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Wyszukujesz frazę "vibration effect" wg kryterium: Temat


Wyświetlanie 1-14 z 14
Tytuł:
Optimisation of absorber parameters in the case of stochastic vibrations in a bridge with a deck platform for servicing pipelines
Autorzy:
Grosel, Jacek
Podwórna, Monika
Powiązania:
https://bibliotekanauki.pl/articles/2037668.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
urban network infrastructure
dynamic vibration absorber
DVA
vibration effect
dynamic analysis
Poisson process
random vibration
Opis:
The paper focuses on the problem of optimising the cooperation between a dynamic vibration absorber (DVA) and a structure. The authors analyse a road beam bridge equipped with a working platform (deck) used to service pipelines installed on the structure. The paper studies the problem of choosing the optimal parameters for damping absorbers that reduce the random vibration of a beam subjected to a random sequence of moving forces with a constant velocity. The stochastic properties of the load are modelled by means of a filtering Poisson process. A single-degree-of-freedom (SDOF) absorber model with a multi-degree-of-freedom (MDOF) primary structure model are is considered.
Źródło:
Studia Geotechnica et Mechanica; 2021, 43, s1; 492-500
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effects of constrained cross-specional warping on bending of beams
Wpływ kształtu i skrępowania spaczania przekrojów poprzecznych na zgięcie belek
Autorzy:
Janecki, S.
Powiązania:
https://bibliotekanauki.pl/articles/280084.pdf
Data publikacji:
1998
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
beams
shear effect
vibration
Opis:
The equations of motion for a bent beam of compact cross-section, are presented in this work. They are derived by using of the general methodapplicable to one-dimensional models of continuum. The warping constraint of cross-sections, caused by shearing, has been taken into account. An additional parameter characterizing the form of a cross-section warping function is introduced. Two dimensionless shearing coefficients appear in the given equations. One of them characterizes the constrained shearing, and the other one the free shearing. It has been shown that these coefficients do not depend upon the form of the warping function. In a particular case, if the constraint cross-sectional warping does not appear, then the equation of motion and the constitutive relations are the same as in Timoshenko's theory. A series of important examples illustrating the bending theory of beams is presented in the paper. The form of the warping function and the warping constraint of an arbitrary, compact cross-section has been taken into account in these examples. In a particular case, an equation defining the parameter magnitudes of the thickness shear mode, for a simply supported beam of an arbitrary cross-section, is given. A critical analysis the works of Bickford (1982), Ewing (1990), Leung (1990) and Levinson (1981) has been made.
W pracy przedstawiono równania ruchu belki zginanej o dowolnych jednospójnych przekrojach poprzecznych. Uwzględniono skrępowanie deplanacji przekrojów poprzecznych, spowodowanej nierównomiernym ścinamiem. Wprowadzono dodatkowy parametr charakteryzujący kształy funkcji deplanacji przekrojów poprzecznych belki. W podanych równaniach występują dwa niezależne, bezwymiarowe współćzynniki ścinania. Jeden z nich charakteryzuje ścinanie skrępowane, a drugi ścinanie swobodne. Pokazano, że współczynniki te są niezależne od kształtu funkcji deplanacji. Równania ruchu i związki konstytutywne w szczególnym przypadku deplanacji swobodnej sprowadzają się do równań i związków występujących w teorii Timoshenko. W pracy przedstawiono szereg ważnych przykładów ilustrujących teorie zgięcia belek. Wzięto w nich pod uwagę kształt funkcji deplanacji i skrępowanie deplanacji dowolnych, jednospójnych przekrojów poprzecznych. W szczególnym przypadku podano równanie określające wielkość parametrów postaci drgań ścinania poprzecznego belki (thickness shear mode) swobodnie podpartej, posiadającej dowolny przekrój poprzeczny. Przeprowadzono krytyczną analizę wyników prac Levisona (1981), Bickforda (1982), Ewinga (1990), Leunga (1990).
