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Wyszukujesz frazę "vibration characteristic" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
An experimental study of the effects of cylinder lubricating oils on the vibration characteristics of a two-stroke low-speed marine diesel engine
Autorzy:
Wu, Gang
Jiang, Guodong
Chen, Changsheng
Jiang, Guohe
Pu, Xigang
Chen, Biwen
Powiązania:
https://bibliotekanauki.pl/articles/34603764.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
two-stroke
low-speed marine diesel engine
cylinder lubricating oils
vibration characteristic
condition monitoring
Opis:
Two-stroke, low-speed diesel engines are widely used in large ships due to their good performance and fuel economy. However, there have been few studies of the effects of lubricating oils on the vibration of two-stroke, low-speed diesel engines. In this work, the effects of three different lubricating oils on the vibration characteristics of a low-speed engine are investigated, using the frequency domain, time-frequency domain, fast Fourier transform (FFT) and short-time Fourier transform (STFT) methods. The results show that non-invasive condition monitoring of the wear to a cylinder liner in a low-speed marine engine can be successfully achieved based on vibration signals. Both the FFT and STFT methods are capable of capturing information about combustion in the cylinder online in real time, and the STFT method also provides the ability to visualise the results with more comprehensive information. From the online condition monitoring of vibration signals, cylinder lubricants with medium viscosity and medium alkali content are found to have the best wear protection properties. This result is consistent with those of an elemental analysis of cylinder lubrication properties and an analysis of the data measured from a piston lifted from the cylinder after 300 h of engine operation.
Źródło:
Polish Maritime Research; 2023, 4; 92-101
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The control of stability of a column subjected to specific load
Autorzy:
Sokół, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/122488.pdf
Data publikacji:
2019
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
vibration
vibration control
stability
piezoceramic
characteristic curve
kontrola stabilności
wibracja
kontrola wibracji
element piezoceramiczny
Opis:
In this paper the problem of vibration control of a multi-member column subjected to the specific load is investigated. The vibration control is realized with the use of the piezoceramic element in the form of a rod that is connected to the host structure by means of the pins strengthened by rotational springs. The Hamilton’s principle is used during formulation of the boundary problem. The results of the numerical simulations are focused on the correction of the characteristic curves shape at a different radius of the loading head.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2019, 18, 4; 85-94
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vibration isolators test bench
Autorzy:
Pobedin, A.
Kosov, O.
Shekhovtsov, K.
Powiązania:
https://bibliotekanauki.pl/articles/244493.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
vibration isolator
test bench
vehicle cabin
suspension
testing
elastic and damping characteristic
Opis:
The description of the scheme and design of the test bench for testing vibration isolators intended for use in the vehicle's cabin suspension. Test bench construction allows to implement a wide range of loadings on vibration isolator of the vehicle cabin, to investigate the impact of the loading's arm changing and to perform analysis of the vibration isolator’s elastic and damping characteristics changing impact on cushioning quality. Variant of the test bench construction modernization, which can allow applying typical exploitation loads, which include vertical and lateral components, is described. We propose a scheme of forced oscillations excitation system on the test bench by cam-eccentric mechanism. It includes a DC motor with stepless frequency regulation and with cams of different shape on its shaft, which affect the contact surface of the test bench's vertical H-beam of a rocker arm. We also propose a scheme of forced oscillations excitation system on the test bench by inertial exciter. It includes a DC motor with stepless frequency regulation with inertial vibration exciter on its shaft, which consists of a mass, placed eccentrically relative to the shaft axis. There are two variants of the test bench scheme – with the forced oscillations excitation device and without it.
Źródło:
Journal of KONES; 2011, 18, 1; 457-462
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of natural frequency of flexural vibrations of a single-span beam with the consideration of Timoshenko effect
Autorzy:
Jaroszewicz, J.
Łukaszewicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/950070.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
beam
boundary value problem
transversal vibration
Timoshenko effect
FEM
Cauchy function
characteristic series methods
Opis:
This paper presents general solution of boundary value problem for constant cross-section Timoshenko beams with four typical boundary conditions. The authors have taken into consideration rotational inertia and shear strain by using the theory of influence by Cauchy function and characteristic series. The boundary value problem of transverse vibration has been formulated and solved. The characteristic equations considering the exact bending theory have been obtained for four cases: the clamped boundary conditions; a simply supported beam and clamped on the other side; a simply supported beam; a cantilever beam. The obtained estimators of fundamental natural frequency take into account mass and elastic characteristics of beams and Timoshenko effect. The results of calculations prove high convergence of the estimators to the exact values which were calculated by Timoshenko who used Bessel functions. Characteristic series having an alternating sign power series show good convergence. As it is shown in the paper, the error lower than 5% was obtained after taking into account only two first significant terms of the series. It was proved that neglecting the Timoshenko effect in case of short beams of rectangular section with the ratio of their length to their height equal 6 leads to the errors of calculated natural frequency: 5%÷12%.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2018, 21(3); 215-232
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Load by a force directed towards a positive pole in the aspect of studies on vibrations of a column with crack
Autorzy:
Sokół, K.
Uzny, S.
Powiązania:
https://bibliotekanauki.pl/articles/127900.pdf
Data publikacji:
2016
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
column
crack
natural vibration
instability
characteristic curves
kolumna
pęknięcie
drgania własne
niestateczność
krzywe charakterystyczne
Opis:
In this paper the results of numerical studies on natural vibration frequency and stability of a slender supporting system loaded by external force directed towards a positive pole are presented. In the investigated structure the failure in the form of crack is present. The boundary problem is formulated on the basis of the principle of minimum action – Hamilton’s principle. The results in the non-dimensional form are plotted as the characteristic curves in the external load – natural vibration frequency plane as well as the maximum loading capacity is discussed.
