Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "vibrations" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 679
Tytuł:
2D and 3D time-frequency dynamic characteristics in the quality assessment of welded joints
Autorzy:
Szeleziński, A.
Muc, A.
Murawski, L.
Powiązania:
https://bibliotekanauki.pl/articles/135313.pdf
Data publikacji:
2018
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
welding
welded joints
non-destructive testing
NDT
SHM
vibrations
time-frequency characteristics
Opis:
The authors of this article have been looking for new parameters and dynamic characteristics which can be applied to the non-destructive testing of welded joints. All the characteristics have been based on the recorded data generated during the vibration tests of welded joints both with and without failures. This article has dealt with the methods of assessing welded joints using either 2D or 3D time-frequency dynamic characteristics. The calculation procedure that was used for analyzing the simultaneous changes of the response modules, registered by acceleration sensors, has been presented. The vibration amplitudes were transformed into a function of time and frequency (simultaneously) and presented over 2D or 3D time-frequency characteristics. The analyses of the characteristics were performed for a plate without a welded joint, for a plate with a non-defective welded joint and for a plate with a defective welded joint caused by edge bonding. Having analyzed and registered the 2D or 3D time-frequency dynamic characteristics it could be noticed that by presenting the responses, analyzed simultaneously against time and frequency, allowed for the evaluation of whether the examined system maintained non-linearity and, at the same time, allowed for the quality of the welded joint to be indirectly assessed. The proposed measurement parameters of the quality of a welded joint can be defined as a dispersion of the colors from the obtained characteristics. The faults (and the vibration nonlinearity) of the welded joints will be bigger if the dispersion is greater.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2018, 56 (128); 41-46
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison of human physical models based on the distribution of power in a dynamic structure in the case of hand-arm vibrations
Autorzy:
Dobry, M. W.
Hermann, T.
Powiązania:
https://bibliotekanauki.pl/articles/280538.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
hand-arm vibrations
biomechanical system
power distribution
Opis:
The main aim of this study is to present an energy comparison of two human physical models taking into account hand-arm vibrations, which are based on the power distribution in their dynamic structure. The method used in the study takes advantage of a close relationship between the dynamics of the systems and energy-related phenomena that occur within them. The energy comparison of the two human physical models required construction of energy models of a Human-Tool system and finding their solutions. For this purpose, programs have been developed using the MATLAB/simulink software to simulate power distribution in the systems. The simulation revealed a discrepancy between the two models in terms of three types of powers and globally in the system as a whole.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 1; 3-13
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison of human physical models used in the ISO 10068:2012 standard based on power distribution. Part 2
Autorzy:
Dobry, M. W.
Hermann, T.
Powiązania:
https://bibliotekanauki.pl/articles/127696.pdf
Data publikacji:
2014
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
biomechanical system
energy flow
energy method
hand-arm vibrations
układ biomechaniczny
przepływ energii
metoda energetyczna
wibracje przenoszone na kończyny górne
Opis:
This article is a continuation of the article entitled „A comparison of human physical models used in the ISO 10068:2012 standard based on power distribution – Part 1” [5], which presented a method of energybased assessment of two human physical models. The first article revealed a discrepancy between the models in terms of three types of power and the total power. The focus of the present study was to determine the order of energy inputs in the dynamic structure and link different types of power to potential threats they pose to human health. Additionally, differences between the models were discussed.
Źródło:
Vibrations in Physical Systems; 2014, 26; 57-64
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A design of piezoelectric vibration absorber with the capacitive adjustment
Autorzy:
Pietrzakowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1986963.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
vibrations
semi-active damping
piezoelectric absorber
capacitive shunting
Opis:
In the paper the problem of vibration damping via piezoelectric absorbers capacitively shunted is studied. The considered system is a simply supported beam with the absorber composed of piezoceramic patches joined by means of brackets in a uniform distance from the beam surface symmetrically on both sides of the beam. Due to the applied damping strategy piezoceramic actuators are shunted with a changeable capacitor in the external circuit to tune the resonance frequencies of the system. The analysis is completed with results of numerical simulations.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 3; 363-369
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A discrete-continuous method of mechanical system modelling
Autorzy:
Hein, R.
