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Wyszukujesz frazę "flexible structures" wg kryterium: Temat


Tytuł:
Influence of orthogonal methods on design process of vibration control system for cantilever beam with non-collocated piezo-elements
Autorzy:
Koszewnik, Andrzej
Tematy:
vibration control systems
flexible structures
cantilever beam
Pokaż więcej
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:
https://bibliotekanauki.pl/chapters/32083872.pdf  Link otwiera się w nowym oknie
Opis:
In this paper, we consider the influence of the model reduction on the dynamics of the real closed-loop system. A simple cantilever beam is the object of consideration since we are able to formulate the exact analytical model of such structure. As a result of reduction, the model with low frequency resonances is usually separated from the high frequency dynamics because high frequency part of the model is naturally strong damped. In order to estimate dynamical system for control purposes in the paper, we applied a few orthogonal methods such as: modal and Schur decompositions. As it is shown, all methods well calculate resonances frequencies but generate different antiresonances frequencies. In the vibration control systems, the antiresonances play essential role. They influence the stability and dynamics of the closed-loop systems. The controllers designed for different reduced models were applied to real full plant. Dynamics behavior of the closed-loop systems with such controllers were analyzed and compared. The theoretical considerations were confirmed by experimental investigations. In conclusion, we should carefully choose model reduction methods in the design process of the vibration control system.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monitoring of Soil-steel Structures During Construction
Autorzy:
Mońka, Michał
Tomala, Piotr
Machelski, Czesław
Wydawca:
BGJ Consulting
Cytata wydawnicza:
Machelski, C., Mońka, M., Tomala, P. (2019). Monitoring of Soil-steel Structures During Construction. Journal of Current Construction Issues. CIVIL ENGINEERING PRESENT PROBLEMS, INNOVATIVE SOLUTIONS - Circular Economy in Construction Sector : 159-168.
Opis:
A unique feature of soil-steel structures, unlike classical bridges, for example vaulted ones, is the very large effect of backfill and road superstructure on the bearing capacity of the bridge. In the model of a buried structures made of corrugated steel plates, two structural subsystems are distinguished: a flexible arch shell and a soil backfill with road superstructure. The interaction between these subsystems is modelled as a contact layer, i.e. forces with a normal and tangent direction to the surface of the steel shell. It is a static condition for the compatibility of mutual interactions between soil and coating. Between the sub-systems, slip is allowed, i.e. the difference of displacements. The paper presents the structure safety assessment algorithm based on the shell deformation determined on the basis of deflection measurement and change of curvature in the shell crown point. The construction phase of the structure is analysed and a also the symmetrical deformation is assumed during the backfill material placement. Usually, during the bridge construction the forces in the steel shell are several times greater than those arising from operational loads. For this reason, the results of analyses given in the paper are also important as the basis for calculation and behaviour of the soil during live loads.
Dostawca treści:
Repozytorium Centrum Otwartej Nauki
Artykuł
Tytuł:
Adaptive stabilization of undamped flexible structures
Autorzy:
Kobayashi, T.
Tematy:
kompensator równoległy
stabilizacja adaptacyjna
adaptive stabilization
parallel compensators
undamped flexible structures
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Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Powiązania:
https://bibliotekanauki.pl/articles/206868.pdf  Link otwiera się w nowym oknie
Opis:
In this paper non-identifier-based adaptive stabilization of undamped flexible structures is considered in the case of collocated input and output operators. The systems have poles and zeros on the imaginary axis. In the case where velocity feedback is available, the adaptive stabilizer is constructed by an adaptive PD-controller (proportional plus derivative controller). In the case where only position feedback is available, the adaptive stabilizer is constructed by an adaptive P-controller for the augmented system which consists of the controlled system and a parallel compensator. Numerical examples are given to illustrate the effectiveness of the proposed controllers.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Controllability-oriented placement of actuators for active noise-vibration control of rectangular plates using a memetic algorithm
Autorzy:
Wrona, S.
Pawełczyk, M.