Źródło:
Journal of Theoretical and Applied Mechanics; 1998, 1; 121-144
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiple regenerative effect governing chatter behaviour after onset
Autorzy:
Sato, H.
Powiązania:
https://bibliotekanauki.pl/articles/99970.pdf
Data publikacji:
2013
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
machine tools
chatter
vibration
regenerative effect
Opis:
Chatter is the self-excited vibration that occurs during cutting. The entire structure of a self-excited vibration comprises two core mechanisms, i.e., stability limit and sustained vibration with finite amplitude after onset. The latter mechanism remained unnoticed until the discovery of the multiple regenerative effect (MRE) in 1980. However, its effects have not yet been recognized correctly. This paper summarizes the problems that could be resolved by considering the MRE in the analysis from the theoretical and practical viewpoints. In conventional stability limit analyses,tool traces never intersect; however, after the onset of chatter in an actual system, traces immediately intersect. This resultsin tool-workpiece separation, chip thickness variation during the separation period, and chip breakage. A solution for equation of motion considering the MRE agrees well with chatter behaviour in actual applications. In addition, the solution yields the phase relationship between the displacement of work motion and the cutting force, although this relationship is not considered in the equation of motion. Further, the relationship between the penetrating cutting speed and the resistive force, confirmed experimentally, is introduced in equation of motion, which verifies the widening of the stability region at low cutting speeds.
Źródło:
Journal of Machine Engineering; 2013, 13, 3; 51-76
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Broadband concept of energy harvesting in beam vibrating systems for powering sensors
Autorzy:
Rysak, A
Müller, M.
Borowiec, M.
Zubrzycki, J.
Litak, G.
Godlewska-Lach, A
Wittstock, V.
Powiązania:
https://bibliotekanauki.pl/articles/957989.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
piezoceramic
energy harvesting
vibration
broadband effect
impacts
Opis:
Recent demand for powering small sensors for wireless health monitoring triggered activities in the field of small size efficient energy harvesting devices. We examine energy harvesting in an aluminium beam with a piezoceramic patch subjected to kinematic harmonic excitation and impacts. Due to a mechanical stopper applied, inducing a hardening effect in the spring characteristic of the beam resonator, we observed a broader frequency range for the fairly large power output. Impact nonlinearities caused sensitivity to initial conditions and appearance of multiple solutions. The occurrence of resonant solution associated with impacts increased efficiency of the energy harvesting process.
Źródło:
Advances in Science and Technology. Research Journal; 2014, 8, 23; 62-67
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
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:
Spatial model of the unsprung wheeled machine’s dynamic system
Autorzy:
Chwastek, S.
Powiązania:
https://bibliotekanauki.pl/articles/241952.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
spatial model
dynamic system
mobile heavy machines
unsprung vehicles
"galloping" effect
"snake meandering” effect
adhesion factor
slipping action
vibration
differential gear
Opis:
Mobile heavy machines as unsprung vehicles exhibit low dissipation ability, hence the ride even at low speeds may give rise to intensive vertical and angular vibration. Vibrations thus produced are mostly in the low-frequency range and hence energy dissipation in tires will reduce the vibration intensity in a minor degree only. Particularly dangerous situations occur when the road wheels break away from the road surface due to the ’galloping’ effect. Kinematic excitation acting on the wheels is mostly uncorrelated stochastic (random) processes, giving rise to the "snake meandering" effect. That implies a major restriction on the ride velocity, which negatively affects the machine performance. The motion of tired wheels will always involve certain slipping. While investigating the feasibility of increasing the efficiency of the vibration reduction systems, one ought to take into account the variable adhesion of road wheels due to different dynamic loading acting on the vehicle axles during the ride. This study investigates the motion of unsprung mobile machines, taking into account the dynamic processes in the driving system under the conditions of the variable adhesion of road wheels. The model of interaction between a tired wheel and the terrain takes into account the relationship between the road wheel adhesion factor and the slipping action, as well as the impacts of the differential gear on distribution of drive torque. The 3D (spatial) model of a backhoe loader is considered. It is a two-axle self-propelled machine on a wheeled chassis. The mathematical model constitutes nonlinear and non-stationary differential equations of motion. Their stability is therefore associated with vibration intensity. Simulations in the time domain were supported by Matlab-Simulink. The purpose of this study is to improve the safety features during the ride of mobile heavy machines, basing on the parametric optimization of the model.
