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Wyszukujesz frazę "longitudinal oscillations" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Control effectiveness comparison of wheel loaders longitudinal vibrations by means of passive and active vibration stabilisers
Autorzy:
Kosiara, A.
Powiązania:
https://bibliotekanauki.pl/articles/244576.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
wheel loader
longitudinal oscillations
active stabiliser
passive stabiliser
state controller synthesis
Opis:
When wheel loaders move with velocity higher than 10 km/h, they are subject to intense longitudinal vibrations. These vibrations are experienced particularly unpleasantly by an operator. Passive vibration stabilisers are used for controlling their intensity. They make outrigger's support more flexible so that outrigger's vibrations counteract the wheel loader's longitudinal oscillations when moving. Unfortunately, the effectiveness of passive stabilisers is insufficient and at present more effective alternative means are sought. One of the solutions for angular longitudinal vibrations includes the replacement of passive stabilisers with active stabilisers. Nevertheless, the possibility of active stabilisers’ use in minimising longitudinal vibrations requires a scientific assessment. Hence, this paper, meeting the needs, includes calculations, which allow for comparing the effectiveness of active and passive stabilisers in minimising the vibrations of a typical wheel loader. Active stabilisers, which are the subject of the study, worked based on state controller, whose synthesis was carried out on the basis of optimal control linear theory with square quality indicator. The calculations were conducted on linear models under stochastic road excitations. Stochastic excitations were defined by means of power spectral density of road's unevenness. Active stabiliser's effectiveness was analysed, both for a loader moving with an empty bucket, and for a loader transporting a 3-tonne load. In order to facilitate the analysis of the results obtained, vibrations minimising quality indicator was introduced, defined as a root of a vehicle longitudinal deflections power.
Źródło:
Journal of KONES; 2011, 18, 1; 287-294
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The impact of selected structural parameters in unsprung industrial vehicles on their longitudinal oscillations
Autorzy:
Kosiara, A.
Powiązania:
https://bibliotekanauki.pl/articles/950131.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
oscillations
modelling
industrial vehicles
longitudinal dynamics of industrial vehicles
spectral transmittance
Opis:
The study presents an analysis of the impact of selected structural parameters in umprung industrial vehicles on their longitudinal oscillations. It was conducted on the basis of a simplified, linear, two-dimensional model in the form of a parametric spectral transmittance. Transfer function was developed on a number of simplifying assumptions, of which the more significant ones include: the assumption of small oscillations, the assumption that wheełs are in constant contact with the ground, lack of the impact of the horizontal components of the input on the vehicle dynamics, lack of the impact of the wheel slip and the drive system on the vehicle dynamics, single-point contact of the wheels with the ground etc. The qualitative correctness of the obtained results was partly verified by means of computations using a more complex simulation model of a vehicle by means of the MSC.Adams system. The conducted analyses demonstrate that structural parameters such as the moment of inertia and the value of the tir e damping have a crucial impact on the intensity of longitudinal oscillations in unsprung industrial vehicles. The impact of the oscillation coupling coefficient and the mass is significantly smaller.
Źródło:
Journal of KONES; 2009, 16, 1; 273-280
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analysis of phugoid oscillations of unmanned flying wing
Autorzy:
Mioduska, P.
Powiązania:
https://bibliotekanauki.pl/articles/242816.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
UAV
flying wing
longitudinal stability
phugoid oscillations
Opis:
The flying wing configuration has been considered by airplane designers for more than one hundred years. Tailless aircraft have been inspired by nature and its solutions. In present times, this configuration is used to design Unmanned Aerial Vehicle (UAV). This type of plane could serve personal, military and research purposes. The flying wing is characterized by large amount of payload space, smaller wetted area than conventional airplane and stealth capability. This makes, that it is widely applicable in rescue operations, geodetic and cartographic research, monitoring of natural resources, taking pictures or videos. Despite all the merits of tailless plane, it also has its downsides. The main problem of this type of aircraft is longitudinal stability. A conventional airplane can compensate the pitch moment of the wing with its horizontal tail but a flying wing is tailless. A slow decay of oscillations amplitude is the problem, which can be solved by active control or proper aerodynamic design. A combination of geometric characteristic such as sweep, taper, twist and location of vertical stabilizers along span, can lead to stable flying wing. In this article, the results of phugoid oscillations analysis of unmanned flying wing are presented. Research platform was X8-2, popular flying wing UAV, designed for First Person View (FPV) method to control the vehicle. The calculations were performed using 3D panel method. On the basis of calculations for three versions of the model aircraft, the dynamic characteristics were created. The analysis of longitudinal stability undertaken here has indicated propriety of applied changes in geometry.
Źródło:
Journal of KONES; 2016, 23, 2; 247-254
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MHD flow of longitudinal and torsional oscillations of a circular cylinder with suction in a couple stress fluid
Autorzy:
Nagaraju, G.
Ramana Marthy, J. V.
Powiązania:
https://bibliotekanauki.pl/articles/955274.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
pole magnetyczne
liczba Reynoldsa
współczynnik lepkości
longitudinal and torsional oscillations
drag
suction
radial magnetic field
Opis:
In this paper, we consider the flow an incompressible electrically conducting couple stress fluid generated by performing longitudinal and torsional oscillations of a porous circular cylinder subjected to constant suction/injection at the surface of the cylinder and in the presence of a radial magnetic field. A finite difference method is proposed to analyze the velocity components, in an infinite expansion of a couple stress fluid under vanishing couple stresses on the boundary. The effects of the magnetic parameter, couple stress parameter, Reynolds number, the ratio of couple stress viscosities parameter and suction parameter on velocity components and drag are discussed and shown graphically.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 4; 1099-1114
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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