Powiązania:
https://bibliotekanauki.pl/articles/258662.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
modelling
mechanical system
dynamic systems
vibrations
hybrid modelling methods
Opis:
The paper describes a discrete-continuous method of dynamic system modelling. The presented approach is hybrid in its nature, as it combines the advantages of spatial discretization methods with those of continuous system modelling methods. In the proposed method, a three-dimensional system is discretised in two directions only, with the third direction remaining continuous. The thus obtained discrete-continuous model is described by a set of coupled partial differential equations, derived using the rigid finite element method (RFEM). For this purpose, firstly the general differential equations are written. Then these equations are converted into difference equations. The derived equations, expressed in matrix form, allow to create a global matrix for the whole system. They are solved using the distributed transfer function method. The proposed approach is illustrated with the examples of a simple beam fixed at both ends and a simply supported plate.
Źródło:
Polish Maritime Research; 2017, S 1; 97-107
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Fundamental Study on the Free Vibration of Geometrical Nonlinear Cantlever Beam using an Exact Solution and Experimental Investigation
Autorzy:
Jamal-Omidi, M.
Shayanmehr, M.
Sazesh, S.
Powiązania:
https://bibliotekanauki.pl/articles/139743.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cantilever beam
geometrical nonlinearity
free vibrations
exact solution
experimental test
belka wspornikowa
nieliniowość geometryczna
drgania swobodne
dokładne rozwiązanie
test doświadczalny
Opis:
Two fundamental challenges in investigation of nonlinear behavior of cantilever beam are the reliability of developed theory in facing with the reality and selecting the proper assumptions for solving the theory-provided equation. In this study, one of the most applicable theory and assumption for analyzing the nonlinear behavior of the cantilever beam is examined analytically and experimentally. The theory is concerned with the slender inextensible cantilever beam with large deformation nonlinearity, and the assumption is using the first-mode discretization in dealing with the partial differential equation provided by the theory. In the analytical study, firstly the equation of motion is derived based on the theory of large deformable inextensible beam. Then, the partial differential equation of motion is discretized using the Galerkin method via the assumption of the first mode. An exact solution to the obtained nonlinear ordinary differential equation is developed, because the available semi analytical and approximated methods, due to their limitations, are not always sufficiently reliable. Finally, an experiment set-up is developed to measure the nonlinear frequency of oscillations of an aluminum beam within a domain of initial displacement. The results show that the proposed analytical method has excellent convergence with experimental data.
Źródło:
Archive of Mechanical Engineering; 2018, LXV, 1; 65-82
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A homogenization procedure and a physical discrete model for geometrically nonlinear transverse vibrations of a clamped beam made of a functionally graded material
Autorzy:
Rahmouni, A.
Benamar, R.
Powiązania:
https://bibliotekanauki.pl/articles/329510.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
discrete system
clamped beam
nonlinear transverse vibrations
FGMs
homogenization procedure
system dyskretny
belka
drgania poprzeczne
funkcjonalny materiał gradientowy
Opis:
Functionally graded materials are used in aircrafts, space vehicles and defence industries because of their good thermal resistance. Geometrically nonlinear free vibration of a functionally graded beam with clamped ends (FGCB) is modeled here by an N-dof discrete system presenting an equivalent isotropic beam, with effective bending and axial stiffness parameters obtained via a homogenization procedure. The discrete model is made of N masses placed at the ends of solid bars connected by rotational springs, presenting the flexural rigidity. Transverse displacements of the bar ends induce a variation in their lengths giving rise to axial forces modeled by longitudinal springs. The nonlinear semi-analytical model previously developed is used to reduce the vibration problem, via application of Hamilton’s principle and spectral analysis, to a nonlinear algebraic system involving the mass and rigidity tensors mij and kij and the nonlinearity tensor bijkl. The material properties of the (FGCB) examined is assumed to be graded according to a power rule of mixture in the thickness direction. The fundamental nonlinear frequency parameters found for the (FGCB) are in a good agreement with previously published results showing the validity of the present equivalent discrete model and its availability for further applications to non-uniform beam.
Źródło:
Diagnostyka; 2017, 18, 3; 15-20
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for identification of non-coaxiality in engine shaft lines of a selected type of naval ships
Autorzy:
Grządziela, A.
Musiał, J.
Muślewski, Ł.
Pająk, M.
