Temat: passive control - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Some aspects of vibration control. Part I: Active and passive correction
Autorzy:: Kosowski, K.
Tematy:: harmonic vibrations
passive control
active control; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/259185.pdf Link otwiera się w nowym oknie
Opis:: The paper presents a general approach to mechanical system modification aimed at controlling the steady harmonic vibrations by means of passive and active methods. The relaŹtive decrease of harmonic vibration amplitudes of selected elements of the mechanical system has been chosen as a measure of the quality of the introduced modification. The proposed theoretical method enables to determine the parameters of the system’s dynamic flexibility matrix, which show the most remarkable effect on the dynamic behaviour of the whole system. When active control is considered the method is useful in designing the structure and choosing the parameters of the control system. In certain in cases of self-excited vibration the approach helps examining the elements of the system, most responsible for this kind of excitation.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: An analysis of a piezo-elastic restrictor using a capacitive shunt
Autorzy:: Kekana, M.
Badur, J.
Tematy:: passive control
piezo-elastic
deflection; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1954087.pdf Link otwiera się w nowym oknie
Opis:: The study investigates the control of structural response using collocated piezoelectric elements mounted on both sides of beam. A capacitive shunt is introduced into the circuitry to provide passive control of the beam's configuration. The energy method is used to develop the structure's governing equations. In order to select the appropriate electrostatic relations for the material, i.e. conductor or insulator material, the free charge rearrangement time is used. The effects of the capacitive shunt are introduced into the electrostatic relations using additive decomposition of capacitance. As an application of the model, a piezo-elastic beam restrictor using a capacitive shunt is investigated. Numerical results show that the capacitive shunt can effect passive control of the configuration of the beam.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Hybrid passivity based and fuzzy type-2 controller for chaotic and hyper-chaotic systems
Autorzy:: Serrano, F.
Rossell, J. M.
Tematy:: chaos synchronization
passive control
type-2 fuzzy controller
chaotic system; Pokaż więcej
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:: https://bibliotekanauki.pl/articles/387506.pdf Link otwiera się w nowym oknie
Opis:: In this paper a hybrid passivity based and fuzzy type-2 controller for chaotic and hyper-chaotic systems is presented. The proposed control strategy is an appropriate choice to be implemented for the stabilization of chaotic and hyper-chaotic systems due to the energy considerations of the passivity based controller and the flexibility and capability of the fuzzy type-2 controller to deal with uncertainties. As it is known, chaotic systems are those kinds of systems in which one of their Lyapunov exponents is real positive, and hyperchaotic systems are those kinds of systems in which more than one Lyapunov exponents are real positive. In this article one chaotic Lorentz attractor and one four dimensions hyper-chaotic system are considered to be stabilized with the proposed control strategy. It is proved that both systems are stabilized by the passivity based and fuzzy type-2 controller, in which a control law is designed according to the energy considerations selecting an appropriate storage function to meet the passivity conditions. The fuzzy type-2 controller part is designed in order to behave as a state feedback controller, exploiting the flexibility and the capability to deal with uncertainties. This work begins with the stability analysis of the chaotic Lorentz attractor and a four dimensions hyper-chaotic system. The rest of the paper deals with the design of the proposed control strategy for both systems in order to design an appropria.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Passive control of shock wave applied to helicopter rotor high-speed impulsive noise reduction
Autorzy:: Doerffer, P.
Szulc, O.
