Temat: structural control - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Passive-active noise control of an acoustic duct
Pasywno-aktywne metody kontroli hałasu w przewodzie akustycznym
Autorzy:: Tiseo, B.
Concilio, A.
Tematy:: acoustic structural control
damping noise control
feedback; Pokaż więcej
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:: https://bibliotekanauki.pl/articles/281856.pdf Link otwiera się w nowym oknie
Opis:: In the recent years, noise control has become a significant factor in the design of automotive and aircraft industries. In general, methods of the passive noise control are practical and most effective at mid and high frequencies. On the other hand, active noise control techniques are more efficient at the low frequency range. Combined solutions seem to be the most appropriate key to cover the whole frequency range of frequencies. In the present study, a description of simulations for both feedback structural and acoustical structural control strategies are illustrated in order to maximize the damping within an acoustic duct by applying a passive foam layer bonded to an “active” surface.
W ostatnich latach problem sterowania poziomem hałasu stał się szczególnie znaczący w projektowaniu na potrzeby przemysłu samochodowego i lotniczego. Jako ogólną zasadę można przyjąć, że pasywne metody redukcji hałasu są efektywne dla średnich i wysokich częstości dźwięku, podczas gdy metody aktywne dobrze się sprawdzają dla częstości niskich. Rozwiązanie oparte na kombinacji tych metod stanowi naturalny i najbardziej skuteczny sposób ograniczania hałasu w całym przedziale częstości. W pracy przedstawiono opis strategii sterowania poziomem hałasu bazującym na strukturalnym i akustycznym sprzężeniu zwrotnym, celującym w maksymalizację tłumienia wewnątrz przewodu akustycznego, na którego „aktywną” powierzchnię naniesiono warstwę pasywnej pianki.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Sound Transmission Through a Thin Plate with Shaped Frequency Response
Autorzy:: Wrona, Stanislaw
Mazur, Krzysztof
Rzepecki, Jaroslaw
Chraponska, Anna
Pawelczyk, Marek
Tematy:: structural control
frequency response shaping
vibrating plate
optimisation
modelling; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/177996.pdf Link otwiera się w nowym oknie
Opis:: Thin plates, in the form of individual panels or whole device casings, often separate the noise source from its recipients. It would be very desirable if the panels could effectively block the sound transmission preventing noise from further propagation. This is especially challenging to achieve at low frequencies. A promising approach, intensively developed in the recent years, is to employ active control methods by adding sensors and actuators, and running a control algorithm. However, if the noise is narrow-band, an alternative passive solution originally developed by the authors can be applied. It is based on appropriately located passive elements which can be used to alter the frequency response of the vibrating structure thus improving its sound insulation properties. Such an approach is referred to as the frequency response shaping method. The purpose of this paper is to further develop this method and apply it to a device casing panel. The efficiency of the method is evaluated by simulation and real experiments. Appropriate cost functions and mathematical models are formulated and used to optimise the arrangement of passive elements mounted to the plate, enhancing its sound insulation properties at the given frequency range. The results are reported, and advantages and limits of the method are pointed out and discussed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: The structural control of a landslide development and functioning of a lake geoecosystem in the catchment area of the Hucianka Stream (the Outer Carpathians, Beskid Niski)
Autorzy:: Zatorski, Michał
Buczek, Krzysztof
Franczak, Paweł
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 4.

Tytuł:: Dynamic behavior of steel frames with tuned mass dampers
Autorzy:: Jouneghani, K. T.
Hosseini, M.
Rohanimanesh, M. S.
Dehkordi, M. R.