Powiązania:
https://bibliotekanauki.pl/articles/260536.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
shaft lines
vibrations
non-coaxiality identification
signal analysis
Opis:
A correctly designed machine is characteristic of low vibration values. However wear processes occur during its operation. They are accompanied by a lack of balance of its rotating parts and elements, which results in non-coaxiality of shafts. For this reason energy and dynamic load resulting from machine vibrations grows. In this case cause and effect are mutually connected by feedback, that inevitably leads to occurrence of a failure. This paper presents results of investigations carried out on the basis of vibration analysis of propulsion systems installed on 207P minesweepers. In view of specific features of their operation it is very important to ensure high level of reliability for them. For this reason was done an attempt to develop a method intended for identifying non-coaxiality of shaft line systems of engines propelling the ships. 16 characteristic features of recorded vibration signals were selected. As any of them has not satisfied criteria assigned to features which unambiguously determine state of reliability of shaft line systems, the investigations have been continued and as a result a novel method for non-coaxiality identification was proposed. The method consists in determining unserviceability clusters and assumes that characteristic features are of a concentrated character. This way a non-coaxiality of main engine shaft lines of 207P minesweepers could be detected. This paper presents the proposed method and results of its application to the case in question.
Źródło:
Polish Maritime Research; 2015, 1; 65-71
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A multimode approach to geometrically non-linear forced vibration of beams carrying point masses
Autorzy:
Fakhreddine, Hatim
Adri, Ahmed
Chajdi, Mohcine
Rifai, Said
Benamar, Rhali
Powiązania:
https://bibliotekanauki.pl/articles/328557.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
geometrical non-linearity
forced vibrations
multimode approach
stress distribution
point mass
nieliniowość geometryczna
drgania wymuszone
rozkład naprężeń
Opis:
The present work deals with the geometrically non-linear forced vibrations of beams carrying a concentric mass under different end conditions. Considering the axial strain energy and expanding the transverse displacement in the form of a finite series of spatial functions, the application of Hamilton's principle reduces the vibration problem to a non-linear algebraic system solved by an approximate method developed previously. In order to validate the approach, comparisons are made of the present solutions with those previously obtained by the finite element method. Focus is made here on the analysis of the non-linear stress distribution in the beam with an attached mass. The non-linear forced deflection shapes and their corresponding curvatures are presented for different magnitudes of the attached mass, different excitation levels and different vibration amplitudes.
Źródło:
Diagnostyka; 2020, 21, 4; 23-33
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new design of gearboxes with reduced vibration and noise levels
Konstrukcja przekładni zębatych o obniżonym poziomie drgań i hałasu
Autorzy:
Jedliński, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/329244.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
reduce vibrations
reduced nosie
vibration-damping element
redukcja drgań
redukcja hałasu
wibroizolator
Opis:
The paper gives an overview of previous trends in development of silent-running gearboxes and presents solutions enabling vibration and noise reduction. Advantages and disadvantages of these solutions are discussed. In addition, the paper describes a new original gear design which enables reducing gear vibration and noise without changing gear contact conditions.
W pracy przedstawiono dotychczasowe kierunki rozwoju konstrukcji cichobieżnych przekładni zębatych oraz szczegółowe rozwiązania, pozwalające na obniżenie ich drgań i hałasu. Wskazano na zalety i wady tych rozwiązań. Zaproponowano nową autorską konstrukcję, umożliwiającą tłumienie drgań i hałasu przekładni zębatych bez zmiany warunków współpracy kół zębatych.
Źródło:
Diagnostyka; 2016, 17, 4; 93-98
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new dynamic model for a rotating beam carrying extra partially distributed mass
Autorzy:
Altınkaynak, A.
Gürgöze, M.
Powiązania:
https://bibliotekanauki.pl/articles/38605374.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
mechanical vibrations
model analysis
rotating cantilever beam
partially distributed mass
radial basis functions-based meshless method
Opis:
In this paper, a new dynamic model for the vibration analysis of an inwardoriented rotating cantilever beam with extra distributed mass was presented. The derived differential equation of motion was solved using the meshless methods of generalizedMultiquadric Radial Basis Function (RBF) and the eigenfrequencies of the system were determined. The same problem was also modeled using the finite element method and the results were compared to validate the accuracy of the proposed model. Later, the effect of the partially distributed mass amount and location on the eigenfrequencies was studied for various beam lengths. The results showed that the eigenfrequency at a constant rotational speed mostly decreased unless the mass was located at the free end of the beam. The location of the mass had a greater effect on the first eigenfrequency compared to the second and third eigenfrequencies. A joint dimensionless eigenfrequency was found at a specific rotational speed regardless of the distributed mass. Nearly constant dimensionless eigenfrequencies could be obtained for a wide range of rotational speeds by adjusting the distributed mass.