Źródło:
Journal of KONES; 2014, 21, 2; 45-52
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modulation effect of vibration frequency of an unsprung heavy machine under the variable road adhesion conditions
Autorzy:
Chwastek, S.
Powiązania:
https://bibliotekanauki.pl/articles/244951.pdf
Data publikacji:
2013
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
mobile heavy machines
unsprung vehicles
galloping effect
adhesion factor
slipping action
frequency modulation of vibration
Opis:
Mobile heavy machines as unsprung vehicles exhibit low dissipation ability, hence the ride even at low speeds may give rise to intensive vibration. Particularly dangerous situations occur when the road wheels break away from the road surface due to the ’galloping’ effect, being the result of excited vertical and angular vibration of the machine frame in the vertical plane of symmetry. That implies a major restriction on the ride velocity, which negatively impacts on the machine performance. Vibrations thus produced are mostly in the low-frequency range and hence energy dissipation in tyres will reduce the vibration intensity in a minor degree only. The motion of tired wheels will always involve some slipping. While investigating the feasibility of increasing the efficiency of the vibration reduction systems, one ought to take into account the variable adhesion of road wheels due to different dynamic loading acting on the vehicle axles during the ride. Observations of unsprung machines during the ride suggest the occurrence of self-excited vibration. Mobile machines constitute dynamic systems, which can be governed by nonlinear, sometimes non-stationary differential equations of motion. Their stability also depends on intensity of external vibrations. This study investigates the motion of unsprung mobile machines, taking into account the dynamic processes in the driving system under the conditions of the variable adhesion of road wheels. The model of interaction between a tired wheel and the terrain takes into account the relationship between the road wheel adhesion factor and the slipping action. Mathcad supported by Matlab-Simulink and in the frequency domain – simulations in the time domain. The purpose of the simulation procedure was to find the causes of the vibration modulation frequency and determine the conditions triggering the occurrence of self-excited vibrations. Simulations are supported by the analysis of motion stability.
Źródło:
Journal of KONES; 2013, 20, 4; 55-62
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature effect on frequencies of a tapered triangular plate
Autorzy:
Khodiya, Akash
Sharma, Amit
Powiązania:
https://bibliotekanauki.pl/articles/1839862.pdf
Data publikacji:
2021
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
temperature effect
triangle plate
frequency
vibration
częstotliwość
wibracja
metoda Rayleigha-Ritza
gradient termiczny
efekt temperaturowy
Opis:
The two dimensional temperature effect on the vibration is computed for the first time for a clamped triangular plate with two dimensional thickness. In the study we focused on isosceles, right-angled and scalene triangles only. The first three modes of vibration are computed on different variations of plate parameters using the Rayleigh-Ritz method. The objective of the study is to reduce the frequency of the plates. A comparative study of the frequencies with other available results well presents the objective of the study.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2021, 20, 1; 37-48
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Design of Experiments for Statistically Predicting Risk of Adverse Health Effects on Drivers Exposed to Vertical Vibrations
Autorzy:
Ayari, H.
Thomas, M.
Dore, S.
