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On the non-linear analysis of pipeline- soil interaction dynamics on the ocean bed
AuthorsVincent O S Olunloyo ; Charles A Osheku ; O Damisa
Date published2005
AbstractThe non-linear dynamic response interaction of a pipeline on a moving ocean-bed is investigated where the pipeline is idealised as a hollow beam vibrating on a non-linear elastic foundation with a fully developed fluid flowing inside and the assumptions made in respect of the material properties of the soil at the ocean bed are enumerated. Next the effect of the geology is examined by constructing a model for the geomechanical behaviour of the ocean bed. For this purpose the seabed is treated as a rigid porous body. After this the analysis of the results is considered using typical values for some of the soil and physical parameters experienced in practice. Finally results are discussed together with the implication for engineering works associated with the laying of the pipes on the ocean bed.
AuthorsVincent O S Olunloyo ; Charles A Osheku ; O Damisa
Date published2005
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The Impact of Coiled Tubing Fatigue on Pressure and Tension Limits
AuthorsY S Yang
Date published2000
AbstractCoiled Tubing (CT) is subjected to mechanical fatigue damage as it is cycled on and off the reel and over the gooseneck. The impact of fatigue on CT material yield strength and the effects of reduced yield strength on CT pressure and tension limits were evaluated. Experiments on CT fatigue cycling and mechanical tests on cycled CT samples were conducted using both a standard CT fatigue fixture and a tensile testing machine. Based on the test data an empirical relationship between number of fatigue cycles and yield strength reduction was developed. This relationship was incorporated into CT collapse/burst and tension predictive criteria where the reduction in yield strength was not considered previously.
AuthorsY S Yang
Date published2000
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What naval architects should be taught on marine engineering items and how - a view from Finland
AuthorsP Hakkinen
Date published2000
AbstractThe ship machinery topics that are lectured on to naval architecture students show an established content worldwide. There are some variations e.g. turbine propulsion plants receive more attention at US universities than in Europe. Respectively special courses on naval craft and fishing vessels are lectured on in some countries. The paper deals with the changing demands. The key question is ‘What should a naval architect know about ship machinery?’ The paper is based on 10-years of university teaching experience. The feedback of graduated naval architects and their employees is included. Also the students’ views on the courses various teaching methods and textbooks are looked at. Finally some remarks are made on the means of naval architects to maintain and upgrade their professional skills.
AuthorsP Hakkinen
Date published2000
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Laboratory experiments on the hydrodynamics of waves on adverse currents
AuthorsL Cappietti
Date published2003
AbstractA series of laboratory experiments was conducted in a flume to study the effects of adverse currents on regular and irregular waves. The transformation of regular and irregular waves on a sloping bed was studied with and without currents. Effects of the currents on the waves transformations are reported. After some introductory information the experiments are described. Next the results are considered.
AuthorsL Cappietti
Date published2003
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The consequences of environmental requirements on fuel oil specifications and on shipping operational costs
AuthorsP Melissen ; M van Mourik
PublisherIMarE Conferences and Symposia
AbstractThis paper describes the consequences of increased fuel costs on the operational costs of ships. Indicative calculations on shipping transport costs are made with references to the different types of shipping markets affected by increased fuel costs and to what extent these increases could be passed on to the users of shipping services. The impact of environmental legislation is examined regarding desulphurisation of crude oil and the additional of heavy metals to low quality bunkers. Bunker price fluctuations over the last two decades are also examined.
AuthorsDate publishedP Melissen ; M van Mourik
1993
PublisherIMarE Conferences and Symposia
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On the scale effect on thrust deduction
AuthorsG Dyne
Date published1973
AbstractAssessment of scale effects on thrust deduction critically reviewed with reference to - historical background; currently used formulae; components of thrust deduction - displacement friction and wave; and effects of scale.
