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Wyszukujesz frazę "model parameters" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Non-line analysis of stiffness in compression conditions
Autorzy:
Kahsin, M.
Stecki, D.
Powiązania:
https://bibliotekanauki.pl/articles/259810.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
numerical simulations
uncertainty of model parameters
reliability of results
statistical approach
limit load
Opis:
The analyzes were aimed at demonstrating the influence of parameters describing the deformation of the structure on the uncertainty of critical force, and the impact of technological imperfections on stress uncertainty in compression conditions. In a linear buckling analysis, the problem is considered only for the initial, permanent state of the stiffness matrix. In the case of demonstrating the influence of initial deformations on the behavior of the structure under load, it is necessary to visualize changes in stiffness over time. To this end, a non-linear MES analysis was carried out, which will take into account local changes in the stiffness of the model through a gradual increase in the load. Thus, the difference in stiffness is taken into account, which in the linear problem is infinite. The analysis was used to examine the local and global sensitivity of the parameters describing: plating thickness as well as deformation caused by the technological process on the stress value reduced by Huber hypothesis, and the value of normal stress. To take into account the influence of non-specified values of the magnitude of geometric deviations, and their simultaneous influence on the range of obtained results, the Experimental Planning Method and the Surface Method of Answers were used.
Źródło:
Polish Maritime Research; 2018, 2; 100-107
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ranking of toxic compound concentrations as diagnostic parameetrs of marine internal combustion engine
Autorzy:
Zadrąg, R.
Kniaziewicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/259107.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
diagnostic model
Diesel engine
exhaust components
ranking of parameters
Opis:
Changing selected engine structure parameters, especially fuel system parameters, affects the emission of harmful compounds in the exhaust gas. Changes in harmful compound emission are frequently ambiguous, as they highly depend on parameters controlling the combustion process. An additional problem is that simple interactions are frequently accompanied with mutual influence of these parameters. Therefore, we can say about different sensitivity of diagnostic parameters to the same excitations coming from the engine structure but executed at different loading states. When the set of diagnostic parameters is numerous and the values of these parameters are similar, there is a real problem with their correct classification, frequently based on subjective assessment by the analyst. In the article, the authors propose a methodology to classify the recorded diagnostic parameters. In earlier works by the authors [4,6,7], the information capacity index method (the Hellwig method) was proposed as the measure of diagnostic parameter sensitivity. Based on this method, a rankling of diagnostic parameters can be created which divides the set of diagnostic variables into stimulators and destimulators. Novel authors’ approach to the presented problem consists in including nominants, i.e. variables with the most favourable value for the analysed aspect of the research, in the set of diagnostic variables. This normalisation of the set is believed to be helpful for making a diagnostic decision free from analyst’s arbitrariness. The zero unitarization method can also be helpful in creating diagnostic tests.
Źródło:
Polish Maritime Research; 2018, S 1; 234-242
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analysis of the Tvergaard parameters at low initial stress triaxiality for S235JR steel
Autorzy:
Kossakowski, P. G.
Powiązania:
https://bibliotekanauki.pl/articles/260394.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
Tvergaard parameters
Gurson-Tvergaard-Needleman material model
GTN
S235JR steel
Opis:
This paper discusses the influence of the Tvergaard parameters, qi, which are basic constants of the Gurson-Tvergaard- Needleman (GTN) material model, on the numerically simulated load-carrying capacity of tensile elements made of S235JR steel. The elements were considered to be under static tension at low initial stress triaxiality σm/σe = 1/3. Two sets of the Tvergaard parameters qi were analyzed: those typical of structural steels and those dependent on material strength properties. The results showed that the Tvergaard parameters, qi, had influence on the load-carrying capacity of tensile elements at low initial stress triaxiality. They affected the strength curves and the changes in the void volume fractions determined for S235JR steel elements
Źródło:
Polish Maritime Research; 2014, 4; 100-107
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parameters identification of the flexible fin kinematics model using vision and Genetic Algorithms
Autorzy:
Jurczyk, Karolina
Piskur, Paweł
Szymak, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/259505.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
Biomimetic Underwater Vehicle
flexible fin kinematics model
parameters identification using vision
Genetic Algorithm
Opis:
Recently a new type of autonomous underwater vehicle uses artificial fins to imitate the movements of marine animals, e.g. fish. These vehicles are biomimetic and their driving system is an undulating propulsion. There are two main methods of reproducing undulating motion. The first method uses a flexible tail fin, which is connected to a rigid hull by a movable axis. The second method is based on the synchronised operation of several mechanical joints to imitate the tail movement that can be observed among real marine animals such as fish. This paper will examine the first method of reproducing tail fin movement. The goal of the research presented in the paper is to identify the parameters of the one-piece flexible fin kinematics model. The model needs further analysis, e.g. using it with Computational Fluid Dynamics (CFD) in order to select the most suitable prototype for a Biomimetic Underwater Vehicle (BUV). The background of the work is explained in the first section of the paper and the kinematic model for the flexible fin is described in the next section. The following section is entitled Materials and Methods, and includes a description of a laboratory test of a water tunnel, a description of a Vision Algorithm (VA)which was used to determine the positions of the fin, and a Genetic Algorithm (GA) which was used to find the parameters of the kinematic fin. In the next section, the results of the research are presented and discussed. At the end of the paper, the summary including main conclusions and a schedule of the future research is inserted.
Źródło:
Polish Maritime Research; 2020, 2; 39-47
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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