Tematy:: earthquake
Tuned Mass Dampers
vibration control
dynamic behaviour
steel frames
structural control; Pokaż więcej
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Powiązania:: https://bibliotekanauki.pl/articles/103041.pdf Link otwiera się w nowym oknie
Opis:: In this paper, the application of tuned mass damper in improving the response of structures is considered. At first, three frames of 3, 9 and 20 stories are evaluated in which time history analysis is done according to El – Straw earthquake. The maximum reduction of among the three mentioned frames belongs to a 20-stories structure in which the rate of story displacement reduction is between 25 to 45%, and this indicates that by increasing the height of the structure, the performance of tuned mass damper improved. In the second part, the effect of semi-active tuned mass damper is studied on a 10-stories frame. Studies showed that using a tuned mass damper system with viscous damper with controller force decreases the average of maximum displacement of roof story down to 39.9 % and this amount of reduction is 22.8% for semi-active tuned mass damper. Finally, the performance of tuned Single and multiple mass Damper is evaluated on a 20-stories frame, and the results show that single and multiple dampers decrease structures ‘responses and the performance of tuned multiple dampers depends on the mass and frequency ratio and also concluded that the performance of tuned multiple mass dampers is reduced by transition to middle of the structure stories.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: The use of synthesis methods in position optimisation and selection of tuned mass damper (TMD) parameters for systems with many degrees of freedom
Autorzy:: Dymarek, Andrzej
Dzitowski, Tomasz
Tematy:: structural control system
vibration
simple fractions
synthesis
rational functions
dynamic characteristics; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/1409049.pdf Link otwiera się w nowym oknie
Opis:: The paper formulates and formalises a method for selecting parameters of the tuned mass damper (TMD) for primary systems with many degrees of freedom. The method presented uses the properties of positive rational functions, in particular their decomposition, into simple fractions and continued fractions, which is used in the mixed method of synthesis of vibrating mechanical systems. In order to formulate a method of tuning a TMD, the paper discusses the basic properties of positive rational functions. The main assumptions of the mixed synthesis method is presented, based on which the general method of determining TMD parameters in the case of systems with many degrees of freedom was formulated. It has been shown that a tuned mass damper suppresses the desired resonance zone regardless of where the excitation force is applied. The advantages of the formulated method include the fact of reducing several forms of the object’s free vibration by attaching an additional system with the number of degrees of freedom corresponding to the number of resonant frequencies reduced. In addition, the tuned mass damper determined in the case of excitation force applied at a single point can be attached to any element of the inertial primary system without affecting the reduction conditions in this way. It results directly from the methodology formalised in the paper. As part of the paper, numerical calculations were performed regarding the tuning of the TMD to the first form of free vibration of a system with 3 degrees of freedom. The parameters determined were subjected to analysis and verification of the correctness of the calculations carried out. For the considered case of a system with 3 degrees of freedom together with a TMD, time responses of displacement, from each floor, were generated to excitation induced by a harmonic force equal to the first form of vibration of the basic system. In addition, in the case of the parameters obtained, the response of the inertial element system to which the TMD was attached to random white noise excitation was determined.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Geological control on the Osława River meander at Duszatyn, Western Bieszczady Mountains, Polish Outer Carpathians
Autorzy:: Margielewski, W.
Tematy:: neotectonics
structural control
Quaternary alluvium
Osława River
Western Bieszczady Mountains
Polish Outer Carpathians; Pokaż więcej
Wydawca:: Polskie Towarzystwo Geologiczne
Powiązania:: https://bibliotekanauki.pl/articles/191585.pdf Link otwiera się w nowym oknie
Opis:: At Duszatyn village (Western Bieszczady Mts.), the Osława River forms an unique meander loop which is not typical for the mountainous area. Detailed analysis has shown that this landform was created due to the evolution of two left-hand tributaries of the Osława River during the formation of its regressive water-gap. These processes were determined by mass movements which have strongly stimulated the fluvial system. The origin of the Osława River meander was largely controlled by lithological differences in rock resistance, orientation of the joint pattern, as well as the presence of bordering oblique and thrust faults which have had a bearing on the diversified neotectonic uplift of the area.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: The structural control of the Mroczna Cave development on the slopes of Mt Kornuty (the Flysch Carpathians, Beskid Niski Mts)
Autorzy:: Zatorski, Michał
Opis:: The Mroczna Cave is one of the longest caves in the Beskid Niski Mts., located on the south-western slopes of Mt Kornuty, along the main scarp of the landslide. According to the geomechanical criterion, it is dilation cave, where extension has played a major role. Morphotectonic analysis indicates that the main gravitational movement was of a toppling nature but there were also rotation around the vertical axis as well as a backward rotation. The relatively large cave depth (15.5 m) and its shape (cross-section of its passages) indicate that it was formed along a new gravitational cutting surface of the rock massif, associated with joint sets.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 8.

