Ing. Petr Hájek, Ph.D.
E-mail:   126528@vutbr.cz  Pracoviště:   Ústav mechaniky těles, mechatroniky a biomechaniky odbor biomechaniky Zařazení:   Odborný asistent Místnost:   A2/601

Vybrané publikace:

• HÁJEK, P.; ŠVANCARA, P.; HORÁČEK, J.; ŠVEC, J.:
  Two-dimensional finite element model of vowel production: properties of self-oscillating vocal folds interacting with fluid flow
  abstrakt
• HÁJEK, P.; ŠVANCARA, P.; HORÁČEK, J.; ŠVEC, J.:
  Effects of Turbulence in FE Model of Human Vocal Folds Self-oscillation,
  Engineering Mechanics 2017, pp.366-369, ISBN 978-80-214-5497-2, (2017), Institute of Thermomechanics, Academy of Sciences of the Czech Republic, v. v. i., Prague
  článek ve sborníku ve WoS nebo Scopus
  akce: ENGINEERING MECHANICS 2017, Svratka, 15.05.2017-18.05.2017
• HÁJEK, P.; ŠVANCARA, P.; HORÁČEK, J.; ŠVEC, J.:
  FE Modelling of the Influence of the Lamina Propria Properties on the Vocal Folds Vibration and Produced Sound for Specific Czech Vowels,
  Computational Mechanics 2016: Book of extended abstracts, pp.23-24, ISBN 978-80-261-0647-0, (2016), University of West Bohemia
  článek ve sborníku ve WoS nebo Scopus
  akce: Computational Mechanics 2016, Špičák, 31.10.2016-02.11.2016
• HÁJEK, P.; ŠVANCARA, P.; HORÁČEK, J.; ŠVEC, J.:
  Numerical Simulation of the Self-oscillating Vocal Folds in Interaction with Vocal Tract Shaped for Particular Czech Vowels,
  Recent Global Research and Education: Technological Challenges: Proceedings of the 15th International Conference on Global Research and Education Inter-Academia 2016, pp.317-323, ISBN 978-3-319-46490-9, (2016), Springer Verlag
  článek ve sborníku ve WoS nebo Scopus
  akce: 15th International Conference on Global Research and Education, INTER-ACADEMIA 2016, Warsaw, Poland, 26.09.2016-28.09.2016
• HÁJEK, P.; ŠVANCARA, P.; HORÁČEK, J.; ŠVEC, J.:
  Numerical Simulation of the Effect of Stiffness of Lamina Propria on the Self-sustained Oscillation of the Vocal Folds,
  Engineering Mechanics 2016, pp.182-185, ISBN 978-80-87012-59-8, (2016), Institute of Thermomechanics, Academy of Sciences of the Czech Republic, v. v. i., Prague
  článek ve sborníku ve WoS nebo Scopus
  akce: Engineering mechanics 2016, Svratka, 09.05.2016-12.05.2016
• HÁJEK, P.; ŠVANCARA, P.; HORÁČEK, J.; ŠVEC, J. G.:
  Finite Element Modelling of the Effect of Stiffness and Damping of Vocal Fold Layers on their Vibrations and Produced Sound,
  Applied Mechanics and Materials, pp.657-664, ISSN 1662-7482, Trans Tech Publications Inc.
  článek v časopise - ostatní, Jost
  akce: Engineering Mechanics 2015, Svratka, 11.05.2015-14.05.2015

Seznam publikací na portálu VUT

Anotace nejvýznamnějších prací:

