Titze I R, Talkin D T
J Acoust Soc Am. 1979 Jul;66(1):60-74. doi: 10.1121/1.382973.
Simulation of glottal volume flow and vocal fold tissue movement was accomplished by numerical solution of a time-dependent boundary value problem, in which nonuniform, orthotropic, linear, incompressible vocal fold tissue media were surrounded by irregularly shaped boundaries, which were either fixed or subject to aerodynamic stresses. Spatial nonuniformity of the tissues was of the layered type, including a mucosal layer, a ligamental layer, and muscular layers. Orthotropy was required to stabilized the vocal folds longitudinally and to accomodate large variations in muscular stress. Incompressibility and vertical motions at the golttis played an important role in producing and sustaining phonation. A nominal configuration for male fundamental speaking pitches was selected, and the regulation of fundamental frequency, intensity, average volume flow, and vocal efficiency was investigated in terms of variations around this nominal configuration. Parameters which were varied consisted of geometrical factors such as length, thickness, and depth, factors for shaping the glottis, as well as tissue elasticities, tissue viscosities, and subglottal pressure. Since nonlinear stress-strain properties were not included, subglottal pressure did not produce a pronounced effect upon fundamental frequency under these somewhat edealized conditions F0 rasing correlated strongly with increased tension in the ligament, and somewhat with increasing tension in the vocalis. F0 lowering correlated with increase in vocal fold length when the tensions were held constant, but not with increase in vocal fold thickness. Vocal intensity and efficiency are shown to have local maxima as the configurational parameters are varied one at a time. It appears that oral acoustic power output and vocal efficiency can be maximized by proper adjustments of longitudinal tension of nonmuscular (mucosal and ligamental) tissue layers in relation to muscular layers. Quantitative verification of the "body-cover" theory is therefore suggested, and several further implications with regard to control of the human larynx are considered.
通过求解一个与时间相关的边值问题来模拟声门容积流量和声带组织运动，其中非均匀、正交各向异性、线性、不可压缩的声带组织介质被不规则形状的边界所包围，这些边界要么是固定的，要么受到气动应力作用。组织的空间非均匀性为分层类型，包括黏膜层、韧带层和肌肉层。正交各向异性对于纵向稳定声带以及适应肌肉应力的大幅变化是必需的。声门处的不可压缩性和垂直运动在发声和维持发声中起重要作用。选择了男性基本发声音高的标称构型，并围绕该标称构型的变化研究了基频、强度、平均容积流量和发声效率的调节。变化的参数包括几何因素，如长度、厚度和深度，声门形状因素，以及组织弹性、组织粘性和声门下压力。由于未包含非线性应力应变特性，在这些理想化条件下，声门下压力对基频没有产生明显影响。基频升高与韧带张力增加密切相关，与甲杓肌张力增加也有一定关系。当张力保持恒定时，基频降低与声带长度增加相关，但与声带厚度增加无关。当构型参数逐个变化时，发声强度和效率显示出局部最大值。似乎通过适当调整非肌肉（黏膜和韧带）组织层相对于肌肉层的纵向张力，可以使口腔声功率输出和发声效率最大化。因此，有人提出对“主体 - 覆盖”理论进行定量验证，并考虑了关于人类喉部控制的其他一些影响。
