This Master´s thesis deals with use of finite element method for modeling motion and stress of vocal folds during setting to phonation position. The thesis contains a description of the relevant anatomical structures and of the closely related formation of the human voice. A list of some previously published models of the function of human vocal folds follows. A part of my work was to create a model of geometry of the larynx using CATIA V5 and PTC Creo 2.0 on the basis of data acquired by MRI (magnetic resonance imaging). After that the model was converted into the calculation system Ansys Workbench 15.0 and, for solving contact problems, into Ansys Classic 15.0. To solve given problems, these programs use the finite element method (FEM). Solution was carried out for six different variants simulating individual motions of cartilages, corresponding to the activation of individual muscles. For each variant, the movements and stresses in the soft tissue of the vocal folds were evaluated. For variants with activation of IA, TA and LCA muscle it was also evaluated the contact pressure between the vocal folds. Finally, the thesis mentions the preparation of the model for the activation of the vocal folds movement by the muscles of the larynx.

Στα πλαίσια της διπλωματικής εργασίας αναπτύχθηκε μία εφαρμογή, η οποία προσδιορίζει τις τρεις πρώτες συχνότητες συντονισμού της φωνητικής κοιλότητας κατά τη διαδικασία της φώνησης φωνηέντων. Οι τρεις αυτές συχνότητες παρέχουν επαρκή πληροφορία για τον προσδιορισμό του φωνήεντου. Η φώνηση εξομοιώνεται με σήμα εισόδου το οποίο παρουσιάζει κορυφές σε αναμενόμενες περιοχές συχνοτήτων. Ο προσδιορισμός των συχνοτήτων συντονισμού στηρίζεται στη μέθοδο βραχύχρονης ανάλυσης Fourier. Η εφαρμογή αναπτύχθηκε σε περιβάλλον μVision της Keil, σε γλώσσα προγραμματισμού C, για τον μικροελεγκτή STM32F103RB της ST Microelectronics. / In the context of this thesis an application was developed, that is capable of estimating the first three formant frequencies (resonances of the vocal tract) in the event of voicing of vowels. These three frequencies provide us enough information to determine the vowel that is voiced. The human voice is being emulated by an input signal which has peaks in the anticipated frequency regions. The formant frequencies are being estimated based on the short-time Fourier analysis method. The application was developed in Keil μVision programming suite, in C programming language, for the STM32F103RB microcontroller by ST Microelectronics.

The primary purpose of this investigation was to explore the effects of varying degrees of vocal tract semi-occlusion in Vocal Function Exercises (VFEs) on attainment of pre- established maximum phonation time (MPT) goals in individuals between the ages of 18 and 45 with normal voice. Individuals were randomized into three experimental groups: the traditional VFE with a semi-occluded vocal tract (SOVT), modified /o/ with partial occlusion, and modified /a/ without significant occlusion. For six weeks, the participants completed the four exercises two times each, twice daily on corresponding vocal tract postures assigned by group. Results indicated significant change in percent of MPT goal attained for the traditional VFE group. Neither modified vocal tract group resulted in significant change. Decreased occlusion appears insufficient in producing substantial change in voice production despite increased compliance compared to the traditional VFE group.

Welchen Einfluß hat eine Erkrankung der lautgenerierenden Strukturen auf das Lautprodukt. Wie kann eine Stimmveränderung beschrieben werden? Diese Fragen waren zentrales Thema der Untersuchungen. Es wurde ausschließlich auf Senderseite gearbeitet und das akustische Signal und sein Generierungsmechanismus betrachtet. Zunächst wurden nichtlineare Phänomene in drei Fallstudien betrachtet. Nichtlineare Phänomene sind akustische Ereignisse, die auf ein besonderes Schwingungsverhalten der Stimmlippen zurückzuführen sind. In allen drei Fällen kamen nichtlineare Phänomene am häufigsten bei dem erkrankten Tier vor. In einer weiteren Untersuchung wurde der Harmonischen-Rausch-Abstand auf Hundebellen angewendet. Dieser akustische Parameter wurde bisher noch nicht in der Bioakustik verwendet. Normal klingende Hunde scheinen einen mittleren HNR Bereich einzunehmen, während Hunde mit Dysphonie außerhalb dieses Bereiches liegen. Außerdem wurden Untersuchungen zur Anatomie der Stimmlippen und des Vokaltraktes durchgeführt, um bestimmte Aspekte der laryngealen Stimmgenerierung zu verstehen. Diese Dissertation enthält WAVE-Datein, welche hier heruntergeladen werden können: Attached Audiofiles. / If the sender's physiology or merely the sound generating apparatus is affected by a disease, what impact on voice does it have? How can this vocal change be described? Those questions were the central issue in this work, consequently this work is focussed on the sender's side - the acoustic signal and the mechanism of sound production. First nonlinear phonemena, acoustic events arising from certain vibration patterns of the vocal folds were investigated in three case studies. In all three cases the amount of nonlinear phenomena was higher in the disordered animal. Second, the harmonic-to-noise-ratio (HNR), an acoustic parameter not yet used in animal bioacoustics, was applied to dog barks to quantify dysphonia. Normal sounding dogs occupy a middle HNR range, while dysphonic dogs exceed this range to higher as well as to lower HNR values. Additionally, certain aspects of the vocal fold and vocal tract anatomy were investigated in respect to their significance for laryngeal sound generation. This dissertation contains WAVE-files which can be downloaded here: Attached Audiofiles.

