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Experimental and computer modelling study of glottal closing velocity during phonation
Horáček, Jaromír ; Radolf, Vojtěch ; Bula, Vítězslav ; Šidlof, P. ; Geneid, A. ; Laukkanen, A. M.
This preliminary study shows that the impact stress between the colliding vocal folds during phonation should not be evaluated from the maximum velocity of the glottal closing because the velocity of the closing diminishes just before the glottal closure. This phenomenon, which can be caused by a pressure cushion effect in the fast narrowing glottal gap, is demonstrated with measurements from high speed camera images recorded from human and on a physical laboratory model for vowel [u:] phonation and on a three-mass computer model employing a Hertz model of impact force. For a more detailed future study of this phenomenon a faster camera has to be used. \n
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Numerical investigation of acoustic characteristics of 3D human vocal tract model with nasal cavities
Vampola, T. ; Štorkán, J. ; Horáček, Jaromír ; Radolf, Vojtěch
Acoustic resonance characteristics of 3D human vocal tract model without and with nasal and\nparanasal cavities were computed. Nasal cavities (NC) form the side branches of the human vocal tract and exhibit antiresonance and resonance properties which influence the produced voice quality. Developed FE models of acoustic spaces of nasal and vocal tract for vowel /a:/ are used to study the influence of (NC) on phonation. Acoustics frequency-modal characteristics are studied by modal analysis and numerical simulation of acoustic signals in time domain is performed by transient analysis of the FE models.
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Experimental modelling of phonation using artificial models of human vocal folds and vocal tracts
Horáček, Jaromír ; Radolf, Vojtěch ; Bula, Vítězslav ; Košina, Jan
The study provides information on experimental research on a complete 1:1 scaled model of human phonation. The model includes human lungs, the trachea, the laryngeal part with artificial vocal folds and the vocal tracts designed for different vowels. The measurement set up enables modelling the time signals not easily measured in humans during phonation as for example fluctuations of the subglottic, laryngeal and oral pressures measured simultaneously with the glottis opening and the glottis area registered by a high-speed camera. The simulation of phonation is performed in the ranges of the airflow rate and the subglottic pressure typical for a normal humans' physiology.
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ENGINEERING MECHANICS 2016 - Book of full texts
Zolotarev, Igor ; Radolf, Vojtěch
The 22nd International Conference EM2016 aims to provide a forum for researchers, industry practitioners, engineers and postgraduate scholars to promote exchange and disseminate knowledge and experiences of the most recent results and advances in a wide range of topics in Engineering Mechanics, including, but not limited to: Biomechanics, Dynamics, Fluid Mechanics, Fracture Mechanics, Kinematics, Mechanics of Solids, Mechatronics, Reliability of Structures and Thermomechanics.
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Acoustic resonance characteristics of the human vocal tract with respect to a soft tissue
Radolf, Vojtěch ; Horáček, Jaromír
A mathematical model, which can help to clarify physical background of an influence of the soft tissue of vocal cavities on the formant frequencies, has been extended. Strong acoustic-structural interaction is demonstrated on the vocal tract cavity for vowel /u:/ prolonged by a tube that is used for voice training and therapy purposes. The glottis is closed by a yielding wall, considering a mass, compliance and structural damping. Viscous losses of the acoustic cavities and radiation impedance at the output are assumed. Significant change in the first acoustic resonance frequency caused by the compliance of the soft tissue at the glottis corresponds to the data found experimentally in earlier study.
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