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1
Content available On the problem of vibration protection of rotor systems with elastic adaptive elements of quasi-zero stiffness
Klitnoi Volodymyr, Gaydamaka Anatoliy
Diagnostyka
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2020
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Vol. 21, No. 2
69--75
EN
The analysis of scientific publications for rotor systems on the elastic supports made it possible to develop a basic version of the design scheme of active elastic support with controlled quasi-zero stiffness based on adaptive piezoceramic elements. The main components of the mathematical model of the functioning of active elastic supports with controlled quasi-zero stiffness based on adaptive piezoceramic elements are substantiated, which will help create the foundations of a theory for solving the problem of effective vibration protection. Numerical results show the possibility of effective applying of the proposed solution to the problem of rotor vibration damping.
2
Content available Buckling of stepped beams resting on an elastic foundation
Kuliński K., Przybylski J.
Journal of Applied Mathematics and Computational Mechanics
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2015
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Vol. 14, nr 4
115--126
EN
The influence of structural parameters of a stepped beam with two ends fixed and resting on Winkler foundation on its buckling critical force has been discussed in this paper. The structure inhomogeneity results from two piezoceramic plates perfectly bonded at the top and bottom surface of the beam. For the performed analysis five different supports of beam ends which prevent longitudinal displacements have been adopted. Numerical analysis has been divided into two parts. The first part concerns the influence of the system geometry on its critical force, whereas in the second part, a modification of the buckling load resulting from the electric field applied to the piezosegment has been investigated.
3
Content available Smart materials as modern engineering substances
Ćwikła A.
Advances in Science and Technology. Research Journal
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2013
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Vol. 7, nr 17
66-72
EN
The article presents the type and use of intelligent materials in aviation and medicine. Their basic features and properties have been discussed. Moreover, the authors quote examples of different uses of intelligent materials, both the existing ones and those in design and development stages. Their use is claimed to be increasing the efficiency and reliability of processes and equipment as well as facilitates the development of new mechanisms.
4
Content available remote Analogies between Shunted Piezoceramics and Mechanical Damping Elements
Neubauer M.
Machine Dynamics Problems
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2009
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Vol. 33, No. 2
79-91
EN
Piezoelectric shunt damping is an emerging field of research. In this technique the electrodes of a piezoceramics are connected to an electrical shunt. Due to the piezoelectric effect, some part of the kinetic energy of the mechanical host structure is converted into electrical energy. The electrical network is designed with the aim to maximize the energy dissipation, which yields a damping effect for the mechanical system. Various electrical shunts like inductance-resistance networks, negative capacitances and switching networks are commonly used for this purpose. In this paper, the effective damping performances of piezoelectric shunt damping with various electrical networks are evaluated. A comparison with viscous damping and dry friction demonstrates the analogies with mechanical damping elements.
5
Content available Sound insulation analysis of plates with piezoceramic elements
Kozupa M., Batko W., Pietrzko S.
Mechanics / AGH University of Science and Technology
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2007
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Vol. 26, no. 4
169-173
EN
This paper represents general idea research to the possibilities of increasing sound insulation of plates by active control it’s vibration through piezoceramic elements placed on the plane. In the preliminary research a rectangular plate 455x560 mm made of steal was analyzed. Sound insulation measurement was executed on a specialized enclosure in reverberation chamber. A PZT piezoceramic was proposed to control vibration of the plate.
PL
Praca przedstawia ogólną koncepcję badań dotyczących analizy możliwości zwiększenia dźwiękoizolacyjności przegród poprzez aktywne sterowanie ich drganiami za pomocą elementów piezolektrycznych rozmieszczonych na ich powierzchni. We wstępnych badaniach analizowano zachowania przegrody w postaci płyty prostokątnej o wymiarach 455 x 560 mm, wykonanej z blachy stalowej. Pomiary dźwiękoizolacyjności wykonano na specjalizowanym stanowisku w komorze pogłosowej. Do sterowania drganiami przegrody zaproponowano elementy piezoceramiczne PZT-4D.
6
Content available remote Penny-shaped crack in a piezoceramic cylinder under Mode I loading
Narita F., Lin S., Shindo Y.
Archives of Mechanics
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2003
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Vol. 55, nr 3
275-304
EN
The electroelastic response of a penny-shaped crack in a piezoelectric cylinder of finite radius is investigated in this study. Fourier and Hankel transforms are used to reduce the problem to the solution of a pair of dual integral equations. They are then reduced to a Fredholm integral equation of the second kind. Numerical values of the stress intensity factor, energy release rate and energy density factor for piezoelectric ceramics are obtained to show the influence of applied electrical loads.
7
Zależność temperaturowej stabilności częstotliwości rezonansowej od stopnia kowalentności wiązań B-O w piezoceramice typu PZT
Surowiak Z., Gavrilyachenko S. V., Kupriyanov M.F., Bochenek D.
Archiwum Nauki o Materiałach
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2000
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T. 21, nr 3-4
177-188
PL
Wykazano, że podstawową metodą polepszenia temperaturowej stabilności rezonansowej przetworników piezoceramicznych na bazie PZT jest dobór odpowiedniego składu chemicznego. Dotyczy to szczególnie pierwiastków podstawianych w pozycje B opisywanego układu. Ze wzrostem elektroujemności (EN) pierwiastków B wzrasta stopień kowalentności wiązań, a tym samym spontaniczna deformacja (delta) regularnej komórki elementarnej perowskitu. Piezoceramika staje się ferroelektrycznie twardsza, a jej struktura domenowa stabilniejsza, tzn. słabiej podatna na oddziaływania zewnętrzne, w tym na zmianę temperatury. W konsekwencji maleje delta fr/fr.
EN
It is shown that the choice of proper chemical composition is the basic method of improving thermal resonance stability of the piezoceramic transducers on the PZT basis. It mainly concerns elements substituted in positions B of the described system. With the increase of electronegativity of the B elements, the degree of bond covalence increases and, so does the simultaneous spontaneous deformation of the regular elementary cell of perovskite. Piezoceramics becomes ferroelectrically harder and its domain structure more stable, i.e. less voulnerable to exterior influences e.g. temperature change. As a consequence delta fr/fr decreases.
8
Content available The influence of preparation conditions on the electro-acoustic properties of the PZT-type piezoceramic sensors
Dudek J., Kozielski L., Surowiak Z., Kupriyanov M. F.
Archives of Acoustics
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2000
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Vol. 25, no. 1
35-42
EN
The possibilities of the application of the microstructure analysis, X-ray powder diffraction, and Raman scattering methods for the fast and reliable control of the quality of piezoelectric ceramic sensors at every stage of preparation are shown.
9
Macroscopic description of the non-linear electro-mechanical coupling in ferroelectrics
Bohle U., Kamlah M., Munz D., Tsakmakis C.
Applied Mechanics and Engineering
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2000
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Vol. 5, no 4
959-970
EN
Our objective is the construction of a phenomenological ferroelectricity model for general electro-mechanical loading histories, which is simple enough to be implemented in an FE-code with reasonable expenditure. In this paper, we motivate and verify the one-dimensional formulation of such a model. This is done by introducing remanent polarization and remanent strain as internal variables besides stress, strain, electric field and polarization. Polarization induced anisotropy is taken into account to the extent deemed necessary. For the sake of simplicity, no rate effects are included. By bilinear approximation the following characteristic phenomena of macroscopic ferroelectricity are represented: dielectric hysteresis, polarization induced piezoelectricity, butterfly hysteresis, ferroelastic hysteresis, mechanical depolarization, field dependent coercitive stress.
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