Tematy:: shock wave
passive control
perforated wall
transpiration
helicopter rotor in hover
high-speed impulsive noise; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1943208.pdf Link otwiera się w nowym oknie
Opis:: A strong, normal shock wave, terminating a local supersonic area on an airfoil (or a helicopter blade), not only limits the aerodynamic performance, but also becomes a source of High-Speed Impulsive (HSI) noise. The application of a passive control system (a cavity covered by a perforated plate) on a rotor blade should reduce the noise created by the moving shock. This article describes numerical investigations focused on the application of a passive control device on a helicopter blade in high-speed transonic hover conditions to weaken the shock wave – the main source of HSI noise.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: A power shaping based control strategy for dual active full-bridge converter
Autorzy:: Zhang, Yajing
Ma, Hao
Wang, Xiuteng
Shao, Tiancong
Tematy:: Brayton–Moser theory
DAB
dual active full-bridge
DC
direct current microgrids
passive control; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/59111810.pdf Link otwiera się w nowym oknie
Opis:: Dual active full-bridge (DAB) DC–DC converters are widely used in DC microgrids and various fields of power electronics. It has the advantages of high-power density, easy to implement soft switching and bi-directional power transfer capability. Conventional linear controllers have difficulty in meeting the increasing demands for speed and robustness. In this paper, a control strategy based on the Brayton–Moser theory of power shaping is proposed to improve the control strategy of DAB DC–DC converters. The DAB DC–DC converter is modelled and the controller is designed based on the Brayton–Moser power-shaping theory. A simulation of the DAB DC–DC converter is constructed and a comparative analysis is carried out for three control strategies of PI control, passive control and power-shaping Brayton–Moser control under different operating conditions.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Transient Thermal Analysis of 1U Modular Cubesat Based on Passive Thermal Control System
Autorzy:: Kubade, Sunidhi
Kulkarni, Shruti
Dhatrak, Pankaj N.
Tematy:: CubeSat
transient thermal analysis
passive thermal control
thermal strap
MLI; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/59110750.pdf Link otwiera się w nowym oknie
Opis:: Cube Satellites are miniaturized satellites used for space research with a mass of not more than 1.33 kg per unit. They are widely used in space applications because of its low cost of manufacturing and flexibility of applications. Since, they use commercial off-the-shelf components, thermal consideration of internal components of 1-unit cube satellites becomes a necessity. In this paper, transient thermal analysis of a 1-unit cube satellite is conducted to analyze its behavior during the first 29 seconds of orbit insertion from the launch vehicle. Transient thermal analysis yielded a temperature range that exceeded the optimum limit. As a result, to reduce heat dissipation, two main types of thermal management systems for satellites: active control and passive control systems are included. To maintain critical components at their operating temperature, a passive thermal control is implemented. Thermal strap and multi-layer insulation are used to analyze internal components of 1-unit cube satellite. Using graphite fiber thermal strap and aerogel multi-layer insulation for internal components, the 1-unit modular cube satellite is found to be more suitable under low earth orbit conditions.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Numerical loss analysis in a compressor cascade with leading edge tubercles
Autorzy:: Zheng, T.
Qiang, X.-Q.
Teng, J.-F.
Teng, J.-Z.
Tematy:: compressor cascade
flow separation
passive flow control
leading edge tubercles
streamwise vortices
loss analysis; Pokaż więcej
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:: https://bibliotekanauki.pl/articles/280966.pdf Link otwiera się w nowym oknie
Opis:: A numerical analysis of loss has been carried out to explore the loss mechanism of leading edge tubercles in a high speed compressor cascade. Taking the lead from flippers of the humpback whale, tubercles are passive structures of a blade for flow control. Evaluation of the overall performance in terms of entropy increase shows that the loss reduction is achieved both at high negative and high positive incidence angles, while a rise in the loss is obtained near the design point. And a smaller wave number as well as a smaller amplitude results in lower additional losses at the design point. Spanwise and streamwise distributions of pitchwise-averaged entropy increase combined with flow details have been presented to survey the loss development and, subsequently, to interpret the loss mechanism. The tubercle geometry results in the deflection flow and the consequent spanwise pressure gradient. This pressure gradient induces formation of counter-rotating streamwise vortices, transports away the low-momentum fluid near wall from crests towards troughs and leads to local high loss regions behind troughs as well as loss reduction behind the crests in comparison to the baseline. The interaction between these vortices and flow separation by momentum transfer leads to separation delay and the consequent loss reduction at the outlet.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Pasywna stabilizacja rozkładu napięć w obwodzie pośredniczącym falownika trójpoziomowego NPC
Passive control of the DC-link midpoint voltage in the three-level NPC inverter
Autorzy:: Szczepankowski, P.
