A self-oscillating biophysical computer model of the elongated vocal fold.

A new three-dimensional model is developed to simulate the self-oscillation of the elongated vocal folds. This model allows for large deformation and longitudinal displacement. The displacement boundary condition is applied on the posterior side to represent the elongation of vocal fold length by the cricothyroid or the thyroarytenoid muscles. After this model is verified by comparing its outputs using modal analysis and principle component analysis with those of previous models and experimental studies, it is applied to simulate the vibration of elongated vocal fold. Numerical simulation showed that longitudinal elongation increases the y-direction normal stress, decreases the lateral maximum displacement, and increases the fundamental frequency. These results agree with experimental measurements from an excised larynx setup, which suggests that the proposed elongation vocal fold model could be a useful tool to investigate voice production and the control of vocal fold vibration.