Dans la rééducation selon la Méthode de la paille, on utilise des constrictions du tractus vocal, en particulier une paille (2 à 5mm de diamètre). Le débit de sortie doit être soutenu et indépendant de la fréquence. Chez un sujet expert :- PSG, PIO et débit de sortie dépendent du diamètre de la paille- PSG augmente avec la fréquence- débit et PIO sont peu sensibles à la fréquence- la différence [PSG - PIO] (ΔP) est indépendante du diamètre de la paille- le ΔP est identique au seuil de pression phonatoire (SPP) - sur les constrictives (/z/, /ʁ/ et /ʒ/), le ΔP est au-dessus du SPP- dans les enchaînements [constrictive - voyelle], le débit reste constant et la pression sousglottique baisse modérémentSur une population de 36 adultes sains, la valeur la plus basse du SPP se trouve au fondamental usuel de la voix.Sur une population de 22 sujets, les SPP s'abaissent avec la pratique des exercices. Les examens en fibro- et radiovidéoscopie, pendant et après les exercices montrent que :- les cavités sus-glottiques sont dilatées pendant et après l'exercice- la constriction glottique augmente avec la résistance à la sortie- le plan glottique s'élève légèrement avec la fréquenceDix instrumentistes à vent ont été examinés en fibrovidéoscopie : il y a une adduction des plis vocaux pendant le jeu et une importante activité synergique de la glotte sur le jeu en détaché. Les perspectives dégagées par ce travail intéressent :- la clinique, dans l'exploration des troubles de la voix.- la rééducation et la pédagogie- la phonétique (étude des interactions pavillon - source) / The reeducation according to the Methode of the straw using constrictions of the vocal tract, in particular a straw (2 in 5mm of diameter). The release flow must be steady and independent from the frequency. At a subject expert in the method: - PSG, PIO and release flow) depend on the diameter of the straw- PSG increases with the frequency- flow and PIO seem little perceptible to the variations of frequency- the difference [PSG - PIO] (ΔP) is independent from the diameter of the straw- the ΔP value is identical to the SPP - on the constrictive (/z/, /ʁ/ et /ʒ/) the ΔP is over the SPP- in the sequences [constrictive - vowel], the flow remains constant and the subglottal pressure falls moderatelyOn a population of 36 healthy adults, the lowest value of the SPP being in fundamental usual of the voice. On a population of 22 subjects, the SPP fall with the practice of the exercises. The examines with fibro- and radiovideoscopia during and after the execution of the exercises show that: - the supraglottal cavities are dilated during and after the exercise- the glottal constriction increases with the release resistance- the glottal plan rise slightly with the frequencyTen wind instrumentalists were examined with fibrovideoscopia: there is a adduction of the vocal folds during the play and an important synergic activity of the glottis during the staccato play.The perspectives cleared by this work could interest:- the clinical exploration of the voice disorders- the voice rehabilitation and pedagogy- the phonetic (study of the interactions [ tract - glottal source])

L'acoustique du conduit vocal est souvent décrite avec de simples modèles ondes planes à une dimension. Cependant, cela n'est pas satisfaisant quand à haute fréquence (à partir d'environ 5 kHz) des variations tridimensionnelles du champ acoustique sont présentes. La théorie acoustique multimodale a été implémentée pour prendre en compte les aspects tridimensionnels de l'acoustique du conduit vocal.Un système expérimental a été conçu pour mesurer avec précision des fonctions de transfert, des champs de pression et des diagrammes de directivité sur des maquettes de conduits vocaux. Les données expérimentales obtenues ont été comparées avec les simulations réalisées avec la théorie implémentée et avec la méthode des éléments finis. Le champ acoustique tridimensionnel et les diagrammes de directivité ont été prédit avec succès par les deux méthodes de simulation. Il a été observé que la propagation de mode acoustique d'ordre supérieur induit des variations tridimensionnelles du champ acoustique, génère des antirésonances et des résonances additionnelles et affecte la directivité du son rayonné de façon significative. L'excentricité de la forme du conduit vocal apparaît comme critique pour l'excitation et la propagation des modes d'ordre supérieur.Il est conclu qu'à haute fréquence (au-delà de 5 kHz), la fonction de transfert du conduit vocal peut avoir des variations significatives dans des intervalles de fréquences petit (de l'ordre de 100 Hz) et dans des régions angulaires restreintes (de l'ordre de 30°) qui nécessitent d'être prise en compte dans les études de la parole qui se focalisent sur les hautes fréquences. / The vocal tract acoustics is often described witha simple one dimensional plane wave approach.However, this is not satisfying when at high frequency(from about 5 kHz) three dimensional variations ofthe acoustic fieldare present. The multimodal acoustic theory has beenimplemented in order to account for the threedimensional aspects ofthe vocal tract acoustics.An experimental setup has been designed to measure accuratelytransfer functions, pressure field maps and directivitypatterns of vocal tract replicas.The experimental data obtained have been compared withsimulations performed with the implemented theory andwith a finite element method.The three dimensional acoustic fields and the directivitypatterns were successfully predicted by both simulationmethods.It has been observed that the propagation of higher orderacoustical modes, induces three dimensional variations ofthe acoustic field, generates anti-resonances andadditional resonances, and significantly affects the directivityof the radiated sound.The eccentricity of thevocal tract shape appears as critical for the excitation and thepropagation of the higher order acoustical modes.It is concluded thatat high frequency (above 5 kHz), the transfer functionof the vocal tract can have significant variationswithin short frequency intervals (of the order of 100Hz) and within small angular regions (of the order of30°) which need to be taken into account inthe studies of speech which focus on high frequencies.

