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1

Underwater wet repair welding of API 5L X65M pipeline steel

Rogalski G., Fydrych D., Łabanowski J.

Polish Maritime Research

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2017

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S 1

Bibliogr. 27 poz., rys., tab.

EN

This paper presents results of the research of effect of polymer insulation of pipeline made of API 5L X65M steel as well as underwater wet welding parameters on properties of joints made by covered electrodes. Effect of heat input on structure and hardness of joints during repair of underwater pipeline was analyzed. Welding defects like microcracks, micro-lacks of fusion, slag inclusions, as well as HAZ hardness increase over an assumed acceptance criterion for welded joints in pipes without anticorrosion polymer insulation, were identified. A significant effect of polimer insulation on structure and properties of welded joints, was found.

2

Możliwość wykorzystania metodologii FSA do analizy ryzyka przejścia statku nad rurociągiem

Orymowska J., Pilip K.

Autobusy : technika, eksploatacja, systemy transportowe

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2016

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R. 17, nr 12

714--717

PL

Znaczący postęp technologiczny połączony z minimalizacją kosztów i opłacalnością produkcji nowych instalacji przesyłowych, spowodowały w ostatnich latach intensywny rozwój sektora offshore w Polsce, Europie i na świecie. Efektem tego jest duże zagęszczenie podwodnej liniowej infrastruktury przesyłowej (LIP) - rurociągów czy kabli podmorskich. Obszarami szczególnie niebezpiecznymi w zakresie eksploatacji LIP są rejony przybrzeżne, gdzie wzmożona jest intensywność ruchu statków. W celu zminimalizowania ryzyka uszkodzeń sieci, należy już podczas projektowania, a następnie budowy, przeprowadzić szereg analiz dotyczących m.in. aspektów wytrzymałości i doboru materiałów, lokalizacji w aspekcie bezpiecznej nawigacji, wpływu warunków pogodowych oraz intensywności ruchu statków na powierzchni z uwzględnieniem ich ewentualnego wpływu podczas przepływania nad rurociągiem. W artykule skupiono się na ostatnim z wymienionych czynników. Autorzy omówili dostępne metody analizy ryzyka (FSA), wybrali optymalną do przedstawionego problemu, rozpatrzyli możliwe scenariusze zagrożeń i zaproponowali działania niezbędne do uniknięcia bądź zminimalizowania wystąpienia takich przypadków.

EN

Recent technological advance combined with the minimization of costs and a raise in profitability of production of new investments, has in recent years caused an intensive development of the offshore sector in Poland, Europe and all over the world. The result of that, is a big density of underwater transmission pipelines and cables especially in coastal areas where traffic intensity is posing a potential threat to the safety of underwater infrastructure. To avoid or minimize the risk of pipeline damage, a significant number of analyses are needed to be conducted, for example aspects of material strength and its selection, location, impact of the weather conditions and intensity of the vessels movements on the sea surface, taking into account their possible impact when passing over the pipeline. This article focuses on the last of the above mentioned factors. The authors discussed the available methods of risk analysis (FSA), choose the optimal way to solve the problem, considered possible threats scenarios and suggested the necessary moves to avoid or minimize the occurrence of such cases.

3

Application of potential theory in calculating wave-induced vertical forces on horizontal cylinders near a plane boundary

Marcinkowski T., Wilde P.

Archives of Hydro-Engineering and Environmental Mechanics

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2006

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Vol. 53, nr 1

49-69

EN

Hydrodynamic forces acting on a horizontal cylinder located in the vicinity of the bottom are analyzed by a diffraction theory which solves the problem in terms of a velocity potential. The cylinder is assumed to be rigidly anchored to the bottom at a sufficient depth, so that it has no influence on the surface profile. The potential function φ is defined as the sum of the incident wave velocity potential φ w and the scattered wave velocity potential φa. The results of measurements of wave-induced pressures and forces on a horizontal cylinder located close to the bottom are compared with the theoretical solution based on the potential theory for incompressible, perfect fluid and ideal boundary conditions at the bottom and the surface of the cylinder. The experiments were carried out in the Large Wave Channel in Hannover with a cylinder of 0.8 m diameter. Thus the results are in a scale which corresponds to real pipelines. The analysis shows that the potential theory explains the components with double frequency of the wave in pressures and vertical forces as far as the amplitudes are concerned. In the experiments, the Keulegan-Carpenter number is rather low and the inertia hydrodynamic forces on the cylinder are dominant. It seems that the observed phase shift between the force component and the wave results from the energy dissipation which is not considered in the theoretical solution.