Źródło:
Vibrations in Physical Systems; 2016, 27; 325-332
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Object and operation supported maintenance for mining equipment
Obiektowo i eksploatacyjnie wspomagane utrzymanie górniczego wyposażenia
Autorzy:
Bartelmus, W.
Powiązania:
https://bibliotekanauki.pl/articles/89158.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
condition monitoring
characteristic frequencies
vibration
load susceptibility characteristics
mining machinery/equipment
maintenance
object support
operation support
Opis:
The paper aroused in answer to discussion in Mining Magazine (MM) September 2011 and July/August 2013. The paper shows that discussion given in the MM issue July/August 2013 does not fulfill expectations expressed in MM issue 2011. The presented paper is the review on maintenance that is based on condition monitoring as tool for detection of faults and failure prevention. Fault and failure are regarded as inevitable during the machine operation as the process of wear and the process of degradation. The question is, if one can influence the wear and degradation process, using condition monitoring. The paper will present technology (in reference to cited papers) which demonstrates that the use of the proper method can influence the wear and machine degradation process, using proper condition monitoring techniques and knowing scenarios of wear and degradation process, the maintenance can be rationalized. The presented paper shows possible improvements which are needed to fulfill expectations expressed in MM September 2011 and they are not taken into consideration in MM July/August 3013. These improvements can be fulfilling on the bases of object and operation supported maintenance.
Artykuł powstał w odpowiedzi na dyskusję w Mining Magazine (MM) wrzesień 2011 i lipiec/sierpień 2013. Artykuł pokazuje, że dyskusja przedstawiona w MM 2013 nie spełnia oczekiwań wyrażonych w MM wydanie 2011. Przedstawiana praca jest przeglądem na temat obsługi maszyn, która bazuje na monitorowaniu jako narzędzie dla detekcji uszkodzeń i ich zapobieganiu. Uszkodzenia są uważane jako nieuchronne w eksploatacji jako proces zużycia i degradacji. Istnieje pytanie czy można wpłynąć na proces zużycia i degradacji wykorzystując monitorowanie stanu. Artykuł przedstawił technologię (w odniesieniu do cytowanych prac), które pokazują, że wykorzystując monitorowanie i znając scenariusze zużycia i proces degradacji można racjonalizować eksploatację. Przedstawiony artykuł pokazuje możliwe ulepszenia, które są potrzebne, aby spełnić oczekiwania wyrażone w MM wrzesień 2011, a które nie są brane pod uwagę w MM 2013. Te ulepszenia mogą być spełnione na podstawie wspomagania wnioskowania wynikającego z znajomości cech obiektu i warunków eksploatacji.
Źródło:
Mining Science; 2014, 21; 7-21
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary assessment of vibration impacts generated by the public transport systems on pregnant women based on subjective reactions
Autorzy:
Kromka-Szydek, M.
Dziechciowski, Z.
Tyrpin, P.
Powiązania:
https://bibliotekanauki.pl/articles/307544.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
kobieta ciężarna
wibracje ciała
transport publiczny
środki transportu
pregnant women
whole body vibration
vibration discomfort threshold
amplitude-frequency characteristic
public transport
means of transport
Opis:
Research efforts summarised in this study were a part of preliminary investigation to evaluate the impact of pregnant women’s exposure to vibrations generated by public transport system when using. Methods: The assessment of the problem and discomfort for pregnant women, caused by the public transportation is based on a questionnaire including questions relating to the women’s subjective feelings on well-being or discomfort when exposed to vibration during the ride in passenger cars or when using means of public transport. In the second stage of investigation, vibrations transmitted onto a sitting person during the tram or car ride were measured. Results: The survey shows that when travelling on a tram the women complained mostly of digestive or neurological disorders, during the car ride they suffered most acutely from digestive disorders, sensed enhanced foetus movements and reported problems with the osteoarticular system. Amplitude-frequency characteristics of the investigated vehicle types reveal that vibration amplitudes registered during the ride in a motor vehicle are higher than on tram (in the analysed frequency range). Furthermore, vibration accelerations in the z-axis direction registered during the tram ride exceed the vibration discomfort threshold, particularly for the 1/3 octave bands 5 and 6.3 Hz. These are frequency ranges corresponding to resonance frequencies of vital organs in the abdominal cavity (4.5–10 Hz). Conclusions: Correlating these results with frequencies reported in literature associated with subjective human responses to vibration, shows that pregnant women using public transport are likely to suffer from a variety of ailments caused by vibrations generated during the ride.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 1; 79-92
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free vibrations of the partially tensioned geometrically non-linear system subjected to Euler’s load
Autorzy:
Uzny, S.
Sokół, K.
Osadnik, M.
Powiązania:
https://bibliotekanauki.pl/articles/127651.pdf
Data publikacji:
2016
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
column
Bernoulli-Euler's theory
free vibration frequency
nonlinear system
characteristic curves
amplitude of vibration
nonlinear component of free vibrations frequency
kolumna
teoria Eulera-Bernoulliego
częstotliwość drgań własnych
układ nieliniowy
krzywe charakterystyczne
amplituda drgań
nieliniowa składowa częstości drgań własnych
Opis:
In this study the fixed-fixed column subjected to axial Euler’s load has been investigated. The load is placed between the fixed ends of the structure and its location can be changed along column’s length. The boundary problem of free vibrations of the mentioned system has been formulated on the basis of Bernoulli – Euler theory and taking into account non-linear axial deformation relationship. Due to non-linear expressions the solution of the problem was done with small parameter method. In the paper the change of the first vibration frequency in relation to location and magnitude of the loading force was obtained. The relationship between natural vibration frequency and the amplitude is also discussed.
Źródło:
Vibrations in Physical Systems; 2016, 27; 399-406
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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