Sensitivity of a continuum vocal fold model to geometric parameters, constraints, and boundary conditions.

The influence of key dimensional parameters, motion constraints, and boundary conditions on the modal properties of an idealized, continuum model of the vocal folds was investigated. The Ritz method and the finite element method were used for the analysis. The model's vibratory modes were determined to be most sensitive to changes in the anterior-posterior length of the vocal fold model, due to the influence of three-dimensional stress components acting in the transverse plane. Anterior/ posterior boundary conditions were found to have a significant influence on the vibratory response. Overestimation of modal frequencies resulted when vibration of the structure was restricted to the transverse plane. The overestimation of each modal frequency was proportional to the ratio of longitudinal to transverse Young's modulus, and was significant for ratio values less than 20.