TY - JOUR
T1 - A simple-shear rheometer for linear viscoelastic characterization of vocal fold tissues at phonatory frequencies
AU - Chan, Roger W.
AU - Rodriguez, Maritza L.
N1 - Funding Information:
This work was supported by the National Institute on Deafness and Other Communication Disorders, NIH Grant No. R01 DC006101. The authors wish to thank Min Fu and Bokkyu Lee for their assistance in rheological data collection and data analysis. Special thanks are extended to Alan McMullen, Kirk Biegler, and Troy Nickel of the ElectroForce Systems Group, Bose Corporation for their contributions to the design and validation of the rheometer.
PY - 2008
Y1 - 2008
N2 - Previous studies reporting the linear viscoelastic shear properties of the human vocal fold cover or mucosa have been based on torsional rheometry, with measurements limited to low audio frequencies, up to around 80 Hz. This paper describes the design and validation of a custom-built, controlled-strain, linear, simple-shear rheometer system capable of direct empirical measurements of viscoelastic shear properties at phonatory frequencies. A tissue specimen was subjected to simple shear between two parallel, rigid acrylic plates, with a linear motor creating a translational sinusoidal displacement of the specimen via the upper plate, and the lower plate transmitting the harmonic shear force resulting from the viscoelastic response of the specimen. The displacement of the specimen was measured by a linear variable differential transformer whereas the shear force was detected by a piezoelectric transducer. The frequency response characteristics of these system components were assessed by vibration experiments with accelerometers. Measurements of the viscoelastic shear moduli (G′ and G″) of a standard ANSI S2.21 polyurethane material and those of human vocal fold cover specimens were made, along with estimation of the system signal and noise levels. Preliminary results showed that the rheometer can provide valid and reliable rheometric data of vocal fold lamina propria specimens at frequencies of up to around 250 Hz, well into the phonatory range.
AB - Previous studies reporting the linear viscoelastic shear properties of the human vocal fold cover or mucosa have been based on torsional rheometry, with measurements limited to low audio frequencies, up to around 80 Hz. This paper describes the design and validation of a custom-built, controlled-strain, linear, simple-shear rheometer system capable of direct empirical measurements of viscoelastic shear properties at phonatory frequencies. A tissue specimen was subjected to simple shear between two parallel, rigid acrylic plates, with a linear motor creating a translational sinusoidal displacement of the specimen via the upper plate, and the lower plate transmitting the harmonic shear force resulting from the viscoelastic response of the specimen. The displacement of the specimen was measured by a linear variable differential transformer whereas the shear force was detected by a piezoelectric transducer. The frequency response characteristics of these system components were assessed by vibration experiments with accelerometers. Measurements of the viscoelastic shear moduli (G′ and G″) of a standard ANSI S2.21 polyurethane material and those of human vocal fold cover specimens were made, along with estimation of the system signal and noise levels. Preliminary results showed that the rheometer can provide valid and reliable rheometric data of vocal fold lamina propria specimens at frequencies of up to around 250 Hz, well into the phonatory range.
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U2 - 10.1121/1.2946715
DO - 10.1121/1.2946715
M3 - Article
C2 - 18681608
AN - SCOPUS:49249099722
SN - 0001-4966
VL - 124
SP - 1207
EP - 1219
JO - Journal of the Acoustical Society of America
JF - Journal of the Acoustical Society of America
IS - 2
ER -