Autor: He, Liu - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Dynamic characteristics of magnetic coupling in horizontal axis wave energy device
Autorzy:: Zhang, J.
Liu, Y.
Liu, J.
He, T.
Xie, Y.
Powiązania:: https://bibliotekanauki.pl/articles/258488.pdf
Data publikacji:: 2017
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: wave energy
magnetic coupling
dynamic characteristics
transfer function
step response
steady state error
Opis:: To solve the dynamic response problems of magnetic coupling in the horizontal axis wave energy device, this has researched the dynamic characteristicsof magnetic coupling. The fitting formula about torque and angle of the magnetic coupling is obtained through experiments. The mathematical models of the magnetic coupling torque transmission are established. The steady state error of the magnetic coupling and the transfer function of the output angle are obtained. The analytical solution of the step response of the output angle in time domain is derived. The influence of the torsional rigidity, the damping coefficient and the driven rotor’s rotational inertia on dynamic characteristics of the magnetic coupling isanalyzed. According to the analysis results, the design rules of magnetic coupling are proposed.
Źródło:: Polish Maritime Research; 2017, S 3; 165-170
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Research on optimal design of spudcan structures to ease spudcan-footprint interactions in clay and comparative analyses with different measures
Autorzy:: Yu, Huafeng
Sun, Zhenzhou
He, Linlin
Yang, Liu
Powiązania:: https://bibliotekanauki.pl/articles/32890971.pdf
Data publikacji:: 2022
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: spudcan-footprint interaction
novel spudcan shape
VHM curves
stomping
perforation drilling
Opis:: In order to ease consequences of spudcan-footprint interactions during jack-up rigs reinstalling in the vicinity of an existing seabed footprint, three new types of spudcan shapes, that is, a lotus-shaped spudcan with six circular holes, a flat-bottomed spudcan, and a concave-shaped spudcan, were proposed to perform an optimizing study of the spudcan structures, and the effectiveness of them were analyzed comparatively with other different measures. Firstly, 3D Large Deformation Finite Element (LDFE) analyses were carried out using the Coupled Eulerian-Lagrangian (CEL) method in the commercial finite element package ABAQUS. After calibrating the validity of the numerical calculation model against existing centrifuge test data and LDFE results, the differences in interaction mechanism between the novel spudcans and the generic spindle-shaped spudcan were studied when penetrating near an existing footprint with an eccentric distance of 0.5D, and the horizontal range of plastic deformation of the disturbed soils, the inclination angle of the spudcan and the offset distance of the pile legs were analyzed comparatively as well. The results show that the proposed novel spudcans can mitigate the maximum horizontal sliding force and the maximum bending moment at the top of the pile leg obviously, compared with those of the generic one, which were reduced by 32.59%, 22.47%, 28.18%, and 26.32%, 12.88%, 18.02%, respectively. It also can be seen that all novel structures can ease the adverse consequences of spudcan-footprint interactions effectively, and can improve the in -place stability of the spudcan as well. Finally, three possible measures in mitigating interactions of the spudcan-footprint were contrasted, that is, the novel spudcan (represented by the lotus-shaped spudcan with six holes), stomping method, and perforation drilling method. The results show that all of them can reduce adverse impacts induced by interactions of the spudcan-footprint, and also can improve the in-place stability of the spudcan during reinstallation. In addition, among them, according to the effect of reducing the additional stress of the spudcan, the effectiveness of them can be listed as follows: perforation drilling near an existing footprint > the lotus-shaped spudcan with six holes > stomping method. In terms of the vertical bearing capacity of the spudcan, the lotus-shaped spudcan with six holes can improve it as much as 16.33% compared with the spindle-shaped structure due to the particularity of the structure. While reducing the continuity and strength of soil foundations, the perforation drilling measure leads to the decrease of the vertical bearing capacity of the spudcan by 13.07%. It can be concluded that all the three measures have merits and demerits, so the relevant construction environment conditions and engineering practice should be fully considered when selecting measures to deal with interactions of the spudcan-footprint.
Źródło:: Polish Maritime Research; 2022, 1; 43-56
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: A comparative life cycle assessment of marine desox systems
Autorzy:: Cui, Mengqi
Lu, Yingwei
He, Jiahao
Ji, Lei
Wang, Hui
Liu, Shaojun
Powiązania:: https://bibliotekanauki.pl/articles/1573636.pdf
Data publikacji:: 2021
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: life cycle assessment
desulphurization
3E model
Opis:: With new sulphur oxides emission limits carried out in 2020, multiple desulphurisation methods have been proposed. The main desulphurisation scrubber systems were chosen and investigated using life cycle assessment. The whole system life is divided into the construction and operational phases. Three different systems classified by desulphurisers, namely, seawater, NaOH, and Mg-based systems, were modelled in GaBi software. Moreover, environmental, economic and energy aspects (3E model) were introduced for further analysis. Through this study, some conclusions have been drawn. As for the environmental aspect, the seawater system has the most pleasing performance since the primary emissions come from 1.24E+03 kg CO2 and 1.48E+01 kg chloride. The NaOH system causes 1000 times more emissions than the seawater. The Mg-based system has less pollution than the NaOH system, with 5.86E+06kg CO2 and 3.86E+03 kg chloride. The economic aspect is divided into capital expenditure (CapEx) and operational expenditure (OpEx) to estimate disbursement. The seawater system also has the most favourable cost appearance, which takes 1.7 million dollars without extra desulphuriser expenses, based on 10MW engine flue gas treatment. The next is the Mg-based system, which cost 2 million dollars in CapEx and $ 1200/year in OpEx for the desulphuriser. NaOH uses about 2.5 million dollars for construction and $ 30000/year in desulphuriser. As for the energy aspect, the seawater and Mg-based systems use less non-renewable energy than the NaOH system in the construction phase. In conclusion, the seawater system shows the best performance and could be an alternative in SOx control technologies. This study sheds light on the comprehensive evaluation of marine environmental protection technologies for further optimisation.
Źródło:: Polish Maritime Research; 2021, 1; 105-115
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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