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Wyszukujesz frazę "ship's roll" wg kryterium: Temat


Tytuł:
Application of statistical methods and artificial neural networks for approximating ships roll in beam waves
Autorzy:
Cepowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/259233.pdf
Data publikacji:
2005
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship's roll
irregular wave
approximation
neural networks
regression methods
Opis:
In the paper, were presented approximations of numerical calculations of ship's roll on the basis of main service parameters of the ship. This way were obtained several relationships which make it possible to approximate ship roll in regular and irregular waves by using the parameters available in the phase of voyage routing. The relationships were elaborated by means of artificial neural networks as well as linear and non-linear regression methods. A comparative analysis of the methods regarding approximation accuracy against standard data was also performed.
Źródło:
Polish Maritime Research; 2005, 2; 22-28
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of 2nd generation stability code for 7600DWT bulk carrier with high value of GM, being in dead ship condition in irregular waves
Autorzy:
Kacprzak, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/29521075.pdf
Data publikacji:
2023
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
ship's roll
weather criteria
stability assessment
2nd generation stability criteria
strip theory
bulk carrier
Opis:
The main issue of this article is to apply and investigate the application of second stability criteria for bulk carriers in typical loading conditions sailing in irregular waves. The author, by the use of linear strip theory, calculates the significant amplitudes of the ship roll with respect to wave height, incident wave angles, and mean sea period. A basic stability analysis, in this case, could be insufficient when considering other related factors like cargo shift, taking up water on the weather deck, wind gusts, inaccuracy of transverse metacentric height, and the case of changing transverse metacentric height in long-crested waves. This article shows that, in some waving conditions, the weather criteria based on standard assumptions of the ISC 2008 may be insufficient. The application of the author’s method of safety margin may increase vessel safety in view of weather criteria.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2023, 75 (147); 14-19
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method for ship’s rolling period prediction with regard to non-linearity of GZ curve
Autorzy:
Wawrzyński, W.
Krata, P.
Powiązania:
https://bibliotekanauki.pl/articles/281346.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
ship natural roll period
GZ approximation
rolling prediction
safety against capsizing
Opis:
The paper deals with the problem of prediction of the rolling period. A special emphasis is put on the practical application of the new method for rolling period prediction with regard to non-linearity of the GZ curve. The one degree-of-freedom rolling equation is applied with using the non-linear stiffness moment and linear damping moment formulas. A number of ships are considered to research the discrepancies between the pending GM-based IMO- -recommended method and the results of conducted numerical simulations performed for a wide range of operational loading conditions. Since the research shows some drawbacks of the IMO formula for the ship rolling period, a new formula is worked out and proposed instead.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 4; 1329-1343
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Susceptibility of the roll equation to the bifurcation phenomenon depending on the damping coefficient value and form of the roll damping formula
Autorzy:
Wawrzyński, W.
Powiązania:
https://bibliotekanauki.pl/articles/135685.pdf
Data publikacji:
2017
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
ship stability
ship rolling
bifurcations
roll resonance
roll damping coefficient
formulas
Opis:
This paper deals with the susceptibility of the roll equation to the bifurcation phenomenon depending on the damping coefficient value and form of the roll damping formula. Generally, the bifurcation phenomenon depends mainly on the shape of the righting arm curve (GZ curve), but roll damping also has a significant impact. The commonly used formulas for roll damping are presented, as well as values of the linear equivalent roll damping coefficient, calculated according to the simple Ikeda method. Values of the linear equivalent roll damping coefficient were calculated for a wide spectrum of roll amplitudes and roll frequencies for two ships. The loading conditions for these ships were selected to show different GZ curve characteristics. One ship has a softening spring characteristic and the second has a hardening spring characteristic. For these two ships, a number of calculations of roll spectra are presented where the bifurcation phenomenon occurs. Calculations were made for different damping coefficient values and forms of the roll damping formula.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2017, 52 (124); 161-169
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of optimum hull form for passenger car ferry with regard to its sea-keeping qualities and additional resistance in waves
Autorzy:
Cepowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/258898.pdf
Data publikacji:
2008
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
sea-keeping qualities
roll-on/roll-off ferry ship
rolling
transverse accelerations
vertical accelerations
motion sickness index
additional resistance in waves
ship hull form
ship design parameters
artificial neural networks
fuzzy logic
Opis:
This paper presents a method which makes it possible to determine optimum hull form of passenger car ferry with regard to selected sea-keeping qualities and additional resistance in waves. In the first phase of investigations a hull form characterized by the highest qualities was selected from the list of similar ships. Next, its optimum dimension ratios were determined. Design criteria were formulated by using a method based on deterministic scenarios, but objective functions of partial targets were determined in the form of artificial neural networks. To select the best design variants elements of fuzzy logic were used, that made it possible a.o. to show merits of the design by means of linguistic variables. Such approach made it possible to find the best hull form and its dimensions from the point of view of all considered criteria simultaneously.