Tytuł:: The structural control of the Mroczna Cave development on the slopes of Mt Kornuty (the Flysch Carpathians, Beskid Niski Mts)
Autorzy:: Zatorski, M.
Tematy:: mass movements
flysch Carpathians
crevice-type cave
structural control
anisotropic rock massif; Pokaż więcej
Wydawca:: Stowarzyszenie Geomorfologów Polskich
Powiązania:: https://bibliotekanauki.pl/articles/295108.pdf Link otwiera się w nowym oknie
Opis:: The Mroczna Cave is one of the longest caves in the Beskid Niski Mts., located on the south-western slopes of Mt Kornuty, along the main scarp of the landslide. According to the geomechanical criterion, it is dilation cave, where extension has played a major role. Morphotectonic analysis indicates that the main gravitational movement was of a toppling nature but there were also rotation around the vertical axis as well as a backward rotation. The relatively large cave depth (15.5 m) and its shape (cross-section of its passages) indicate that it was formed along a new gravitational cutting surface of the rock massif, associated with joint sets.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Weak compactness in the space of operator valued measures $M_ba(Σ,(X,Y))$ and its applications
Autorzy:: Ahmed, N.
Tematy:: space of operator valued measures
weak compactness
semigroups of bounded linear operators
optimal structural control; Pokaż więcej
Wydawca:: Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Powiązania:: https://bibliotekanauki.pl/articles/729361.pdf Link otwiera się w nowym oknie
Opis:: In this note we present necessary and sufficient conditions characterizing conditionally weakly compact sets in the space of (bounded linear) operator valued measures $M_{ba}(Σ,(X,Y))$. This generalizes a recent result of the author characterizing conditionally weakly compact subsets of the space of nuclear operator valued measures $M_{ba}(Σ,₁(X,Y))$. This result has interesting applications in optimization and control theory as illustrated by several examples.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Active noise control with a single nonlinear control filter for a vibrating plate with multiple actuators
Autorzy:: Mazur, K.
Pawełczyk, M.
Tematy:: active noise-vibration control
active structural acoustic control
adaptive control
nonlinear control; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/176906.pdf Link otwiera się w nowym oknie
Opis:: Vibrating plates can be used in Active Noise Control (ANC) applications as active barriers or as secondary sources replacing classical loudspeakers. The system with vibrating plates, especially when nonlinear MFC actuators are used, is nonlinear. The nonlinearity in the system reduces performance of classical feedforward ANC with linear control filters systems, because they cannot cope with harmonics generated by the nonlinearity. The performance of the ANC system can be improved by using nonlinear control filters, such as Artificial Neural Networks or Volterra filters. However, when multiple actuators are mounted on a single plate, which is a common practice to provide effective control of more vibration modes, each actuator should be driven by a dedicated nonlinear control filter. This significantly increases computational complexity of the control algorithm, because adaptation of nonlinear control filters is much more computationally demanding than adaptation of linear FIR filters. This paper presents an ANC system with multiple actuators, which are driven with a single nonlinear filter. To avoid destructive interference of vibrations generated by different actuators the control signal is filtered by appropriate separate linear filters. The control system is experimentally verified and obtained results are reported.
Dostawca treści:: Biblioteka Nauki

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