Mechanical Engineering, 585 Purdue Mall, Purdue University, West Lafayette, IN 47907, USA.
J Biomech. 2011 Jun 3;44(9):1729-34. doi: 10.1016/j.jbiomech.2011.03.037. Epub 2011 Apr 15.
In voice research, in vitro tensile stretch experiments of vocal fold tissues are commonly employed to determine the tissue biomechanical properties. In the standard stretch-release protocol, tissue deformation is computed from displacements applied to sutures inserted through the thyroid and arytenoid cartilages, with the cartilages assumed to be rigid. Here, a non-contact optical method was employed to determine the actual tissue deformation of vocal fold lamina propria specimens from three excised human larynges in uniaxial tensile tests. Specimen deformation was found to consist not only of deformation of the tissue itself, but also deformation of the cartilages, as well as suture alignment and tightening. Stress-stretch curves of a representative load cycle were characterized by an incompressible Ogden model. The initial longitudinal elastic modulus was found to be considerably higher if determined based on optical displacement measurements than typical values reported in the literature. The present findings could change the understanding of the mechanics underlying vocal fold vibration. Given the high longitudinal elastic modulus the lamina propria appeared to demonstrate a substantial level of anisotropy. Consequently, transverse shear could play a significant role in vocal fold vibration, and fundamental frequencies of phonation should be predicted by beam theories accounting for such effects.
在语音研究中，通常采用体外拉伸伸展实验来测量声带组织的生物力学特性。在标准的拉伸释放实验方案中，通过对穿过甲状腺和杓状软骨插入的缝线施加的位移来计算组织变形，假设软骨是刚性的。在这里，我们采用一种非接触式光学方法，从三个切除的人喉中确定了单向拉伸实验中声带固有层标本的实际组织变形。发现标本的变形不仅包括组织本身的变形，还包括软骨的变形，以及缝线的对准和紧固。用不可压缩的 Ogden 模型对代表性的载荷循环的应力-应变曲线进行了特征描述。如果基于光学位移测量来确定初始纵向弹性模量，则会发现其值远高于文献中报道的典型值。这些发现可能会改变我们对声带振动力学的理解。鉴于固有层的高纵向弹性模量，其表现出相当大的各向异性。因此，横向剪切可能在声带振动中起重要作用，并且应该通过考虑到这种效应的梁理论来预测发音的基频。
