PMID- 17614489
OWN - NLM
STAT- MEDLINE
DCOM- 20070801
LR  - 20070706
IS  - 1520-8524 (Electronic)
IS  - 0001-4966 (Linking)
VI  - 122
IP  - 1
DP  - 2007 Jul
TI  - A multiple degree of freedom electromechanical Helmholtz resonator.
PG  - 291-301
AB  - The development of a tunable, multiple degree of freedom (MDOF) electromechanical 
      Helmholtz resonator (EMHR) is presented. An EMHR consists of an orifice, backing 
      cavity, and a compliant piezoelectric composite diaphragm. Electromechanical 
      tuning of the acoustic impedance is achieved via passive electrical networks 
      shunted across the piezoceramic. For resistive and capacitive loads, the EMHR is 
      a 2DOF system possessing one acoustic and one mechanical DOF. When inductive 
      ladder networks are employed, multiple electrical DOF are added. The dynamics of 
      the multi-energy domain system are modeled using lumped elements and are 
      represented in an equivalent electrical circuit, which is used to analyze the 
      tunable acoustic input impedance of the EMHR. The two-microphone method is used 
      to measure the acoustic impedance of two EMHR designs with a variety of 
      resistive, capacitive, and inductive shunts. For the first design, the data 
      demonstrate that the tuning range of the second resonant frequency for an EMHR 
      with non-inductive shunts is limited by short- and open-circuit conditions, while 
      an inductive shunt results in a 3DOF system possessing an enhanced tuning range. 
      The second design achieves stronger coupling between the Helmholtz resonator and 
      the piezoelectric backplate, and both resonant frequencies can be tuned with 
      different non-inductive loads.
FAU - Liu, Fei
AU  - Liu F
AD  - Department of Mechanical and Aerospace Engineering, University of Florida, 
      Gainesville, Florida 32611-6250, USA.
FAU - Horowitz, Stephen
AU  - Horowitz S
FAU - Nishida, Toshikazu
AU  - Nishida T
FAU - Cattafesta, Louis
AU  - Cattafesta L
FAU - Sheplak, Mark
AU  - Sheplak M
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - J Acoust Soc Am
JT  - The Journal of the Acoustical Society of America
JID - 7503051
SB  - IM
MH  - Acoustics/*instrumentation
MH  - *Aircraft
MH  - Compliance
MH  - Electric Capacitance
MH  - Electric Impedance
MH  - Equipment Design
MH  - Models, Theoretical
MH  - Noise/*prevention & control
MH  - Vibration
EDAT- 2007/07/07 09:00
MHDA- 2007/08/02 09:00
CRDT- 2007/07/07 09:00
PHST- 2007/07/07 09:00 [pubmed]
PHST- 2007/08/02 09:00 [medline]
PHST- 2007/07/07 09:00 [entrez]
AID - 10.1121/1.2735116 [doi]
PST - ppublish
SO  - J Acoust Soc Am. 2007 Jul;122(1):291-301. doi: 10.1121/1.2735116.