Tematy:
active control
flexible structures
actuators placement
controllability Gramian
evolutionary algorithm
memetic algorithm
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/176577.pdf  Link otwiera się w nowym oknie
Opis:
For successful active control with a vibrating plate it is essential to appropriately place actuators. One of the most important criteria is to make the system controllable, so any control objectives can be achieved. In this paper the controllability-oriented placement of actuators is undertaken. First, a theoretical model of a fully clamped rectangular plate is obtained. Optimization criterion based on maximization of controllability of the system is developed. The memetic algorithm is used to find the optimal solution. Obtained results are compared with those obtained by the evolutionary algorithm. The configuration is also validated experimentally.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Durability of flexible steel corrugated shell structures - theory and practice
Autorzy:
Wysokowski, A.
Tematy:
flexible steel structures
durability
fatigue
corrosion
service life
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Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Powiązania:
https://bibliotekanauki.pl/articles/383408.pdf  Link otwiera się w nowym oknie
Opis:
The technical issues described in this paper concern the durability aspects of buried flexible steel structures. It is well known that due to the nature of the bridge loads including buried flexible steel structures, they are particularly exposed to fatigue. Fatigue of steel structures - in this case corrugated steel plates - is closely related to such important parameters as safety and durability, and has direct impact on the service life of these structures. As these issues are very important, they are often analyzed by many research centers, with the present author contributing to the work of many of them. Fatigue reveals itself in the critical phase as fatigue cracks in structural steel, or in the joints. In such critical cases this leads to the exclusion of objects from the service. The fatigue of soil structure around the steel corrugated shell in the structures under analysis should also be taken into account. Fatigue in steel structures intensified by the occurrence of corrosion due to the operating conditions of the structures (negative environmental impact of water) is widespread. According to the author, proper construction of buried flexible steel structures and their maintenance undoubtedly increase the safety of users and extend the service life. At the end on the paper the author describes one of the methods of increasing the durability of shell structures by reinforcing the soil using a geotextile geomembrane.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Feedforward Control of a Light-Weight Device Casing for Active Noise Reduction
Autorzy:
Wrona, S.
Pawelczyk, M.
Tematy:
active control
flexible structures
active noise control
active vibration control
active structural acoustic control
active casing
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/177744.pdf  Link otwiera się w nowym oknie
Opis:
It is possible to enhance acoustic isolation of the device from the environment by appropriately controlling vibration of a device casing. Sound insulation efficiency of this technique for a rigid casing was confirmed by the authors in previous publications. In this paper, a light-weight casing is investigated, where vibrational couplings between walls are much greater due to lack of a rigid frame. A laboratory setup is described in details. The influence of the cross-paths on successful global noise reduction is considered. Multiple vibration actuators are installed on each of the casing walls. An adaptive control strategy based on the Least Mean Square (LMS) algorithm is used to update control filter parameters. Obtained results are reported, discussed, and conclusions for future research are drawn.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Foundation of flexible steel structures - developmental trends
Autorzy:
Wysokowski, A.
Mońka, M.
Howis, J.
Tematy:
buried flexible steel structures
foundation
developmental trends
flexible foundations
laboratory tests
optimization
Pokaż więcej
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Powiązania:
https://bibliotekanauki.pl/articles/383436.pdf  Link otwiera się w nowym oknie
Opis:
The technical issues described in the paper concern aspects of foundations of buried flexible steel structures. The foundations of these structures are most frequently made as traditional “rigid” structures (which is related to their massiveness - most commonly reinforced concrete), or in the form of properly profiled soil foundations (depending on the shape of the coating). Comparison of the two issues of “vulnerability”, i.e. the bearing structure and the ’’rigidity” of foundations, is the main motivation to carry out testing and conduct an analysis in this area. The problems are discussed in the paper in the context of new developments in the field of “flexible” foundations of the structures in question. Further development analyses are currently in progress , which will be practically implemented in the form of appropriate guidelines. In the authors' opinion, this will help to optimize the design of the in which the foundation of these structures.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Work analysis of soil-steel structure in the construction phase illustrated with SuperCor SC-57S
Analiza pracy konstrukcji gruntowo-powłokowej w fazie wykonywania na przykładzie konstrukcji SuperCor SC-57S
Autorzy:
Kosno, Ł.
