat vähemmän sidoksissa perinteisiin laivatyyppeihin, työskentelevät vähemmän deterministisillä tavoilla ja joutuvat sopeutumaan markkinoiden vaatimuksiin. Silti perusasioiden hyvä ymmärtäminen on edelleen välttämätöntä. Edellä oleva mielessä tämä luentosarja sisältää joitakin merivoimien arkkitehtuurin ja meritekniikan periaatteita, joita voidaan käyttää konseptialusten suunnittelussa. Esitettyä materiaalia voivat käyttää perustutkinto -opiskelijat tai meritekniikan jatko -opiskelijat

Hydroelastic modelling for the prediction of wave induced loads on bulk carriers

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN053903 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Elements of Ship Dynamics and Marine Hydromechanics - Lecture Notes

The concept of ship dynamics has a very wide meaning, embracing the fundamentals of both deterministic and performance-based methods. A Naval Architect is expected to have sound appreciation of theoretical concepts of relevance to the prediction and validation of ship seakeeping, dynamic stability, added resistance and manoeuvring in waves. This set of course notes attempts an introduction to the subject along the lines of a synonymous Marine Technology course delivered at Aalto University. The information is presented in ten chapters corresponding to ten lectures and should be considered auxiliary to class tutorials and ship design focused coursework. Special emphasis is attributed on ocean waves, seakeeping, maneuvering and associated principles of marine hydromechanics. The content assumes good knowedge of principles of Naval Architecture, Marine Engineering and is appropriate for last year undergraduate, MSc and DSc students as well as early career professionals. Additional useful information is included in the textbooks:  [1] Hirdaris, S., Mikkola, T.K. (2021). Ship Dynamics for Performance Based Design and Risk Averse Operations, MDPI, Bassel, Switzerland, ISBN: 978-3-0365-0617-3 1.  [2] Hirdaris, S. (2021). Lecture Notes on Basic Naval Architecture, Aalto University publication series SCIENCE + TECHNOLOGY, 6/2021, eISBN: 978-952-64-0486-8  [3] Matusiak, J. (2021). Dynamics of a Rigid Ship - with applications Aalto University publication series on Science and Technology, ISBN: 978-952-64-0399-1 I am grateful to my DSc students Ghalib Taimuri, Mingyang Zhang and Teaching Assistants Zeiad Abdelghafor, Hassan Yosri and Aaron Körkkö for their support during the preparation of this material