ON THE USE OF NEGATIVE CAPACITANCE SHUNT CIRCUITS FOR ATTENUATING STRUCTURAL VIBRATIONS
With the aim of attenuating structural vibrations, a shunted piezoelectric element bonded to a mechanical structure can be designed in such a way that a pure resistive circuit is obtained. Various circuit layouts for the shunt have been used, from the classical purely resistive and the RL topology (in series or parallel configuration, with large inductances simulated by using operational amplifiers) to the more recently proposed topology R(-C) (also in series or parallel configuration). Independently from the shunt architecture, the design starts by taking into account that the piezoelectric element behaves like a capacitor plus a controlled voltage source. In this way, the effect of the negative shunt capacitance is to cancel the internal capacitance of the piezoelectric element. Then, the equivalent circuit is simplified and can be represented by a controlled voltage source and a resistor. From the mechanical point of view, this circuit provides a passive damping system, which is frequency-independent. Since negative capacitors are required, an operational amplifier-based negative impedance converter (NIC) is needed. This paper is focused on the shunt circuits used in conjunction with negative capacitors as applied to structures for the purpose of attenuating noise and vibration. The NIC circuit is presented together with the basic equations that represent the system. The two possible configurations, in series, or, in parallel, are analyzed and their behavior and performance are compared. Finally, some experimental results involving simple mechanical structures are reported, indicating a more suitable design for passive damped applications of mechanical systems.
L.F.LEUCAS E.C.DIAS D.A.RADE P.CARDOSO V.STEFFEN,Jr E.BAARS
School of Mechanical Engineering - Federal University of Uberlandia,2121 Joao Naves de Avila Av., Ca EMBRACO, Rui Barbosa St., 1020 Joinville, 89219-901, Brazil
国际会议
The 22nd International Congress of Refrigeration(第22届国际制冷大会)
北京
英文
2007-08-21（万方平台首次上网日期，不代表论文的发表时间）