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The reverse task of discrete mechatronic vibration systems with negative stiffness and capacitance elements

Białas K., Buchacz A., Gałęziowski D.

Archive of Mechanical Engineering

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2015

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Vol. LXII, nr 2

145--155

EN

By the use of different distribution methods of dynamical characteristics in the form of slowness function, mechatronic discrete systems have been synthesized. Each model consists of mechanical discrete part and a piezostack actuator connected to LxRxCx external network that has to comply with dynamical requirements in the form of poles and zeros. External network can work within different configurations. In this paper, one investigates the influence of negative parameters of stiffness in mechanical replacement models and capacitance in final mechatronic structures, after dimensionless transformations and retransformations.

PL

Korzystając z wybranych metod rozkładu funkcji charakterystycznej w postaci powolności zsyntezowano mechatroniczne dyskretne układy drgające. W każdym przypadku układ zbudowano z mechanicznego modelu dyskretnego oraz piezo aktuatora typu „stack” połączonego z zewnętrznym obwodem elektrycznym LxRxCx . Układy zaprojektowano ze względu na wymagania dynamiczne w postaci biegunów i zer. Zewnętrzny układ elektryczny może występować w różnych konfiguracjach. W pracy, po bezwymiarowych transformacjach i retransformacjach, zbadano wpływ ujemnych parametrów: sztywności w mechanicznym modelu zastępczym oraz pojemności w finalnym układzie mechatronicznym LxCx , na charakterystyki rozważanych układów.

2

The reverse task of discrete mechatronic vibration systems with negative stiffness and capacitance elements

Białas K., Buchacz A., Gałęziowski D.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2013

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z. 101

13--14

EN

Designing of the mechanical and mechatronic systems by use of different synthesis methods, in relation to resonant and antiresonant frequency requirements is well known problem]. Due to practical application usage of additional damping methods: active or passive dampers [5] and piezoelectric actuators it’s recently more and more common. Identification and selection of the various parameters of the considered models are very important from final behavior point of view. Basing on current approaches for negative stiffness mechanisms and capacitance elements identification and investigations for negative parameters on various discrete mechatronic structures have been done.

3

Negative Stiffness Demonstrated by NiAl Nanofilms

Babicheva R. I., Bukreeva K. A., Dmitriev S. V., Mulyukov R. R., Zhou K.

Computational Methods in Science and Technology

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2013

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Vol. 19, No. 3

127--135

EN

This paper studies the uniaxial strain control tension of NiAl nanofilms via molecular dynamics simulations. The nanofilm deforms elastically until fracture at tensile strain is as large as 37%. The stress-strain curve has a range where tensile deformation develops at decreasing tensile stress, thus indicating negative stiffness. Such deformation is thermodynamically unstable and the nanofilm splits into domains with two different values of elastic strain. Deformation within the unstable range is controlled by motion of the domain walls, resulting in the domains with larger strain grow at the expense of the domains with smaller strain.