Nieznański, J.
Tematy:: falownik trójpoziomowy
modulacja szerokości impulsów
pasywna stabilizacja napięcia punktu środkowego
three-level NPC inverter
pulse width modulation (PWM)
passive control of the DC-link midpoint voltage; Pokaż więcej
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Powiązania:: https://bibliotekanauki.pl/articles/154083.pdf Link otwiera się w nowym oknie
Opis:: Przedstawiono wyniki badań dotyczące pasywnej stabilizacji rozkładu napięć w obwodzie pośredniczącym falownika trójpoziomowego NPC wskazujące na dobre uwarunkowania tej metody i możliwość jej wykorzystania w zastosowaniach praktycznych. Odpowiednio skonstruowana stabilizacja pasywna zapewnia stateczną pracę z podtrzymywaniem równowagi napięć i powrót napięcia niezrównoważenia do zerowej wartości średniej po ewentualnym zaburzeniu tej równowagi.
The paper presents and discusses some test results pertaining to the passive control of the DC-link midpoint voltage in the three-level NPC inverter. The results indicate that the method is well-behaved, insuring stable operation with balanced voltages across both capacitors in the DC link, convergence to a voltage balance after possible disturbances and low sensitivity to asymmetries in the inverter load.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Numerical investigation of root canal irrigation adopting innovative needles with dimple and protrusion
Autorzy:: Li, P.
Zhang, D.
Xie, Y.
Lan, J.
Tematy:: dimple
protrusion
innovative needles
numerical simulation
passive flow control methods
root canal irrigation
wychylenie zębów
symulacja komputerowa
kanał zębowy; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/307257.pdf Link otwiera się w nowym oknie
Opis:: As important passive flow control methods, dimples and protrusions have been successfully implemented via geometric modifications to manipulate flow fields to get a desired flow parameters enhancement. In this research, two novel needles were proposed based on a prototype by means of the dimple and protrusion, and flow patterns within a root canal during final irrigation with these needles were numerically investigated. The calculation cases consistent with the clinically realistic irrigant flow rates, which are 0.02, 0.16 and 0.26 mL s–1 are marked as case A, B and C, respectively. The characteristic parameters to estimate irrigation efficiency, such as shearing effect, mean apical pressure, irrigation replacement and fluid agitation, were compared and the optimal geometry in every calculation case was obtained. As shown from the results, flow rates and needle geometries were the causes of irrigation parameters variations. The sum of shear stress, irrigation replacement and fluid agitation were equal in the low flow rate case A, however, the needle with a protrusion on its tip had advantages in the three irrigation characteristic parameters above in calculation case B, and the needle with a dimple on its tip had advantages in calculation case C. Furthermore, the needles proposed did not give rise to the risk of irrigant extrusion. These needles can be better choices at larger flow rates. Therefore, needle geometry optimizations utilizing passive flow control methods are worthy to be investigated in the root canal irrigation enhancement.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Comparing the efficiency of different structural skeleton for base isolated domes
Autorzy:: Casciati, Sara
Tematy:: base isolation
design requirements
dome
isolation device
passive structural control
wymagania projektowe
kopuła
urządzenie izolujące
izolacja sejsmiczna
kontrola strukturalna pasywna; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/27311406.pdf Link otwiera się w nowym oknie
Opis:: The structural concept of the dome dates back to the Pantheon in Rome. It is used as the cover of many churches and mosques all around the world. Light solutions, with a well-visible dome-shaped truss skeleton, are often preferred in modern architecture. Base isolation techniques can be adopted to mitigate the seismic effects. This paper aims to investigate the efficiency of different designs for the truss skeleton. To solve the problem, one has to assign the constraints, the materials and the geometry of the dome, its supporting structure and the isolation devices (number, locations, and type). The screening of the effects of different scheme assumptions on structural behaviour provides a better insight into the problem.
Dostawca treści:: Biblioteka Nauki

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