Źródło:
Archives of Mechanics; 2020, 72, 4; 307-321
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Power Transformer as a Source of Noise
Autorzy:
Zawieska, W. M.
Powiązania:
https://bibliotekanauki.pl/articles/90466.pdf
Data publikacji:
2007
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
power transformer
noise reduction
active methods
transformer modeling
rectangular plate vibrations
transformer noise
vibroacoustic analysis
Opis:
This article presents selected results of analyses and simulations carried out as part of research performed at the Central Institute of Labor Protection – the National Research Institute (CIOP-PIB) in connection with the development of a system for active reduction of noise emitted by high power electricity transformers. This analysis covers the transformer as a source of noise as well as a mathematical description of the phenomenon of radiation of vibroacoustic energy through a transformer enclosure modeled as a vibrating rectangular plate. Also described is an acoustic model of the transformer in the form of an array of loudspeakers.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2007, 13, 4; 381-389
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A semi-active control of lateral vibrations of the overhung rotor using dampers with the magneto-rheological fluid
Autorzy:
Michajłow, M.
Konowrocki, R.
Szolc, T.
Powiązania:
https://bibliotekanauki.pl/articles/127741.pdf
Data publikacji:
2016
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
overhung rotor-shaft
lateral vibrations
semi-active control
optimal control theory
wał wirnika
drgania poprzeczne
sterowanie półaktywne
teoria sterowania optymalnego
Opis:
In the paper there is proposed an algorithm of an efficient semi-active control of steady-state periodic lateral vibrations of the overhung rotor-shaft system. This algorithm has been developed using fundamentals of the Optimal Control Theory. In the considered system the control is realized by means of the linear dampers with the magneto-rheological fluid built in the bearing housing. The computational example demonstrates possibilities of the applied approach resulting in an additional reduction of out-of-resonance and near-resonance harmonic oscillation amplitudes in comparison with an analogous passive control.
Źródło:
Vibrations in Physical Systems; 2016, 27; 273-280
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A semi-analytic approach to calculating the Strehl ratio for a circularly symmetric system.Part 2: dynamic wavefront
Autorzy:
Castaño-Fernandez, A. B.
Martínez-Finkelshtein, A.
Iskander, D. R.
Powiązania:
https://bibliotekanauki.pl/articles/173593.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
image quality assessment
optical transfer function
longitudinal vibrations
mathematical methods in physics
finite analogs of Fourier transforms
Opis:
Close-form expression for the Strehl ratio calculated in the spatial frequency domain of the optical transfer function (SOTF) is considered for the case of time-varying dynamic optical system that has circular symmetry. Specifically, closed-form expressions for the temporally averaged SOTF are considered, which can be easily evaluated numerically (what we call a semi-analytic solution). As for the case of a static wavefront, described in Part 1 of this work, it is shown that the proposed methods are computationally more efficient than the commonly used approach based on the discrete Fourier transform.
Źródło:
Optica Applicata; 2018, 48, 2; 211-223
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A simple formula for predicting the first natural frequency of transverse vibrations of axially loaded helical springs
Autorzy:
Michalczyk, Krzysztof
Bera, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/282017.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
helical springs
natural frequencies
helical spring vibrations
transverse vibrations
helical spring stability
Opis:
A new formula that allows the first natural frequency of transverse vibrations of axially loaded steel helical springs to be determined has been presented in the paper. The relationship is easy to use and allows finding the first natural frequency of spring vibrations without the necessity of solving analytical or numerical models. According to the authors’ knowledge, this is the first such a formula and, consequently, when this frequency becomes zero, it enables determination of the critical axial force or deflection causing the buckling of the spring. The way of obtaining the described formula is presented in the paper. The results of this formula are compared with those obtained using FEM and experiments. The advantages, drawbacks and limitations of the proposed relationship are also discussed.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 3; 779-790
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 679

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies