scholarly journals Comparison of a fiber-gel finite element model of vocal fold vibration to a transversely isotropic stiffness model

2017 ◽  
Vol 142 (3) ◽  
pp. 1376-1383 ◽  
Author(s):  
Ingo R. Titze ◽  
Fariborz Alipour ◽  
Douglas Blake ◽  
Anil Palaparthi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Vocal Fold ◽  
Transversely Isotropic ◽  
Element Model ◽  
Vocal Fold Vibration ◽  
Stiffness Model

Influence of Vocal Fold Scarring on Phonation: Predictions from a Finite Element Model

2005 ◽  
Vol 114 (11) ◽  
pp. 847-852 ◽  
Author(s):  
David A. Berry ◽  
Haven Reininger ◽  
Fariborz Alipour ◽  
Diane M. Bless ◽  
Charles N. Ford
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fundamental Frequency ◽  
Viscoelastic Properties ◽  
Vocal Fold ◽  
Human Subjects ◽  
Vocal Folds ◽  
Element Model ◽  
Acoustic Intensity ◽  
Vocal Fold Vibration

Objectives: A systematic study of the influence of vocal fold scarring on phonation was conducted. In particular, phonatory variables such as fundamental frequency, oral acoustic intensity, and phonation threshold pressure (PTP) were investigated as a function of the size and position of the laryngeal scar. Methods: By means of a finite element model of vocal fold vibration, the viscoelastic properties of both normal and scarred vocal fold mucosae were simulated on the basis of recent rheological data obtained from rabbit and canine models. Results: The study showed that an increase in the viscoelasticity of the scarred mucosa resulted in an increase in fundamental frequency, an increase in PTP, and a decrease in oral acoustic intensity. With regard to positioning of the scar, the PTP increased most significantly when the scar was within ±2 mm of the superior-medial junction of the vocal folds. Conclusions: The systematic data obtained in this investigation agree with the general clinical experience. In the future, these findings may be further validated on human subjects as newly emerging technologies such as linear skin rheometry and optical coherence tomography allow the histologic and viscoelastic properties of the normal and scarred vocal fold mucosae to be measured in the clinic.

A finite-element model of vocal-fold vibration

2000 ◽  
Vol 108 (6) ◽  
pp. 3003-3012 ◽  
Author(s):  
Fariborz Alipour ◽  
David A. Berry ◽  
Ingo R. Titze
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Vocal Fold ◽  
Element Model ◽  
Vocal Fold Vibration

Vibration Characteristics of the Vocal Folds

2006 ◽  
Author(s):  
L. Hai ◽  
A. M. Al-Jumaily ◽  
A. Mirnajafi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Vocal Fold ◽  
Vocal Folds ◽  
Element Model ◽  
Vibration Characteristics ◽  
Transverse Isotropic ◽  
Body Theory ◽  
Oscillation Characteristics ◽  
Vocal Fold Nodules

The vibration characteristics of the vocal folds are investigated using a finite element model which incorporates the in-homogeneity and anisotropy of the materials and the irregularity of the geometry. The model employs the cover and body theory to build the structure of the vocal folds and implements measured viscoelastic properties of the mucosa and the transverse isotropic elastic properties of the muscles. It has the potential to simulate some vocal-fold disorders and determine the change in characteristics. To determine the oscillation characteristics of the folds, the eigenfrequency and eigenmodes of the finite element model are determined using the ABAQUS software. The model results compare well with some experiments performed on a silicon vocal fold. It is anticipated that the model will help to identify voice disorders such as vocal-fold paralysis and vocal-fold nodules.

scholarly journals Bayesian Inference of Vocal Fold Material Properties from Glottal Area Waveforms Using a 2D Finite Element Model

2019 ◽  
Vol 9 (13) ◽  
pp. 2735 ◽  
Author(s):  
Paul J. Hadwin ◽  
Mohsen Motie-Shirazi ◽  
Byron D. Erath ◽  
Sean D. Peterson
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bayesian Estimation ◽  
Material Properties ◽  
Vocal Fold ◽  
Vocal Folds ◽  
Element Model ◽  
Lumped Element ◽  
Subglottal Pressure ◽  
Contact Pressures