AuthorsG Dyne
Date published1973
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Endurance and stability of steel structures on the seabed
AuthorsR Haworth ; G T Houlsby ; P M Blair-Fish
Date published1998
AbstractOver time remnants of fixed offshore structures may corrode and split into smaller pieces from the repeated action of waves and currents. Efforts to predict what might happen to the remains of steel structures which may be left on the seabed following decommissioning are described. Of particular concern are remains left in waters deeper than 100 m of the northern North Sea from where complete fixed platforms have yet to be removed. If platform remains are to be left on the seabed the Regulatory Authorities will require evidence that they will remain substantially intact stable and not move across the seabed to become a hazard to fishermen and other sea users. All the factors are presented and considered. It is shown that hydrodynamic loads on debris may be assessed from the effect of waves and currents on the boundary layer close to the seabed. Expressions from lift drag and inertia forces are available from pipeline stability studies. New expressions are derived for stability and resistance of isolated tubulars and prisms on the seabed and compared with the results of model tests on sand and clay. The effect on stability of effective density size shape soil conditions environmental forces and height of fall to the seabed are discussed. It is found that tubulars tend to sink into soft clay but may roll on hard clay. Finally it is pointed out that data from wrecks shows the potential for self-burial due to sediment transport.
AuthorsR Haworth ; G T Houlsby ; P M Blair-Fish
Date published1998
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Numerical study of flow-induced vibration in pipeline on offshore platform
AuthorsDezhong Li ; Ning Mei ; Defu Liu et al.
Date published2002
AbstractThe flow-induced vibration often occurs in the pipelines on offshore platforms when they are used to convey oil in high fluid pressure and there are many undesirable geometric shapes such as too many bends and large variation sections in pipelines on offshore platforms. There are few studies on the vibration of oil-conveying pipelines on offshore platforms. The mechanism of vibration induced by flow in the oil-conveying pipelines on offshore platforms is analysed. Based on the theory of oscillating fluid mechanics mathematical models of unsteady incompressible viscous vibrating flow are established. The expressions for differential coefficients of velocity and pressure in flow are derived according to the parametric polynomial method. The velocity and pressure distributions in flow in the different conditions are obtained. The results show that flow behaviours of flow-induced vibration are affected by pipe structure and properties of fluid. Comparison between numerical result and variational solution shows a good agreement. The method for studying flow-induced vibration in oil-conveying pipeline on offshore platform is shown to be effective.
AuthorsDezhong Li ; Ning Mei ; Defu Liu et al.
Date published2002
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Second report on explosions in very large tankers
AuthorsInternational Chamber of Shipping
Shelf Location227f
AbstractFollowing explosions on three very large tankers in December, 1969, ICS set up a Tanker Safety sub-committee to co-ordinate and evaluate various investigations being conducted on a world-wide basis into the possible causes of these incidents. An interim report was issued on 1st December 1970. The suggestions on tank washing procedures under various tank atmosphere conditions made in the interim report still stand. As shown in the first report, research was initially concentrated on a number of possible sources of ignition in the 1969 explosions. The results of this research can now be said to justify, on a basis of very low probability, the discontinuance, as far as the December 1969 explosions are concerned, of further consideration of the following: impact sparking; compression ignition; auto-ignition by steam heating coils; pyrophoric ignition; R.F. induced current. In research of this nature, which is yet to be finalised, it is inevitable that certain statements are made which might well have to be amended in the light of further confirmatory work. Statements made in this report are therefore subject to this proviso and are based on the best information available at the present time.
AuthorsPublisherInternational Chamber of Shipping
International Chamber of Shipping
Shelf Location227f
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Interim report on ballast water exchange - study on ballast water exchange methods in Japan
AuthorsH Yamamoto
Date published2001
AbstractThis interim report outlines the current movement of the ballast water control in IMO and regional areas in Part 1 and introduces the essential part from the latest study in Japan on ballast water exchange methods in Part 2.