• HÁJEK, P.; ŠVANCARA, P.; HORÁČEK, J.; ŠVEC, J.:
  Two-dimensional finite element model of vowel production: properties of self-oscillating vocal folds interacting with fluid flow
  abstrakt
  The current study concerns finite element (FE) model of flow-induced self-sustained oscillation of the human vocal folds (VF) in interaction with vocal tract (VT) acoustics. Two dimensional (2D) FE model consists of the fluid model (involving the VT and trachea) and the structure model (the VF). Geometry of the VT was converted from magnetic resonance images (MRI) data for production of a Czech vowels. The VF model is based on widely used Scherer’s M5 geometry with four-layered structure comprising epithelium, superficial lamina propria (SLP), ligament and muscle. For solving fluid-structure interaction explicit coupling scheme is applied with separate solvers for the structure and fluid domain. Acoustic wave propagation is obtained from solution of compressible NS equations. Phonation of the Czech vowels [a:], [i:] and [u:] were simulated and influence of thickness and material characteristics of the SLP on vocal folds vibrations and produced sound were analysed. Using this model was also analyzed the effect of turbulence model in fluid flow calculation. The developed FE model can be used to study the effects of pathological changes in VF tissue such as Reinke’s edem on VF movement and on the produced sound.
• HÁJEK, P.; ŠVANCARA, P.; HORÁČEK, J.; ŠVEC, J.:
  Effects of Turbulence in FE Model of Human Vocal Folds Self-oscillation,
  Engineering Mechanics 2017, pp.366-369, ISBN 978-80-214-5497-2, (2017), Institute of Thermomechanics, Academy of Sciences of the Czech Republic, v. v. i., Prague
  článek ve sborníku ve WoS nebo Scopus
  akce: ENGINEERING MECHANICS 2017, Svratka, 15.05.2017-18.05.2017
  The purpose of the study is to determine whether a turbulence model in fluid flow calculation affects the vocal folds (VF) vibration and the acoustics of human vocal tract (VT). The objective is examined using a two-dimensional (2D) finite element (FE) model of the fluid-structure-acoustic interaction for self- sustained oscillations of the VF. The FE model consists of the models of the VF, the trachea and a simplified model of the human VT. The developed FE model includes large deformations of the VF tissue and VF contact interrupting the airflow during glottis closure. The airflow is modelled by the unsteady viscous compressible Navier-Stokes equations, without and with the Shear Stress Transport (SST) turbulence model. Fluid-structure interaction (FSI) and morphing of the fluid mesh are realized using Arbitrary Lagrangian- Eulerian (ALE) approach. The method is applied on the FE model of the VT shaped for the Czech vowel [a:]. Also effect of varying stiffness of the superficial lamina propria (SLP) is analyzed. The numerical simulations showed that considering of the turbulence affects mainly higher frequencies apparent in a frequency spectrum of the VT acoustics.
• HÁJEK, P.; ŠVANCARA, P.; HORÁČEK, J.; ŠVEC, J.:
  FE Modelling of the Influence of the Lamina Propria Properties on the Vocal Folds Vibration and Produced Sound for Specific Czech Vowels,
  Computational Mechanics 2016: Book of extended abstracts, pp.23-24, ISBN 978-80-261-0647-0, (2016), University of West Bohemia
  článek ve sborníku ve WoS nebo Scopus
  akce: Computational Mechanics 2016, Špičák, 31.10.2016-02.11.2016
  Presented two-dimensional (2D) finite element (FE) model of the flow-induced self-oscillation of the human vocal folds (VF) enables solving fluid-structure-acoustic interaction occurring during phonation. The aim is to analyze the acoustic wave propagation for Czech vowels [a:], [i:] and [u:] on change of the superficial lamina propria (SLP) properties. The 2D FE model includes setting to phonatory position with the VF pretension, large deformation of VF tissues and their contact (structural model) and unsteady viscous compressible airflow separated during glottal closure and described by the Navier-Stokes (NS) equations (fluid model, comprises of the FE model of the trachea, glottis and the vocal tract (VT)). The fluid mesh morphs according to the VF motion (Arbitrary Lagrangian-Eulerian approach) and geometry of the aforementioned VT was obtained from MRI. Such a symmetrical or unsymmetrical variation of the SLP properties accompanies diverse VF pathologies, thus numerical results may reveal new phenomena of them.
• HÁJEK, P.; ŠVANCARA, P.; HORÁČEK, J.; ŠVEC, J.:
  Numerical Simulation of the Self-oscillating Vocal Folds in Interaction with Vocal Tract Shaped for Particular Czech Vowels,
  Recent Global Research and Education: Technological Challenges: Proceedings of the 15th International Conference on Global Research and Education Inter-Academia 2016, pp.317-323, ISBN 978-3-319-46490-9, (2016), Springer Verlag
  článek ve sborníku ve WoS nebo Scopus
  akce: 15th International Conference on Global Research and Education, INTER-ACADEMIA 2016, Warsaw, Poland, 26.09.2016-28.09.2016
  The study presents a two-dimensional (2D) finite element (FE) model which consists of the vocal folds (VF), the trachea and idealized vocal tract (VT) shaped for Czech vowels [a:], [i:] and [u:] created from magnetic resonance images (MRI). Such configuration enables solving fluid-structure-acoustic interaction, flow-induced self-oscillations of the VF and acoustic wave propagation in the VT by explicit coupling scheme with two separate solvers for structure and fluid domain.
• HÁJEK, P.; ŠVANCARA, P.; HORÁČEK, J.; ŠVEC, J.:
  Numerical Simulation of the Effect of Stiffness of Lamina Propria on the Self-sustained Oscillation of the Vocal Folds,
  Engineering Mechanics 2016, pp.182-185, ISBN 978-80-87012-59-8, (2016), Institute of Thermomechanics, Academy of Sciences of the Czech Republic, v. v. i., Prague
  článek ve sborníku ve WoS nebo Scopus
  akce: Engineering mechanics 2016, Svratka, 09.05.2016-12.05.2016
  A two-dimensional (2D) finite element (FE) model of the fluid-structure-acoustic interaction during self- sustained oscillation of the human vocal folds (VF) is presented in this paper. The aim is to analyze the effect of stiffness of lamina propria on VF vibrations. Such stiffness change can be caused by some VF pathologies. The developed FE model consists of the FE models of the VF, trachea and a simplified human vocal tract. The vocal tract model shaped for simulation of phonation of Czech vowel [a:] was created by converting data from the magnetic resonance images (MRI). The developed FE model includes VF contact, large deformations of the VF tissue, fluid-structure interaction (FSI), moving boundary of the fluid mesh (Arbitrary Lagrangian-Eulerian (ALE) approach), airflow separation during the glottis closure and solution of unsteady viscous compressible airflow described by the Navier-Stokes equations. The numerical simulations showed that higher values of lamina propria Young's modulus (stiffer lamina propria) result in a decrease of the maximum glottis opening. Stiffer lamina propria also requires the use of higher subglottal pressure to initiate self-sustained vibration of the VF.