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64 Scientific Journals of the Maritime University of Szczecin, no. 64 / 2020



 

Recent Submissions

  • Kostecka, Ewelina (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    This article presents joining methods (welding and sealing) of single-polymer composite materials in a hot air stream. The research material was created using the film-stacking method, which involves pressing successive fractions of polyethylene terephthalate-modified with glycol (PET-G) at defined technological conditions, such as pressure, temperature, and time. Joining method analysis was carried out based on the tensile test results. Analysis of the obtained results showed that the properties of the overlapped weld joint were the best because they were closest to the original materials. In contrast, PET-G welded joint properties were the worst because the PET-G welded joint does not contain fibers, which enhanced the weld; therefore, the fastest breakage of the material was observed at the welding location. For the overlapped weld, the weld itself is more resistant because the joint surface is influenced by friction forces between joined materials.
  • Pacana, Jacek; Homik, Wojciech (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    This study was designed to determine the vibroactivity parameters of a hermetic harmonic drive. A specially-prepared test bench was used to measure the normal velocity of vibrations and acoustic pressure generated by the unit. Piezoelectric sensors were applied to measure the characteristic values on the body of the prototype. In selected sections of drive, we determined the effective values of acceleration ae and frequency f. For the same points, the effective values of vibration velocity Vc were determined for the corresponding frequencies. The findings presented in this paper enable the assessment of a toothed gear in terms of the quality of its workmanship and wear-related deterioration, which are very important due to the characteristic work of this special drive
  • Gostomski, Eugeniusz; Nowosielski, Tomasz (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    The aim of the article is a synthetic presentation of the complex process of financing investments related to shipbuilding and purchase. The first part presents the concept of shipbuilding cycles and the relationship between the shipbuilding industry and the shipping market. The paper then reviews the concepts and literature related to the shipbuilding industry, shipbuilding financing, and ship purchase. Lastly, the current state of the shipbuilding market is described. The results of the analysis indicates possibilities of financing the purchase of new vessels including mortgage bonds.
  • Szelangiewicz, Tadeusz; Żelazny, Katarzyna (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    Unmanned, remotely or autonomously ships are the fastest growing new technology in maritime transport in recent years. The design of unmanned vessels envisions clean, emission-free electric propulsion. The costs of building physical models and target vessels are high, but the expected benefits are generating increasing interest in such vessels. This article presents the current state of research in the field of unmanned ships and the technical, legal and administrative problems that need to be solved in order for these ships to be used by the general public.
  • Graylee, Adeleh; Yousefifard, Mahdi (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    This paper presents a numerical investigation of the hydrodynamic performance of a modified sandglass-type FPSO (Floating Production, Storage and Offloading) with different geometrical parameters. The influence of the roll damping plate on heave and pitch motions of the FPSO was studied in regular waves. To estimate the hydrodynamic performance and utilize the results on the design stage of the FPSO, the boundary element method (BEM) was used. Furthermore, the hydrodynamic performance of two cylindrical and sandglass-type FPSOs under the same conditions was compared in different waves. Five sandglass-type FPSOs with dissimilar inclination angles were utilized with the constant draft. The effects of different inclination angles, including various radii of water-plane part of the floating object on hydrodynamic responses and wave forces applied to the FPSO, were investigated, and presented here. Numerical results were compared against published experimental data of a sandglass-type model, and good agreement was achieved. Based on the simulation results, a conclusion that a sandglass-type FPSO with the inclination angle of 35 degrees proposes proper hydrodynamic performance in both heave and pitch motions for all ranges of wave frequencies was reached. In addition, as it was predicted, the effect of heading sea on a sandglass-type FPSO was significant compared to other wave directions. Finally, by adding a damper plate to the floor of the platform, its hydrodynamic performance is improved. For numerical analysis of the modified FPSO, three different damper sizes are used to investigate its effect on the reduction of the pitch motion amplitude in waves.

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