Powiązania:
https://bibliotekanauki.pl/articles/90147.pdf
Data publikacji:
2011
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
adverse health effect
whole-body vibration
spinal loading
finite element analysis
ageing
design of experiments
Opis:
An injury risk factor (IRF), which indicates the risk of adverse health effect to lumbar rachis arising from mechanical vibrations, is developed. Experiments have been conducted that consider acceleration levels at the seat of drivers, posture, morphology, density, damping rate and body mass as independent variables. A parametric finite-element model of the lumbar rachis has been generated. It is shown that the IRF increases with ageing and an IRF of 30% is proposed as a threshold for fatigue purposes. This level is reached if a peak acceleration level greater than 3 m/s2 is applied to a light (55 kg) and an old driver with a low bone density and a damping rate of 20%. This vibration threshold must be reduced to 2.7 m/s2 if the driverʼs weight increases to 75 kg and to 2 m/s2 if the driver is heavy (98 kg).
Źródło:
International Journal of Occupational Safety and Ergonomics; 2011, 17, 3; 221-232
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of positive elevation effect and prediction of vibration velocity of bench blasting vibration
Autorzy:
Zhang, X. J.
An, H. M.
Powiązania:
https://bibliotekanauki.pl/articles/1853676.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
drgania wybuchowe
efekt podniesienia pozytywny
formuła kroku
strzał
kopalnia
blasting vibration
positive elevation effect
step formula
mine
blasting
Opis:
Accurate prediction of blasting vibration should be achieved in mine blasting production practice. It is also a critical problem in the field of blasting vibration control technology research. In this research paper, on the basis of the previous research results and taking account into the reflection principle of elastic wave at the free interface, the authours proposes the blasting seismic wave propagation model. In addition, the blasting positive elevation effect are theoretically explained in detail, and the vibration velocity prediction formula of the positive elevation effect is derived. Finally, the positive elevation effect mechanism and the step (positive) formula are calibrated based on the on-site monitoring data of blasting vibration of Qipanjing Jinou coal mine. In beirf, a theoretical basis is laid by this paper for similar blasting projects.
Źródło:
Archives of Civil Engineering; 2021, 67, 1; 599-618
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free axisymmetric flexural vibrations of circular plate with symmetrically varying mechanical properties supported on elastic foundation
Autorzy:
Magnucki, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/2146562.pdf
Data publikacji:
2020
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
circular plate
elastic foundation
shear effect
axisymmetric flexural vibration
płyta kołowa
podłoże sprężyste
efekt ścinania
osiowosymetryczne drgania giętne
Opis:
The subject of the paper is a circular plate with clamped edge supported on elastic foundation. Mechanical properties of the plate symmetrically vary in its thickness direction. Free axisymmetric flexural vibration problem of the plate with consideration of the shear effect is analytically studied. Two partial differential equations of motion based on the Hamilton principle are obtained. The system of equations is analytically solved and the fundamental natural frequency of axisymmetric vibration for example plates is derived.
Źródło:
Vibrations in Physical Systems; 2020, 31, 2; art. no. 2020217
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zagrożenia obiektów budowlanych wynikające z powstania drgań o charakterze rezonansowym
Dangers to buildings and structures resulting from resonant vibrations
Autorzy:
Marcinowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/163655.pdf
Data publikacji:
2012
Wydawca:
Polski Związek Inżynierów i Techników Budownictwa
Tematy:
projektowanie konstrukcji
obciążenie dynamiczne
wzbudzenie drgań
efekt rezonansu
przykład projektowy
construction designing
dynamic load
vibration excitation
resonance effect
design example
Opis:
W referacie zostały wyeksponowane zagrożenia związane z wystąpieniem drgań o charakterze rezonansowym. Przytoczone zostały typowe okoliczności, w których może dochodzić do wzbudzeń rezonansowych. Referat zilustrowano przykładami wystąpienia drgań o charakterze rezonansowym w istniejących obiektach.
This paper describes hazards resulting from the presence of resonant vibrations. Typical circumstances in which resonant excitation may occur are identified. The paper is illustrated with examples of the occurrence of resonant vibrations in existing structures.