Tematy:
oil-steel structure
corrugated steel plate
flexible structures
SuperCor structures
konstrukcja gruntowo-powłokowa
falista blacha stalowa
struktury elastyczne
konstrukcja SuperCor
Pokaż więcej
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Powiązania:
https://bibliotekanauki.pl/articles/402112.pdf  Link otwiera się w nowym oknie
Opis:
This the paper aims to present the results of studies of the flexible SuperCor SC-57S structure built by Polish manufacturer “ViaCon Polska Sp. z o.o.” to determine maximum values of displacement and internal forces that occur in the structure during its construction. The finite element method was used to develop a numerical model of the structure whose behaviour was then simulated. The conclusions based on the values of measured displacements and internal forces may be helpful in understanding the behaviour of flexible steel and soil structures.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Examination of remaining zinc coating on old corrugated steel culverts under railway
Autorzy:
Hansing, L.
Cederqvist, S.
Tematy:
remaining zinc coating
flexible structures
old corrugated steel culverts
life time of zinc coating
atmospheric corrosion
mass loss
thickness reduction
Pokaż więcej
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Powiązania:
https://bibliotekanauki.pl/articles/383930.pdf  Link otwiera się w nowym oknie
Opis:
In this paper the authors present measurements of the zinc coating thickness performed on old corrugated steel culverts under railway in Sweden. The measurements were performed in the summer of 2015. The object of the study is to have an indication on how hot dip galvanized corrugated steel culverts withstand real conditions. This information forms an important basis for the decision on possible life time expectancies for those structures.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of an memetic algorithm to placement of sensors for active noise-vibration control
Zastosowanie algorytmu memetycznego do rozmieszczenia czujników w celu aktywnej redukcji drgań i hałasu
Autorzy:
Wrona, S.
Pawełczyk, M.
Tematy:
active control
flexible structures
sensor placement
observability Gramian
genetic algorithm
memetic algorithm
aktywna redukcja drgań
aktywna redukcja hałasu
elastyczne struktury
rozmieszczenie czujników
macierz Grama obserwowalności
algorytm genetyczny
algorytm memetyczny
Pokaż więcej
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:
https://bibliotekanauki.pl/articles/973156.pdf  Link otwiera się w nowym oknie
Opis:
For successful active control of a vibrating structure it is essential to appropriately place sensors. One of the most important criteria is to make the system observable, so any control objectives can be achieved. In this paper the observability-oriented placement of sensors is undertaken. First, a theoretical model of a fully clamped plate is presented. Optimization criterion based on maximization of observability of the system is developed. A memetic algorithm is used to find the optimal solution. Obtained results are compared with those obtained by the genetic algorithm.The configuration is also validated experimentally.
W celu skutecznej aktywnej redukcji drgań i hałasu konstrukcji konieczne jest odpowiednie rozmieszczenie czujników. Jednym z najważniejszych kryteriów jest uczynienie obiektu obserwowalnym, aby jakiekolwiek cele sterowania mogły zostać osiągnięte.W pracy podjęte zostało zagadnienie rozmieszczenia czujników w oparciu o analizę obserwowalności. Zaprezentowany został model teoretyczny płyty o brzegach całkowicie utwierdzonych. Wyprowadzone zostało kryterium optymalizacji w oparciu o maksymalizacje miary obserwowalności. Do znalezienia rozwiązania optymalnego zastosowano algorytm memetyczny. Otrzymane wyniki zostały porównane z wynikami uzyskanymi za pomocą algorytmu genetycznego. Wyznaczone rozmieszczenie czujników zostało zweryfikowane eksperymentalnie.
Dostawca treści:
Biblioteka Nauki
Artykuł

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