Źródło:
Polish Maritime Research; 2008, 2; 3-11
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of the natural frequency of ship’s roll with regard to various models of roll damping
Autorzy:
Krata, P.
Wawrzyński, W.
Powiązania:
https://bibliotekanauki.pl/articles/244403.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
sea transport
ship stability
ship rolling
roll damping coefficient
Opis:
One of the most important dynamic phenomenon recognized as dangerous to seagoing ships is the resonance gain of rolling. This may occur due to nonlinearity of ship response in resonance conditions, i.e. when the encounter wave frequency is similar to the natural frequency of ship roll motion. Such coincidence should be avoided therefore shipmaster steers clear of some configurations of speed and course resulting in potential synchronous rolling. Nowadays, according to the IMO Intact Stability Code the natural period of roll is determined with the use of very simplified GM-based formula. The paper deals with the problem of more sophisticated prediction of ship’s natural rolling frequency with the use of the one degree-of-freedom roll equation with regard to nonlinear restoring moment. A special emphasis is put on the damping coefficient modelling which remains one of the crucial issues in terms of rolling simulation. Two typical approaches to the damping coefficient estimation are tested, the linear and the nonlinear one according to Ikead’s method. The set of ship roll simulations is carried out for a wide range of excitation frequency and a variety of exciting moment. The results of computation focused on the natural frequency of ship roll prediction are compared to assess the influence of damping model selection.
Źródło:
Journal of KONES; 2016, 23, 3; 289-296
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of ship motions in irregular waves based on response amplitude operators evaluated experimentally in noise waves
Autorzy:
Bielicki, Sebastian
Powiązania:
https://bibliotekanauki.pl/articles/1573664.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
seakeeping
roll motions
noise
ship motions
experiments
Opis:
The most common methods for predicting ship roll motions in a specified sea state are direct measurements of motions in a representative irregular wave realisation (time domain) or calculations of motions from response amplitude operators (RAOs) in the frequency domain. The result of the first method is valid only for the tested sea state, whilst the second method is more flexible but less accurate. RAO-based predictions are calculated assuming a linear model of ship motions in waves. RAO functions are usually evaluated by means of tests in regular waves for a limited number of frequencies and a constant wave amplitude. This approach is time-consuming and the discrete form of the RAO functions obtained for a limited number of frequencies may lead to discrepancies in the prediction of seakeeping and often does not allow the actual amplitude of the response in resonant frequency to be determined. Another challenge is the appropriate selection of wave amplitude for tests due to the considerable influence of viscous damping on roll response in irregular sea waves. There are alternative methods for the experimental determination of RAO functions and one of them is presented in this study. The presented approach allows RAO functions to be evaluated in one run by the generation of irregular waves characterised by a white or coloured noise spectrum. This method reduces the experiment duration, with almost continuous RAO characteristics obtained. The flat (white noise) and linear (coloured noise) wave spectral energy characteristics are considered in the experiment and the obtained predictions are compared with the results of accurate measurements in irregular waves.
Źródło:
Polish Maritime Research; 2021, 1; 16-27
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Virtual ship’s roll decay test with the use of CFD technique
Autorzy:
Krata, P.
Jachowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/243570.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
sea transport
ship stability
roll simulation
roll decay test
computational fluid dynamics
Opis:
Since safety of navigation is related to the stability performance of a ship, the transverse stability is routinely calculated and measured. One of the crucial experimental approach is a roll decay test. Although, an obtained result of the roll decay test carried out on the full-scale ship needs to be compared to a benchmark enabling an estimation of the relevant stability. Nowadays such a benchmark is just based on the simplified GM-based IMO-recommended formula. This research aims at the more sophisticated method of ship’s natural period of roll estimation and thus her stability assessment. The CFD (computational fluid dynamics) technique is applied and the result of the free roll simulation is compared to the solution of a roll equation. The one degree-of-freedom roll equation is applied with regard to the nonlinear ship righting moment and the nonlinear damping moment obtained according to Ikeda’s method. The six degrees-of-freedom simulation of ship’s roll decay test was carried out by the use of FlowVision code utilizing the Reynolds-averaged Navier–Stokes equation with regard to the turbulent flows based on the eddy viscosity concept. The semi-empirical k-ε turbulence model was applied. Thereby, the CFD-based approach allows to get rid of any assumptions regarding the value of the damping coefficient, which is an advantage over the roll equation based approach.