Bayesian estimation has been previously demonstrated as a viable method for developing subject-specific vocal fold models from observations of the glottal area waveform. These prior efforts, however, have been restricted to lumped-element fitting models and synthetic observation data. The indirect relationship between the lumped-element parameters and physical tissue properties renders extracting the latter from the former difficult. Herein we propose a finite element fitting model, which treats the vocal folds as a viscoelastic deformable body comprised of three layers. Using the glottal area waveforms generated by self-oscillating silicone vocal folds we directly estimate the elastic moduli, density, and other material properties of the silicone folds using a Bayesian importance sampling approach. Estimated material properties agree with the “ground truth” experimental values to within 3 % for most parameters. By considering cases with varying subglottal pressure and medial compression we demonstrate that the finite element model coupled with Bayesian estimation is sufficiently sensitive to distinguish between experimental configurations. Additional information not available experimentally, namely, contact pressures, are extracted from the developed finite element models. The contact pressures are found to increase with medial compression and subglottal pressure, in agreement with expectation.

A Validated Finite Element Model of Force in Active and Passive Skeletal Muscle

2010 ◽  
Author(s):  
Duane A. Morrow ◽  
Tammy L. Haut Donahue ◽  
Gregory M. Odegard ◽  
Kenton R. Kaufman
Keyword(s):  
Skeletal Muscle ◽  
Finite Element ◽  
Finite Element Model ◽  
Muscle Activation ◽  
Muscle Force ◽  
Transversely Isotropic ◽  
Element Model ◽  
Fea Model ◽  
Constitutive Formulation ◽  
Force Data

A fully 3D, continuum mechanics based model of skeletal muscle, validated against experimental force data, can be used to computationally solve for individual muscle forces. A constitutive formulation, representing muscle as a transversely isotropic, hyperelastic, and isovolumetric material [1] has been implemented in a finite element model (FEM) of passive skeletal muscle and validated against experimental tension measurements [2]. Of further interest is an expanded formulation that will allow for the addition of muscle activation levels on the overall skeletal muscle force generation. The purpose of this study was to expand the FEA model to include muscle activation and validate it with tests of active skeletal muscle tissue at varied lengths.

Dependence of Elastic Properties of Human Femoral Cortical Bone on Porosity

2015 ◽  
Author(s):  
Maryam Khosroshahi ◽  
Fred Barez ◽  
Amer El-Hage ◽  
James Kao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Cortical Bone ◽  
Elastic Properties ◽  
Transversely Isotropic ◽  
Element Model ◽  
Element Analysis ◽  
Age Related ◽  
The Finite Element Model

Hip fracture is one of the most serious and common health problems among elderly which may lead to permanent disability or death. Hip fracture commonly occurs in the femoral bone, the major bone in the hip joint. Microscopic age-related changes in the structure of cortical bone is one of the factors that is considered to be partially responsible for the increase of fracture risk in elderly. It is of great interest to develop a predictable model of such fractures for the aging population in preparation of a suitable therapy. These micro structural changes influence mechanical properties and, therefore, behavior of bone and are critical to understand risk and mechanics of fracture of bone. Correlation between cortical bone strength and porosity, as a microscopic structural factor, has been examined frequently as a function of age and/or porosity. These studies have investigated the effect of porosity experimentally and have not studied the effect of porosity independently from other structural factors such as bone mineral density. In this study effect of porosity on elastic properties of human femoral cortical bone was studied independently using finite element analysis assuming transversely isotropic behavior in terms of elastic properties with the axis of elastic properties along the longitudinal axis of femur shaft. In this study, published standard mechanical tests for transversely isotropic materials were simulated using finite element computer simulation on models with different porosities. The developed finite element model utilized material properties based on the best fit regression in previously published articles. Pores’ size, shape and distribution were also modeled based on previous experimental studies. The finite element model, in general, predicted behavior of five independent elastic mechanical properties, namely, longitudinal Young’s modulus, transverse poisson’s ratio, transverse shear modulus, transverse Young’s modulus and longitudinal poisson’s ratio, as a function of porosity. Furthermore, effect of porosity on the elastic properties across various age groups was investigated using published data on age-related changes in bone porosity. Mathematical models based on Finite Element Analysis results have been developed using linear least square regression. These models show negative linear relationship between studied elastic properties of human femoral cortical bone and porosity. The Finite Element Analysis results compared well with the previously published experimental data. Furthermore, the results obtained show the elastic properties as functions of age for females and males. The predicted values for elastic properties are lower for men compared to women of age 20 to 40 years old. However, after the age of 44, elastic properties of femoral cortical bone for men are higher than women. The Finite Element Model developed in this study will help to create a clinical bone model for the prediction of fracture risk or the selection of suitable therapy in orthopedic surgery.

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