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Wyszukujesz frazę "vibration analysis" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Vibrations resonance estimation in marine structures
Autorzy:
Murawski, L.
Powiązania:
https://bibliotekanauki.pl/articles/247863.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
vibration
dynamic analysis
marine structures
propulsion system
crankshaft
resonance
Opis:
Dynamic analyses of marine structures are one of the most important during design process as well as during exploitation. Typically, two parts of vibrations calculations are performed. Firstly, natural vibrations frequencies and modes are determined. Forced vibrations analysis is the second step of calculations. Natural vibrations give us information about possibility (e.g. at which main engine speed) of dangerous vibrations amplitudes (resonances threat). Exact values of vibrations amplitudes are results of forced vibrations analysis. Confidence level (error value) of forced vibration calculations is much lower in comparison to uncertainty of natural vibration analysis. What is more, form engineering practice point of view, natural vibrations frequencies estimation (resonance avoidance) is the most important during dynamic analysis of marine structures with propulsion systems. In the paper some examples of dynamic characteristics estimation and their changing methods (possibility) was presented. Utility of relatively simple models, with low degree of freedom number, was discussed. Modelling methods depending on the analysis target of marine slow-speed crankshafts was presented. Advantages and disadvantages of subcritical and supercritical design of marine propulsion system were discussed. An example of propulsion system natural torsional vibrations simplified analysis was presented. Location of the main torsional resonance is one of the most important decisions during design process of the marine propulsion system. Methods of fast and easy estimation as well as changing possibility of natural vibrations frequencies of marine structures is the main objective of presented paper.
Źródło:
Journal of KONES; 2014, 21, 1; 175-182
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis concerning changes of structure damping in welded joints diagnostics
Autorzy:
Szeleziński, A.
Muc, A.
Murawski, L.
Powiązania:
https://bibliotekanauki.pl/articles/246944.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
diagnostics
welded joints
non-destructive testing
NDT
SHM
vibration
spectrum analysis
damping decrement
Opis:
Among non-destructive testing methods of welded joints, a vibrodiagnostic method is one of the most promising in applications intended for the continuous monitoring of the structure. The accelerometer-recorded responses provide diagnostic information that requires mathematical processing to extract the essential features typical of the tested welded joints and to evaluate their execution. For this purpose, the proposed method was based on the determination of damping decrement in function of time. Due to the complexity of the responses run, a proposed method consisted of calculating the damping decrement using the response approximation with different functions. It has been shown that the changes analysis of damping decrement applied to welded plates enables the assessment of the quality associated with the weld. Attention was also paid to the elements relevant to the study. This work presents the algorithm and exemplary results obtained from the application of proposed method to several selected sample plates with different type of welds. A scientific apparatus, which purpose was to record dynamic characteristics of welded joints was also described.
Źródło:
Journal of KONES; 2017, 24, 4; 313-320
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quality assessment of welded joints using the mean value distribution of amplitude spectrums calculated by the time window method
Autorzy:
Szeleziński, A.
Muc, A.
Murawski, L.
Powiązania:
https://bibliotekanauki.pl/articles/247971.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
diagnostics
welded joints
non-destructive testing
NDT
SHM
vibration
spectrum analysis
time window
mean value
Opis:
In continuous monitoring systems of welded joints of thin-walled structures, a vibrodiagnostic method is the most promising. Its most important advantage is that it is effective and offers the greatest real-time research capabilities. It is used in classic NDT techniques as well as in structural health monitoring during exploitation. This work presents a measurement method of dynamic characteristics of the structure with the use of piezoelectric sensors. The article presents the assumptions concerning the evaluation of welded joints using the analysis of the mean value distribution of the amplitude spectrums calculated by the time window method. The statistical measure used in the form of the mean value is a proposed parameter. The parameter's analysis for a given welded joint may enable an unambiguous assessment of its quality. Attention was paid to the elements important for the study. A calculation algorithm as well as and the exemplary results from the proposed method used for some selected samples with different welds is included in the article. The work contains the description of the scientific apparatus to register dynamic characteristics in case of welded joints. The results of the tests show that the analysis of the distribution of mean value for amplitude spectrums calculated by the time window method indicates that they differ markedly depending on the welds, indicating their quality and defects that are associated with them.
Źródło:
Journal of KONES; 2017, 24, 2; 263-270
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The errors of the numerical calculations of dynamic characteristics of cantilever beam mounted on the plate
Autorzy:
Van Doan, D.
Murawski, L.
Powiązania:
https://bibliotekanauki.pl/articles/241883.pdf
Data publikacji:
2018
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
T-Beam
vibration
ship structure
modal analysis
FEM errors
wibracja
struktura statku
analiza modalna
błędy MES
Opis:
The safety, comfort of the crews, stability, economics of the equipment when ship operating is the leading requirement in the field of designing and manufacturing marine structure and machinery. As a result, all parts of the ships must be tested and inspected to meet the basic safety requirements of the shipping association. The design, manufacture, testing in the maritime field in general and shipbuilding sector in particular are expensive, time consuming: such as aerodynamic experiments of the engine, collision test, ship manoeuvring, vibration test and balance of deck beams, hull beams, hatch covers, shafts ...thus experimental works are sometimes impossible. Along with the development of computer science, many numerical models and software programs have been developed to solve these difficult problems. There are many numerical modelling methods, starting with the finite difference method, the boundary element method, the finite element method, the no mesh method, the weight residue or the energy method. The Work will be limited to the analysis of the most popular numerical modelling method - finite element method using Patran and Nastran software. In the first step of our research, T-beam was analysed as a part of ship hull structure (thin-walled structure). The article goes into the analysis of the accuracy of selected numerical models for the natural vibration frequency of the T-beams mounted on the plate. After modelling, calculating the natural frequency of the T-beam using the Patran - Nastran software, the results were compared with the theoretical values. From that, we evaluate the dispersion and error of different numerical models and select the optimal numerical model. Optimal model will be used for modelling full ship hull with superstructure.
Źródło:
Journal of KONES; 2018, 25, 1; 433-440
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Amplitudes spectrum comparison as a method of selecting welded joints
Autorzy:
Szeleziński, A.
Muc, A.
Murawski, L.
Powiązania:
https://bibliotekanauki.pl/articles/27315855.pdf
Data publikacji:
2018
Wydawca:
STE GROUP
Tematy:
diagnostics
welded joints
non-destructive testing
welding defects
edge fusion
vibration
statistical analysis
diagnostyka
złącza spawane
badania nieniszczące
wady spawalnicze
wibracje
analiza statystyczna
Opis:
The paper presents a comparative analysis of non-destructive testing methods used in the assessment of welded joints. The authors describe the methodology of conducting tests on welded plates using the vibration method. On the basis of the FFT analysis of responses from accelerometers, spectral characteristics were calculated, and then used along with statistical measures to develop a comparative method in non-destructive testing of welded joints. This method will make it possible to quickly and easily distinguish plates with non-defective welded joints from plates with faulty welds. The paper presents test results for a non-defective plate weld (sample no. 2202), a plate with defective edge fusion (sample no. 2127) and one with a cracking along the entire sample length (sample no. 2132). The article points out the limitations of the proposed method and the need for further research.
Źródło:
New Trends in Production Engineering; 2018, 1, 1; 703-709
2545-2843
Pojawia się w:
New Trends in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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