Źródło:
Journal of KONES; 2016, 23, 2; 215-221
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analysis of shear forces, bending moments and roll motion during a nodule loading simulation for a ship at sea in the Clarion–Clipperton Zone
Autorzy:
Kacprzak, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/1818885.pdf
Data publikacji:
2021
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
nodule loading
ship
shear force
bending moment
wave
roll
Opis:
This article presents an analysis of internal forces and roll motion during a nodule loading simulation for a ship at sea. The study carried out a full assessment of ship behavior during loading, which took into account wave height and period occurrence around the Clarion–Clipperton Zone by the use of an operational efficiency index. One of the aims was to verify whether waves have an influence on excessive ship motion and internal forces during nodule loading. Two alternative loading sequences were developed and compared by taking loading time, shear forces, bending moments, roll motion and waving into account. The research shows that loading is only possible during specific sea weather conditions for the selected bulk carrier.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2021, 65 (137); 9-20
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Procedura obliczeń dla zjawiska rezonansu parametrycznego kołysań bocznych statku w kryteriach statecznościowych drugiej generacji
Procedure of calculation the ship parametric rolling in the second generation stability criteria
Autorzy:
Chorab, P.
Powiązania:
https://bibliotekanauki.pl/articles/311926.pdf
Data publikacji:
2016
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
rezonans parametryczny
kołysania statku
bezpieczeństwo statku
parametric roll resonance
ship rolling
safety of the ship
Opis:
W artykule omówiona została procedura obliczeń dla wystąpienia zjawiska rezonansu parametrycznego kołysań bocznych w kryteriach statecznościowych drugiej generacji. Zjawisko rezonansu parametrycznego kołysań bocznych statku jest zjawiskiem znacząco wpływającym na poziom bezpieczeństwa statecznościowego, przy wystąpieniu szczególnych parametrów ruch statku i falowania morskiego. Ze względu na trwające prace na kryteriami statecznościowymi drugiej generacji, zjawisko to zostało uwzględnione w projekcie nowych kryteriów jako jeden z tak zwanych defektów statecznościowych. W pracy przedstawiono kolejne etapy obliczeń na poziomie pierwszym i drugim procedury celem określenia podatności statku na wystąpienia badanego defektu statecznościowego. Omówiono kolejność obliczeń, zakres potrzebnych danych wejściowych oraz interpretację otrzymanych wyników.
The article discussed the procedure for the calculation of parametric rolling failure mode in the second generation criteria. The phenomenon of parametric rolling of the ship is significantly affects the level of ship stability safety, occurrence in specific parameters of ship movement and sea waves. Due to the present work on second generation stability criteria, phenomenon it has been included in the draft new criteria as one of the so-called failure mode. The paper presents the stages of the calculation in the first and second levels in order to determine the vulnerability of a ship on this failure mode. Discussed the order of evaluation, the scope of the necessary input data and interpretation of results.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2016, 17, 12; 79-84
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Second Generation Intact Stability Criteria: on the validation of codes for direct stability assessment in the framework of an example application
Autorzy:
Bulian, G.
Francescutto, A.
Powiązania:
https://bibliotekanauki.pl/articles/260465.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
large amplitude ship motions
second generation intact stability criteria
nonlinear roll
sub-harmonic resonance
validation
Opis:
The Sub-Committee on Stability and Load Lines and on Fishing Vessels Safety (SLF) of the International Maritime Organization (IMO) has undertaken the development of so-called “Second Generation Intact Stability Criteria” (SGISC) with the intention of providing a new set of rules covering those phenomena which are not properly covered by present, mostly semi-empirical, requirements. The first two levels of the envisioned 3+1 tiers structure of SGISC are so-called “vulnerability assessment” levels: most of the discussion has so far been dedicated to these levels. At the highest level there is the so-called “Direct Stability Assessment”, which is also strictly linked with the development of ship-specific “Operational Guidance”. Recent discussion on the topic of “Direct Stability Assessment” (DSA) has touched the issue of “validation” of numerical codes to be employed at this level. Stimulated by, and in view of, the ongoing IMO discussion, this paper presents the results of a recent series of experiments in beam waves (mono-/bichromatic, irregular) and associated simulations based on a 6-DOF blended code. Nonlinear harmonic and sub-harmonic resonances are observed and simulated.
Źródło:
Polish Maritime Research; 2013, 4; 52-61
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Predykcja składowej tłumienia kołysań bocznych statku dla stępek przechyłowych. Porównanie skróconej i pełnej metody Ikedy
Bilge Keel Damping Component Prediction. Comparison of the Simple and Full Ikeda;s Method
Autorzy:
Wawrzyński, W.