AuthorsH Yamamoto
Date published2001
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International symposium on fire safety of ships Vol 2
AuthorsIMO ; HMMM
Shelf Location223a
AbstractInt Symp held in Piraeus Greece on 9-11 May 1990 Papers are On fire! The need for new thinking Fire protection on large cruiser ships Fire safety on passenger vessels operating in the United States of America
AuthorsPublisherIMO ; HMMM
Hellenic Institute of Marine Technology
Shelf LocationDate published223a
1989
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On the sidewall effects on the non-linear wave loads on a TLP-like structure in a wave tank: analysis of the non-linear near-trapping
AuthorsFabrizio d'Este ; Riccardo Codiglia ; Giorgio Contento
Date published2002
AbstractThe non-linear interaction in diffraction regime of regular waves with a TLP-like structure is studied using the Numerical Wave Tank method. In particular the higher order 'near trapping' phenomenon is analysed with emphasis on the sidewall reflection effects on the harmonic components of the wave elevation and of the forces on the cylinders. From prelimineary results using the Fourier analysis with the sliding window technique it seems that first order in-line terms is only weakly affected by the dimensions of the basin whereas the first order side force on the lateral cylinder shows evident interference effects. At the same time the amplitude of the second order terms of the forces shows a smoother variation with time for the larger basin.
AuthorsFabrizio d'Este ; Riccardo Codiglia ; Giorgio Contento
Date published2002
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Heat transfer on a small Stirling Engine - heat transfer on expansion chamber wall
AuthorsF Toda
Date published1991
AbstractAn experimental Stirling Engine was fitted with heat flux sensors on the expansion chamber and used to study heat transfer between cylinder wall and working gas - heat transfer coefficients are calculated for heating and cooling strokes and the results compared with theoretical predictions.
AuthorsF Toda
Date published1991
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Effects of avoidance of heavy weather on the wave induced load on ships
AuthorsZhi Shu ; Torgeir Moan
Date published2005
AbstractWave-induced hull girder loads such as vertical bending moment amidships are very important for design. The effect of heavy weather avoidance on the long-term wave-induced loads on ships is evaluated. Two hydrodynamic codes VERES based on a 2D strip theory and WASIM based on a 3D Rankine panel method are used to calculate the wave-induced loads and motions on various vessels. Two models for heavy weather avoidance are proposed. The first is based on the assumption that operational criteria relevant to vertical acceleration green water and bottom slamming are fulfilled. The second is based on the assumption that the sea state forecasts are available to the shipmaster and that rerouting is made. Based on the first model considering avoidance of heavy weather and the hydrodynamics results calculated from two codes wave-induced hull girder loads are obtained. The results are discussed - in particular the effect of different hydrodynamic codes and various scatter diagrams. The long-term prediction of wave-induced hull girder loads considering the effect of avoidance of heavy weather will give a relatively more realistic evaluation of the extreme hull girder loads. Finally the results from ship rules are also re-evaluated compared with the long-term prediction with and without heavy weather avoidance.
AuthorsZhi Shu ; Torgeir Moan
Date published2005
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An investigation to erosion and corrosion on steam-feed water-condensation water pipe for marine boiler plant to cope with a disaster caused on a nuclear power plant
AuthorsHiromi Shiihara ; Hisao Matsushita ; Yuzhong Song et al.
Date published2005
AbstractSevere damage was caused to a Japanese nuclear power plant in August 2004. This was caused by failure on a condensation water pipe in a secondary line. A similar type of failure could occur on a steam-feed water-condensation water pipe for a main or auxiliary boiler plant in ships. Subsequently the occurrence mechanism and circumstances of such a failure on the piping system of ships was investigated. The results confirmed that the same fault could occur in such ships. This failure called FAC (flow accelerated corrosion) is caused by erosion-corrosion at a place where the flow is turbulent such as a behind an orifice or control valve or at a bending such as an elbow which is strongly influenced by temperature flow velocity and the pH of the fluid. Wall pipe thickness is measured in such locations and under such conditions using an ultra-sonic testing machine.
AuthorsHiromi Shiihara ; Hisao Matsushita ; Yuzhong Song et al.
