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Wyświetlanie 1-10 z 63
Tytuł:
Mechanical vibrations: recent trends and engineering applications
Autorzy:
Garus, Sebastian
Błachowski, Bartłomiej
Sochacki, Wojciech
Jaskot, Anna
Kwiatoń, Paweł
Ostrowski, Mariusz
Šofer, Michal
Kapitaniak, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2090733.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mechanical vibration
energy harvesting
modal analysis
granular materials
wibracje mechaniczne
zbieranie energii
analiza modalna
materiały ziarniste
Opis:
Although the study of oscillatory motion has a long history, going back four centuries, it is still an active subject of scientificr esearch. In this review paper prospective research directions in the field of mechanical vibrations were pointed out. Four groups of important issues in which advanced research is conducted were discussed. The first are energy harvester devices, thanks to which we can obtain or save significant amounts of energy, and thus reduce the amount of greenhouse gases. The next discussed issue helps in the design of structures using vibrations and describes the algorithms that allow to identify and search for optimal parameters for the devices being developed. The next section describes vibration in multi-body systems and modal analysis, which are key to understanding the phenomena in vibrating machines. The last part describes the properties of granulated materials from which modern, intelligent vacuum-packed particles are made. They are used, for example, as intelligent vibration damping devices.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 1; e140351, 1--12
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analyzing mechanical vibrations of an aircraft opposed piston engine
Autorzy:
Biały, Michał
Grabowski, Łukasz
Skórzyński, Bartłomiej
Barański, Grzegorz
Majczak, Adam
Powiązania:
https://bibliotekanauki.pl/articles/2097574.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
DIAdem
mechanical vibrations
opposed pistons
PZL-100
vibroacoustics
drgania mechaniczne
tłoki przeciwstawne
wibroakustyka
Opis:
The paper presents the results of the bench tests to measure mechanical vibrations of a new aircraft opposed piston engine with reciprocating pistons. The PLZ-100 engine is a three-cylinder, six-piston, two-shaft drive unit with a two-stroke diesel cycle. This type of engine is dedicated for powering light aircraft, e.g. autogyros. The tests were carried out on a test bench at the Lublin University of Technology. The engine was loaded with constant torque, for several fixed values of rotational speed of a crankshaft. The angle of the start of diesel injection was changed for each of the rotational speeds. The mechanical vibrations that accompanied the operation of this drive unit were recorded with three measurement transducers and a National Instruments conditioning system. Each of the transducers was mounted on a different axis of the engine. The signals were analyzed from their diagrams with the DIAdem software. The results were the diagrams of effective speed and vibration acceleration to conduct a vibration-acoustic evaluation of the PLZ-100, detect and prevent various types of defects or failures.
Źródło:
Combustion Engines; 2021, 60, 4; 3--7
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Support with mechanical vibrations of welding processes ‒ review of own research
Autorzy:
Krajewski, Arkadiusz
Kołodziejczak, Paweł
Cegielski, Paweł
Grześ, Jarosław
Powiązania:
https://bibliotekanauki.pl/articles/1819229.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
spawanie
wibracje mechaniczne
wibracje ultradźwiękowe
wibracje akustyczne
śrutowanie
MIG
MAG
TIG
LW
RW
welding
mechanical vibration
ultrasonic vibration
acoustic vibration
shot-blasting
Opis:
The article discusses the most important original achievements in the use of high-power mechanical vibrations with low and ultrasonic frequency in various welding processes such as (131) MIG, (135) MAG, (141) TIG, (21) RW, (522) LW, (45) diffusion welding and (924) brazing in relation to various basic materials such as structural steel and aluminum alloys. Mechanical vibrations were introduced by means of ultrasonic vibrating systems and using the shot-blasting process, as well as acoustic influence. As part of the comparative research, the structure and hardness analysis of HV0.1 was presented. The obtained results indicate that both low-frequency and ultrasonic frequency vibrations significantly change the properties of the resulting structures affected by mechanical vibrations. The scale of these changes varies depending on the frequency and parameters specific to each of the welding processes used. The obtained results allow us to conclude that the skilful application of mechanical vibrations accompanying welding processes can contribute to the reduction of grain sizes, to change the depth or width of penetration and to lowering hardness in the sensitive heat affected zone area.
