Abstract

    Human vocal folds experience flow-induced vibrations during phonation. Inprevious computational models, the vocal fold dynamics has been treatedwith linear elasticity theory in which both the strain and the displacementof the tissue are assumed to be infinitesimal (referred to as model I). Theeffect of the nonlinear strain, or the geometric nonlinearity, caused by thefinite displacement is yet not clear. In this work, a two-dimensional model isused to study the effect of the geometric nonlinearity (referred to as modelII) on the vocal fold and the airflow. The result shows that even though thedeformation is under 1 mm, i.e., less than 10% of the size of the vocal fold,the geometric nonlinear effect is still significant. Specifically, model I under-predicts the gap width, the flow rate, and the impact stress on the medialsurfaces as compared to model II. The study further shows that the differ-ences are caused by the contact mechanics and more importantly, the fluid-structure interaction that magnifies the error from the small-displacementassumption. The results suggest that using the large-displacement formu-lation in a computational model would be more appropriate for accuratesimulations of the vocal fold dynamics.

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