The voice is the primary mode of communication for humans. Because the voice is so important, voice disorders tend to severely diminish quality of life. A better understanding of the physics of voice production can help to improve treatment of voice disorders. For this thesis research a self-oscillating synthetic vocal fold model was developed, compared with previous synthetic vocal fold models, and used to explore the physical effects of augmentation injections on vibration dynamics. The research was conducted in two stages. First, four vocal fold models were evaluated by quantifying onset pressure, frequency, maximum glottal gap, flow rate, and medial surface motion. The newly developed model, differentiated from the other models by the inclusion of more layers, adjusted geometry, and an extremely soft superficial lamina propria layer, was included in this study. One of the models, created using MRI-derived geometry, had the most defined mucosal wave. The newly-developed model had the lowest onset pressure, flow rate, and smallest maximum glottal width, and the model motion compared very well with published excised human larynx data. Second, the new model was altered to simulate bowing by decreasing the volume of the body layer relative to that of a normal, unbowed model. Two models with varying degrees of bowing were created and tested while paired with normal models. Pre- and post-injection data (onset pressure, vibration frequency, glottal flow rate, open quotient, and high-speed image sequences) were recorded and compared. General pre- to post-injection trends included decreased onset pressure, glottal flow rate, and open quotient, and increased vibration frequency. Additionally, there was a decrease in mucosal wave velocity and an increase in phase angle. The thesis results are anticipated to aid in better understanding the physical effects of augmentation injections, with the ultimate goal of obtaining more consistent surgical outcomes, and also to contribute to the advancement of voice research through the development of the new synthetic model.



College and Department

Ira A. Fulton College of Engineering and Technology; Mechanical Engineering



Date Submitted


Document Type





vocal folds, vocal fold modeling, mucosal wave, high-speed imaging, injection laryngoplasty, larynx, medial surface, augmentation, Preston R. Murray