A simple-shear rheometer for linear viscoelastic characterization of vocal fold tissues at phonatory frequencies
A simple-shear rheometer for linear viscoelastic characterization of vocal fold tissues at phonatory frequencies
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DOI：
10.1121/1.2946715
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发表时间：
2008-08-01
影响因子：
2.4
通讯作者：
Rodriguez, Maritza L.
中科院分区：
文献类型：
--
作者：
Chan, Roger W.;Rodriguez, Maritza L.
以前报道的人类声带覆盖物或粘膜的线性粘弹性剪切特性是基于扭转流变学的，测量范围限于低音频，最高可达80赫兹左右。本文描述了一种定制的、控制应变的、线性的、单剪切的流变仪系统的设计和验证，该系统能够在发声频率下对粘弹性剪切特性进行直接的经验测量。组织试件在两个平行的刚性亚克力平板之间受到简单剪切，直线电机通过上板产生试件的平移正弦位移，下板传递由试件的粘弹性响应产生的谐剪切力。试件的位移由线性可变差动变压器测量，剪切力由压电式换能器测量。通过用加速度计进行振动实验，评估了这些系统部件的频率响应特性。测量了标准ANSI S2.21聚氨酯材料和人体声带覆盖试件的粘弹性剪切模量(G(‘)和G(’))，并估计了系统的信号和噪声水平。初步结果表明，该流变仪可以提供有效和可靠的声带固有层标本的流变学数据，频率高达250赫兹，很好地进入发声范围。(C)2008年美国声学学会。
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. (C) 2008 Acoustical Society of America.