Źródło:
Przegląd Budowlany; 2012, R. 83, nr 5, 5; 129-132
0033-2038
Pojawia się w:
Przegląd Budowlany
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of suspended equipment on the carbody vertical vibration behaviour of high-speed railway vehicles
Wpływ wyposażenia zamontowanego w nadwoziu wagonu na charakterystyki drgań pionowych pojazdu szynowego kolei szybkobieżnych
Autorzy:
Dumitriu, M.
Powiązania:
https://bibliotekanauki.pl/articles/139537.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
railway vehicle
flexible carbody
suspended equipment
vertical vibration
frequency response functions
geometric filtering effect
pojazd szynowy
elastyczne nadwozie wagonu
wyposażenie zawieszone
drgania pionowe
funkcje odpowiedzi częstotliwościowej
zjawisko filtracji geometrycznej
Opis:
The equipment mounted on the carbody chassis of the railway vehicles is a critical component of the vehicle in terms of ride comfort. The reason for that is their large mass, able to visibly influence the vibrations mode of the carbody. The paper examines the influence of the equipment upon the mode of vertical vibrations of the carbody in the high-speed vehicles, reached on the basis of the frequency response functions of the acceleration in three carbody reference points – at the centre and above the bogies. These functions are derived from the numerical simulations developed on a rigid-flexible coupled model, with seven degrees of freedom. As a rule, the results herein prove the influence of the equipment mounting mode (rigid or elastic), along with the speed regime, upon the level of vibrations in the carbody reference points, at the resonance frequency of the symmetrical bending mode. Similarly, it is also demonstrated how the equipment mass and the damping degree of the suspension system affect the level of the vibrations in the carbody.
Wyposażenie zamontowane na podwoziu pudła wagonu kolejowego stanowi krytyczny składnik pojazdu gdy chodzi o komfort jazdy. Powodem jest jego znaczna masa, zdolna w istotny sposób wpływać na drgania pojazdu. W artykule badano wpływ wyposażenia na tryb drgań pionowych nadwozia wagonu kolei szybkobieżnych. Za podstawę przyjęto częstotliwościowe funkcje przyspieszenia wyznaczone w trzech punktach odniesienia – w środku pojazdu i ponad wózkami zwrotnymi. Funkcje te zostały wyznaczone na podstawie symulacji numerycznych opracowanych dla sprzężonego sprężysto-sztywnego modelu o siedmiu stopniach swobody. Otrzymane wyniki z reguły potwierdzają, że sposób zamontowania wyposażenia (sztywne lub sprężyste), wraz z warunkami prędkości jazdy, mają wpływ na poziom wibracji w wybranych punktach odniesienia na częstotliwości rezonansowej w symetrycznym trybie zgięciowym. Pokazano także jak masa wyposażenia i stopień tłumienia w systemie jego zawieszenia wpływają na poziom wibracji nadwozia.
Źródło:
Archive of Mechanical Engineering; 2016, LXIII, 1; 145-162
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The transition effect in rail tracks – assessment of transient energy for low frequency vibrations
Autorzy:
Sołkowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/231030.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
strefa przejściowa
efekt przejścia
modelowanie
tor kolejowy
podtorze
właściwości
analiza stanów przejściowych
metoda energii
drgania niskiej częstotliwości
transition zone
transition effect
modelling
railtrack
track foundation
characteristics
transient analysis
energy approach
low frequency vibration
Opis:
The transition effect between different track-foundation systems is examined from the point of view of energy that is produced during the passage of load. Analytical solution is given. A model of beam on elastic foundation with damping is used as the base model. It is developed into a model composed of two parts that represent the track-subgrade system with an abrupt change in mechanical parameters: bending stiffness, foundation stiffness, damping, and mass. Several calculations are carried out including examples of comparative calculations with the Finite Difference Model and the Finite Element Model. Transient rail deflections and energy are determined, which may serve to estimate the rate of track-subgrade deterioration.
Źródło:
Archives of Civil Engineering; 2014, 60, 1; 123-143
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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