Źródło:
Welding Technology Review; 2021, 93, 3; 57--73
0033-2364
2449-7959
Pojawia się w:
Welding Technology Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time-Frequency Analysis of Mechanical Vibrations of the Dry Type Power Transformer Core
Autorzy:
Borucki, S.
Powiązania:
https://bibliotekanauki.pl/articles/1493019.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.40.-r
43.40.Vn
43.58.Wc
Opis:
The paper presents research results referring to the development of a non-invasive method of assessment of the power transformer core technical condition based on the analysis of the mechanical vibrations registered. It characterizes the power object under study, the measuring system used and the developed methodology of assessment of the core pressing degree using the vibroacoustic method. The original results of the time-frequency analysis of the vibroacoustic signals presented in the paper were obtained during switching on a real 800 kVA dry type power transformer in laboratory conditions. The analysis of the signals registered was carried out for three states of its operation: the core pressed by the manufacturer, the core with loose screws fixing the upper yoke and the core with separated upper yoke beams.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 571-574
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modified laplace based variational iteration method for the mechanical vibrations and its applications
Autorzy:
Rehman, Shahida
Hussain, Akhtar
Rahman, Jamshaid Ul
Anjum, Naveed
Munir, Taj
Powiązania:
https://bibliotekanauki.pl/articles/2106003.pdf
Data publikacji:
2022
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
variational iterative method
nonlinear oscillator
Laplace transform
Opis:
In this paper, we are putting forward the periodic solution of non-linear oscillators by means of variational iterative method (VIM) using Laplace transform. Here, we present a comparative study of the new technique based on Laplace transform and the previous tech-niques of maximum minimum approach (MMA) and amplitude frequency formulation (AFF) for the analytical results. For the non-linear oscillators, MMA, AFF and VIM by Laplace transform give the same analytical results. Comparison of analytical results of VIM by Laplace transform with numerical results by fourth-order Runge–Kutta (RK) method conforms the soundness of the method for solving non-linear oscillators as well as for the time and boundary conditions of the non-linear oscillators.
Źródło:
Acta Mechanica et Automatica; 2022, 16, 2; 98--102
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Harvesting mechanical vibrations energy using nonlinear electromagnetic minigenerators - a survey of concepts and problems
Autorzy:
Kulik, M.
Jagieła, M.
Powiązania:
https://bibliotekanauki.pl/articles/376373.pdf
Data publikacji:
2017
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
energy harvesting
nonlinear resonance
bistability
electromagnetic induction
Opis:
The state of knowledge in the field of conversion of energy of mechanical vibrations into electrical energy using nonlinear electromagnetic generators is presented. The principle of operation of the considered converters is based on the Faraday law. The electromotive force is induced by the relative movement of the coil or permanent magnets under impact of externally applied vibrations. In order to diminish the disadvantages of conventional generators, namely the narrow frequency bandwidth, in recent years the nonlinear systems were introduced that exhibit the nonlinear resonance phenomenon. Broadening the frequency bandwidth, in which the power generated by the system is relatively high, is realized via introduction of nonlinear force into system kinematics. Designing such systems becomes a big challenge. Based on thorough survey of recent publications as well as on own expertise in the field, the work compares a few concepts of nonlinear electromechanical minigenerators in term of their functional characteristics and design problems. Sample calculations of frequency characteristics using time- and frequency-domain models are presented.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2017, 90; 347-358
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Analysis of Mechanical Vibrations and Acoustic Pressure Level οf a Transformer Model
Autorzy:
Boczar, T.
Borucki, S.
Cichon, A.
Lorenc, M.
Powiązania:
https://bibliotekanauki.pl/articles/1811534.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.58.Wc
43.58.Fm
Opis:
The paper presents the results of vibroacoustic investigations and the measurements of the acoustic pressure level (noise) of a transformer model. The measurements were taken at a full transformer load in two operation conditions: at a producer packeted core and at unpacketed core. Unpacketing consisted in loosing the screws pressing the particular core plates. Mechanical vibrations were registered and the acoustic pressure level was measured. The vibroacoustic analysis results are presented in the form of frequency spectra and the results of the acoustic analysis of the transformer under study are shown by determining corrected values of the acoustic pressure level and by a frequency analysis.