Powiązania:
https://bibliotekanauki.pl/articles/341884.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Morski w Gdyni. Wydawnictwo Uniwersytetu Morskiego w Gdyni
Tematy:
kołysania boczne statku
stępki przechyłowe
tłumienie kołysań bocznych statku
ship rolling
bilge keel
roll damping
Opis:
Artykuł prezentuje porównanie wartości współczynnika tłumienia kołysań bocznych statku dla stępek przechyłowych, wyznaczonego przy zastosowaniu pełnej metody Ikedy oraz jej uproszczonej wersji. W materiale omówiono obie procedury wyznaczania wartości współczynnika tłumienia kołysań bocznych dla stępek oraz zaprezentowano wyniki obliczeń tego współczynnika dla drobnicowca. Przedstawiono również dla dwóch statków znacząco różniących się wielkością porównanie charakterystyk zmian współczynnika tłumienia dla stępek, w zależności od relacji szerokości stępek do ich długości, przy zachowaniu stałej wartości całkowitej powierzchni stępek. Wykonane obliczenia pokazują, że uproszczona metoda Ikedy, pomimo że opracowana została przy zastosowaniu metody regresji, z wykorzystaniem serii wyników uzyskanych metodą pełną, daje zbliżone wyniki obliczeń tylko dla małych amplitud kołysania statku i niewielkich wartości całkowitej powierzchni stępek przechyłowych.
This paper presents a comparison of the bilge keel component of roll damping, determined by the full Ikeda’s method and its simplified version. The material discusses both procedures for determining the value of the bilge keel component and the calculation results for this component for the general cargo ship are presented. A comparison of the characteristics of value changes of bilge keel damping coefficients in dependence on the relationship of the bilge keel width to its length, while keeping the bilge keel area constant, is presented for two ships with significantly different particulars. Despite the fact that the simplified Ikeda’s method was developed using the regression method for series results obtained by the full method, the calculations made present that the simplified method give comparable results only for small roll amplitudes and small bilge keels areas.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Gdyni; 2017, 102; 124-141
1644-1818
2451-2486
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Gdyni
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badanie kołysań bocznych statku na założonej trasie żeglugi
Research of Ships Roll on a Selected Route
Autorzy:
Cepowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/906648.pdf
Data publikacji:
2004
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
właściwości morskie
kołysania boczne
kryteria operacyjno-ograniczające
trasa żeglugi
seakeeping properties
roll
seakeeping criteria
ship's route
Opis:
W artykule zaproponowano metodę umożliwiającą wybór trasy żeglugi statku ze względu na kołysania boczne. Jako kryterium wykorzystano kryterium operacyjno-ograniczające dla kołysań bocznych. Na podstawie proponowanej metody przeanalizowano wybrane warianty trasy żeglugi statku i wybrano wariant najkorzystniejszy.
The paper presents a method of ship's route selection due to roll prediction. The seakeeping - operability value of roll was applied as criterion. The selected variants of the ship's route have been analyzed on the basis of proposal method and the best variant has been selected.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2004, 3 (75); 31-39
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the modeling of car passenger ferryship design parameters with respect to selected sea-keeping qualities and additional resistance in waves
Autorzy:
Cepowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/258828.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
sea-keeping qualities
roll-on/roll-off ferryship
rolling
motion sickness index
lateral accelerations
additional resistance in waves
ship design parameters
modeling
artificial neural networks
optimization
Pareto method
Opis:
This paper presents the modeling of car passenger ferryship design parameters with respect to such design criteria as selected sea-keeping qualities and additional resistance in waves. In the first part of the investigations approximations of selected statistical parameters of design criteria of ferryship were elaborated with respect to ship design parameters. The approximation functions were obtained with the use of artificial neural networks. In the second part of the investigations design solutions were searched for by applying the singleand multi-criterial optimization methods. The multi-criterial optimization was performed by using Pareto method. Such approach made it possible to present solutions in such form as to allow decision makers (shipowner, designer) to select solutions the most favourable in each individual case.
Źródło:
Polish Maritime Research; 2009, 3; 3-10
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prognozowanie kołysań bocznych statku za pomocą sztucznych sieci neuronowych
Application of Artificial Neural Networks to Prediction of Ship Rolling
Autorzy:
Staszewska, K.
Cepowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/359916.pdf
Data publikacji:
2004
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
właściwości morskie
efektywność operacyjna
kołysania boczne
kryteria stateczności
kryteria operacyjno-ograniczające
EXPLO-SHIP 2004
seakeeping properties
seakeeping operability
roll
stability criteria
seakeeping criteria
Opis:
Przedstawiono metodykę aproksymacji odpowiedzi statku na falowanie morza opartą na parametrach eksploatacyjnych statku. Powyższa metodyka umożliwia wykorzystanie danych zarejestrowanych na statku. W celu przetestowania metody, rzeczywiste kołysania statku symulowano wartościami obliczonymi numerycznie za pomocą metod dokładnych.
The paper presents a methodology of approximation of ship's response to wave action impact. The methodology, based on recorded ship's operational parameters, makes it possible to modify approximated functions in the case when they turn out inaccurate. The developed method was tested for real values of ship rolling simulated by values computed by means of accurate numerical methods.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2004, 2 (74); 315-328
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł

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