Browsing by Author "Nečásek Jakub"
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- ItemActive acoustic metasurface with an array of piezoelectric membranes and local control of acoustic impedance(International Institute of Acoustics and Vibration, IIAV, 2018-01-01) Václavík Jan; Nečásek Jakub; Mokrý Pavel; Steiger Kateřina
- ItemAdaptive acoustic metasurfaces for the active sound field control(Asociación de Acústicos Argentinos, 2016-01-01) Steiger Kateřina; Mokrý Pavel; Václavík Jan; Psota Pavel; Doleček Roman; Vápenka David; Nečásek Jakub; Koldovský Zbyněk
- ItemAdaptive acoustic metasurfaces for the noise shielding(International Institute of Acoustics and Vibration, IIAV, 2017-01-01) Mokrý Pavel; Václavík Jan; Nečásek Jakub; Psota Pavel; Steiger Kateřina; Vápenka David
- ItemAdaptive systems for vibration transmission suppression by means of piezoelectric elements with tunable elasticity(VÚTS, a. s. Liberec, 2015-01-01) Kodejška Miloš; Mokrý Pavel; Steiger Kateřina; Václavík Jan; Márton Pavel; Nečásek Jakub
- ItemComparison of Analog Front-ends for Digital Synthetic Impedance Device(Institute of Electrical and Electronics Engineers Inc., 2017-01-01) Nečásek Jakub; Václavík Jan; Marton PavelPiezoelectric actuator connected to the digital synthetic-impedance device (DSID) represents a modern approach for vibration damping. For efficient use of DSID there are requirements for low input-to-output time delay and high output impedance of the DSID's main part - the voltage controlled current source. In this paper we present two types of these analogue front-ends. The first discussed circuit is based on the voltage compensation method, while the second on the current compensation method - Howland current pump. We compare directly measured output impedance, input-to-output time delay and also the relative error between synthesized and prescribed impedance. Final part of the article is devoted to discussion of practical aspects of these two implementations. Discussed is the possibility to offset voltage at the output, tolerance of passive elements and options for tuning of the output impedance.
- ItemDigital synthetic impedance for application in vibration damping(AIP Publishing LLC, 2016-01-01) Nečásek Jakub; Václavík Jan; Márton Pavel
- ItemFast and Portable Precision Impedance Analyzer for Application in Vibration Damping(IEEE, 345 E 47TH ST, NEW YORK, NY 10017 USA, 2015-01-01) Nečásek Jakub; Václavík Jan; Márton Pavel
- ItemNoise transmission through active acoustic metamaterials in the negative elasticity regime(International Institute of Acoustics and Vibration (IIAV), 1418 Wiggins Hall, Auburn, AL 36849, USA, 2015-01-01) Mokrý Pavel; Václavík Jan; Nečásek Jakub; Steiger Kateřina; Psota Pavel; Doleček Roman
- ItemNumerical environment for modeling and analyzing transients in static VAR compensators(2020-01-01) Kukačka Leoš; Nečásek Jakub; Novák Miroslav
- ItemPortable equipment for measuring high ozone concentrations(2020-01-01) Pokorný Pavel; Nečásek Jakub
- ItemSuppression of noise emission by means of piezoelectric elements with tunable elasticity(VÚTS, a. s. Liberec, 2015-01-01) Steiger Kateřina; Mokrý Pavel; Václavík Jan; Márton Pavel; Nečásek Jakub; Psota Pavel; Doleček Roman; Lédl Vít
- ItemThe elastic properties of an actively controlled piezoelectric transducer: Measurement, analysis and tuning(Elsevier BV, 2018-01-01) Márton Pavel; Nečásek Jakub; Václavík Jan; Mokrý PavelWe report on the development of a method for the measurement of the effective stiffness of a piezoelectric transducer which is bonded to a vibration control system and operated using an approach known as active elasticity control (AEC). Using high-accuracy measurement techniques it is shown that the effective stiffness of the transducer can reach negative values in a certain frequency range, when a suitable active shunt circuit is connected to its electrodes. Extensive analysis proves the consistency of mechanical and electrical measurements of the dynamically loaded piezoelectric transducer compared with the AEC model. A method which allows the computation of adjustments to the active shunt circuit based on the vibration control device’s measured mechanical transfer function is developed. The applicability of the method to a real vibration control system is also demonstrated.