In the first part of this master's thesis there is briefly presented the biomechanics of the human voice creation and an overview of the hitherto published computational models of the vocal tract and dissemination of the acoustic waves around the human head. The second part of the thesis deals with the creation of the computational model of a dissemination of the acoustic waves through vocal tract and further into a space around the head during the pronouncing of the Czech vowel /a:/. The vocal tract is excited by a harmonic signal in the place of vocal chords. On the surface of the vocal tract and the part of the head including hair and skin there is defined an acoustic absorption. The dissemination of the acoustic waves in the vocal tract, in the near field around the mouth, in the area around the head and in the points on the cheeks is detailed mapped. The dissemination of the acoustic waves is analyzed in the points where the speech microphones are placed. Acoustic pressure dependence on frequency, transmission functions between defined points and the acoustic pressure amplitudes depending on the distance from the mouth are obtained. In particular, the frequency distortion of the spectra is observed at the points indicated. Furthermore, the radiation impedance in the mouth area is evaluated. The results obtained are compared with the results of the hitherto published experimental measurements and can be used for the exact measurement of human voice or for the frequency correction of the microphones during the scann of the speech and sing placced in the analyzed points.

The modal and spectral characteristic belongs among important human acoustic spaces of vocal tract. They occur at generating vowels and other acoustic aspects of human speech. We can observe the resonant phenomena of acoustic cavity of vocal tract in the human speech spectrum, primary however at vowels generation. However near vocal tract occurs series of frequency tops in the spectrum of vowels, which necessarily may not be resonant origin. That is why sometimes quite difficult assign is right frequency tops to resonant tops of acoustic cavity. It consist in operate of acoustic excitation of vocal tracts. The pronounced of vowels loudly and in a whisper has different excitation of vocal tract. At generating vowels loudly is excited by scheme of harmonic components outspread to fundamental frequency of glottis. At talking in a whisper is vocal tract excited by continuous spectrum generated by turbulent fluxion of exhaled flatus over glottis. We give a name "formant" to a frequency, at which happens to resonance of acoustic space. Aim of this work is analysis of Czech vowels formants generated loudly and in a whisper. Experimental metering of these formants was performed on human vocalic tract for all vowels. Further then on artificially created vocalic tracts for vowels A, I. Then were modal characteristics of vocal cavity for vowels A, I, tested by method of final elements with the help of computing program ANSYS. In this work were surveyed courses of acoustic pressures for individual formants, influence sizes vocal tract and influence of correct mouth opening on formants. Also has been effected computational simulation of harmonic excitation on tract by side of glottis.

Master thesis deals with creating of the numerical model of the human vocal folds. Calculation algorithm is designed to include vocal chordsinteraction with the air flow. Analysis of the results achieved by the numerical simulations and calculations are focused on the pressure and velocity conditions in the areas under vocal folds, between vocal folds and above vocal folds. Movement and stress analysis of individual layers of vocal folds has been made. This analysis is limited only for physiological health vocal folds without pathology and disease. Modal analysis of structural and acoustic environment, backround research of vocal folds function and summary of some published overviews of numerical models is part of this work.

Master thesis deals with creating numerical model of the human vocal folds. Calculation algorithm includes interaction between vocal chords and the air flow. Modal analysis of structural and acoustic environment, backround research of vocal folds function and summary of some published overviews of numerical models are parts of this work. Analysis of the results achieved by the numerical simulations and calculations are focused on the pressure and velocity conditions in the areas under vocal folds, between vocal folds and above vocal folds. Movement and stress analysis of individual layers of vocal folds has been made. Impact of tissue thickness on resulting behaviour has been assessed.