Wyniki wyszukiwania - BazTech

1

Study on hydrodynamic configuration parameters of vertical-axis tidal turbine

Li Guangnian, Chen Qingren, Liu Yue, Zhu Shanqiang, Yu Qun

Polish Maritime Research

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2020

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nr 1

116--125

EN

In this paper, a numerical code for predicting the hydrodynamic performance of vertical-axis tidal turbine array is developed. The effect of the tip speed ratio, solidity, and preset angle on the hydrodynamic performance are discussed using a series of calculations. The load principle of the rotor and the variation principle of the turbine power coefficient are studied. All these results can be considered as a reference for the design of vertical-axis tidal turbines.

2

Evaluation of ship structure reliability during design, maintenance, and repair phases

Kerdabadi M. S., Sakaki A., Izadi A.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2018

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nr 53 (125)

19--27

EN

In the present study, the reliability evaluation application during design, maintenance and repair phases have been investigated for the girder of a ship’s hull. The objective of the project was to develop reliability-based methods which are to be used for the design of ship structures, in particular by the calibration of the safety factors in the design rules. In order to evaluate the structural strength, the extended model of the ultimate limit state of the hull-girder, regarding corrosion and fatigue defects, has been used based using a time-dependent probabilistic analysis. Time-dependent reliability has been evaluated using the required minimum elastic section modulus; in the case of fatigue in a ship’s deck this process has been done using mechanical fracture and the S-N curve. The results from the reliability evaluation using the Monte-Carlo simulation method and First-order reliability methods (FORM), indicated that these two methods agreed well. Analysis of the corrosion defect reliability showed a decrease of the structure’s reliability during its lifetime; hence it is possible to use the reliability criteria in the design phase in order to achieve a better perception of the structure’s operation during its lifetime with regard to environmental conditions. A comparison between the fatigue analysis results showed that the fracture mechanics method gave more conservative results compared to the S-N curve method, because of the way it considers early crack size.

3

Ocena wytrzymałości konstrukcji zawierającej pęknięcia

Jasztal M.

Mechanik

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2016

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R. 89, nr 7

708--709

PL

Artykuł przedstawia zagadnienia oceny wytrzymałości elementów konstrukcji zawierających pęknięcia. Dokonano porównania nośności elementu z pęknięciem, wyznaczonej klasyczną metodą naprężeń nominalnych oraz metodą opartą na mechanice pękania. Pokazano, jak sposób obciążenia oraz położenie pęknięcia wpływają na wartość naprężeń wokół wierzchołka pęknięcia. Zamieszczono przykład obliczeń numerycznych współczynnika intensywności naprężeń z wykorzystaniem oprogramowania ANSYS.

EN

Presented paper includes strength evaluation of cracked structure. Author draw a comparison between structure element’s effort with use of classic nominal stress method and fracture mechanics method. The example illustrates influence of load mode and crack location on stress value around crack tip. Example of numerical calculation of stress intensity factor with use of ANSYS software wasattached.