Źródło:
Acta Physica Polonica A; 2008, 114, 6A; A-21-A-26
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection of ice states from mechanical vibrations using entropy measurements and machine learning algorithms
Autorzy:
Mejía, Juan C.
Quintero, Héctor F.
Echeverry-Correa, Julián D.
Romero, Carlos A.
Powiązania:
https://bibliotekanauki.pl/articles/327980.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
entropy
vibration
dynamics
permutation
signal processing
entropia
drgania
dynamika
permutacja
przetwarzanie sygnałów
Opis:
Entropy measurements are an accessible tool to perform irregularity and uncertainty measurements present in time series. Particularly in the area of signal processing, Multiscale Permutation Entropy (MPE) is presented as a characterization methodology capable of measuring randomness and non-linear dynamics present in non-stationary signals, such as mechanical vibrations. In this article, we present a robust methodology based on MPE for detection of Internal Combustion Engine (ICE) states. The MPE is combined with Principal Component Analysis (PCA) as a technique for visualization and feature selection and KNearest Neighbors (KNN) as a supervised classifier. The proposed methodology is validated by comparing accuracy and computation time with others presented in the literature. The results allow to appreciate a high effectiveness in the detection of failures in bearings (experiment 1) and ICE states (experiment 2) with a low computational consumption.
Źródło:
Diagnostyka; 2020, 21, 4; 87-94
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in the quality characteristics of raspberry fruit due to mechanical vibrations and storage conditions
Autorzy:
Mazur, Jacek
Panasiewicz, Marian
Zawiślak, Kazimierz
Sobczak, Paweł
Nadulski, Rafał
Łysiak, Grzegorz
Kraśnicka, Kinga
Powiązania:
https://bibliotekanauki.pl/articles/298046.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
raspberry fruits
mechanical impact
juice leakage
Opis:
The paper presents the results of a study investigating a mechanical impact, in the form of vibrations, on the overall quality of raspberry fruits after harvest, in view of the conditions of their transport to the consumer and the processing plant. The degree of compaction of the raspberry fruit layer was determined during a test carried out under laboratory conditions, and the amount of juice leakage, resulting from the vibrations to which the raspberries were subjected, was measured. It was demonstrated that the quantity (mass) of juice leakage was considerably affected by the mechanical impact, in the form of vibrations, exerted on a layer of raspberry fruits. The leakage was smaller in cooled fruits, and significantly greater in fruits that were not subjected to cooling immediately after harvest, and were stored under ambient conditions.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2019, 22(4); 319-328
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of external mechanical vibrations on hydraulic microvalves. Test stand design and preliminary tests
Autorzy:
Stosiak, M.
Towarnicki, K.
Lubecki, A.
Powiązania:
https://bibliotekanauki.pl/articles/1189964.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mikrohydraulika
zawór przelewowy
drgania
pulsacja ciśnienia
microhydraulics
pressure relief valve
vibration
pressure fluctuation
Opis:
Fluid pressure fluctuations in a microhydraulic system can be caused by fluctuations in the rate of fluid delivery, due to the operational kinematics of the micropump’s displacement elements, as well as by external excitations. This paper presents the requirements for microhydraulic systems and indicates the disturbances that can occur during operation. A test stand was designed to identify the impact of external mechanical vibrations on microhydraulic elements. Test stand was equipped with a measuring system to generate and record vibrations and examine their effect on the operation of microhydraulic components. Set parameters and operating conditions of the system during measurements were given. A relief microvalve was chosen, as a representative microhydraulic component. Based on the measurements, additional component derived from external vibrations was identified in frequency spectrum of pressure pulsations.
Źródło:
Interdisciplinary Journal of Engineering Sciences; 2018, 6, 1; 48--52
2300-5874
Pojawia się w:
Interdisciplinary Journal of Engineering Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-10 z 63

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