Date published2005
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A systematic study on the effect of main design parameters and internal layout on damage stability characteristics of ro-ro vessels
AuthorsC G Politis ; F del Castilio
Date published2003
AbstractA large number of design parameters are known to affect damage stability of ro-ro passenger ships. Amongst these and of great importance are the number and location of transverse bulkheads the location of longitudinal bulkheads below the main deck the length of lower hold the location of main deck and double bottom the existence of central or side casings above main deck etc. The aim here is to estimate the influence of these parameters on the attained subdivision index A of the vessel. To accomplish this a representative group of ro-ro and ro-pax vessels is selected and starting from the original designs the parameters mentioned above are systematically varied and damage stability calculations are carried out for the new models. The results obtained on the attained subdivision index A are presented and critically reviewed and suggestions for improved design are derived.
AuthorsC G Politis ; F del Castilio
Date published2003
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Effect of shielding gas composition on the properties of hyperbaric GMA welds in Duplex steels
AuthorsN Ware ; J F dos Santos ; I Richardson
Date published1994
AbstractAn attempt is made to carry out a preliminary examination on the effects of selected shielding gas compositions on the weld metal chemical composition and microstructural balance of welds in duplex stainless steel for working depths down to 300msw. Bead-on-plate welds are conducted on duplex stainless steels with a variety of shielding gas mixtures at pressures of 11bar 21bar and 31bar. Weld metal absorption of active gases and the subsequent effect on resultant chemical composition and phase balance are assessed. The experimental procedure materials and equipment are looked at. The results are discussed.
AuthorsN Ware ; J F dos Santos ; I Richardson
Date published1994
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Effects of geometric imperfections on the strength of composite panels in ship hulls
AuthorsK Misirlis ; J Downes ; R S Dow
Date published2009
AbstractA numerical investigation on the effects from initial imperfection shapes on the strength of long fibre-reinforced composite panels is presented in this paper. Fourteen alternative initial geometric imperfections are imposed in long plates for two alternative lay-up configurations; a tri-axial and a balanced woven roving configuration. The sectional response is investigated with nonlinear finite element analysis which incorporates a progressive failure model for the degradation of the material properties. For the analysis both thick and thin panels are considered with breadth to thickness ratios of 10 and 50 respectively. The comparison focuses on the effects on stiffness and ultimate strength of the panels and uses as a basis the preferred buckling mode imperfection for each lay-up configuration. Results demonstrate a conservative approach when adopting the preferred buckling mode shape for overall initial imperfections and a significant reduction on performance from localised imperfections.
AuthorsK Misirlis ; J Downes ; R S Dow
Date published2009
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Full-scale trials in varying depths of water on a King Class fast patrol vessel
AuthorsC Thew
Date published1988
AbstractA paper describing the full-scale trials carried out on a Royal Hong Kong Police `King Class' 26m semi-planning fast patrol boat at various depth/draft ratios between 2.96 and deep water over a range of Froude numbers between 0.3 and 0.8. Results are also given in one location for the effect on performance of varying displacement and for both inward and outward turning propellers. Reference is made to previous comprehensive trials carried out at the turn of the century on the HDMS Makrelen Sobjornen S.119 and HMS Cossack. Data are presented to enable preliminary powering calculations based on published information and that given in this paper. Finally comments are made on the present model tank and theoretical procedures for power predictions for this type of craft.
AuthorsC Thew
Date published1988
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Full-scale Trials on a Small High Speed Naval Craft With Focus on Slamming
AuthorsA Rosen ; O Rutgersson
Date published1998
AbstractAs a part of a co-operation project between the Division of Naval Architecture at KTH Stockholm and the Swedish Defence Material Administration full-scale trials have been performed on a small naval craft in rough seas. This paper is the first presentation of these trials. Characteristics of impacts puls lengths and rise times are discussed. Comparison is made between statistical distributions of peak values and therefrom derived Rayleigh distributions. A brief study is made on filtering of acceleration recordings. The results are used to verify computer simulations indicating that bow seas would give higher pressure magnitudes than head seas. Practical problems related to this kind of full-scale tests are discussed for example operational considerations when determining extreme levels for design criteria. Areas of further studies are exemplified e.g. simulations and correlations between pressure accelerations and structural response.
AuthorsA Rosen ; O Rutgersson
Date published1998