Measurement and Analysis of the Material Properties and Oscillation Characteristics of Synthetic Vocal Folds

Weiß, Sandra; Sutor, Alexander; Ilg, J.; Rupitsch, Stefan J.; Lerch, Reinhard

doi:10.3813/aaa.918938

Cited by 11 publications

(13 citation statements)

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“…The elastic modulus was determined by a simple analytical approximation (1). We improved the setup by using a miniaturised loudspeaker as a replacement for the pistonphone, which was used by Zörner et al and Weiss et al [39,40], in order to produce an acoustic pressure at predefined frequencies inside the pipette. The bottom end of the pipette was placed on the surface of the sample perpendicularly in the two different contact boundary conditions.…”

Section: Methodsmentioning

confidence: 99%

“…In the previous studies by Weiss et al [40] and Zörner et al [39], the excitation pressure was kept constant over the whole frequency range. These studies showed that the calculated elastic modulus does not depend on the variation of the excitation pressure amplitude.…”

Section: Influence Of the Excitation Pressure Variationsmentioning

confidence: 99%

“…The previous studies [33,39,40] show that the contact force between the pipette tip border and the sample surface has an impact on the measurement, while the effect of the pipette tip wall compression force and friction on the sample surface behaviour has not been studied yet. In this present study, the measurement and the simulation were done in the two boundary approaches, connected pipette and pipette with gap conditions.…”

Section: Effect Of the Compression Force On The Measurementmentioning

confidence: 99%

“…Weiss et al [40][41][42] enhanced the setup of Zörner et al [39] to suggest a reliable pipette aspiration method for spatially-resolved material characterization of synthetic vocal folds over a frequency range of 50 Hz to 700 Hz. Unlike the Aoki et al [33] method to counteract the pipette wall force on the sample surface, Weiss et al [40] limited the force to 0.1 N for all the mixtures in the frequency range. However, those measurement setups are not accurate enough to measure frequency-dependent material properties of anisotropic and inhomogeneous materials as existent in vocal folds.…”

Section: Introductionmentioning

confidence: 99%

“…The first study [39] used the Aoki et al [33] analytical approximation (see Equation (1)) to calculate the modulus of elasticity, which was developed for a static measurement; thus, it does not take into account all the impact factors of a dynamic measurement setup. The main drawback of the previous studies [39,40] is the large scale of the experimental setup that is not appropriate for a clinical use, which is the long-term goal of research in this area. Therefore, those tasks will be addressed with innovative measurement setups within this present study.…”

Section: Introductionmentioning

confidence: 99%

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Acoustic Pressure Pipette Aspiration Method Combined with Finite Element Analysis for Isotropic Materials

2019

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A measurement setup combined with a numerical simulation by a linear finite element analysis is presented as a method to determine the elastic modulus of both artificial and real tissue as a function of frequency. At the end, the future goal is to develop and validate the method to measure the elastic modulus of in-vivo human vocal folds over the human phonation frequency range. In the present study, a miniaturized acoustic pressure pipette aspiration technique is developed to measure the material characteristics of an isotropic silicone specimen with similar characteristics as human vocal folds. In previous studies, friction and compression force effects of the pipette tip wall on the surface of the sample and the radius of the pipette were not investigated. Moreover, the large scale of the measurement setups made them impossible to use for clinical applications. Therefore, two different pipette sample cross-section boundary conditions and two different pipette radii were used. With the aim of ensuring reliable results, we tested our method with pipettes of two different radii on four silicone samples with different consistencies over a frequency range of 50–500 Hz. The simulation verified the measurement results in which the strong dependency of the elastic modulus on the excitation frequency, radius of the pipette, the pipette tip compression force and friction was revealed. By the simulation results, two different frequency dependent equations were developed for calculating elastic modulus of the silicone mixtures in the two cross-section boundary conditions. It was concluded that using a very small gap in between the pipette tip and the specimen can cancel the impact of the pipette tip force and friction which are the major cause of uncertainty. However, if a connection between the pipette and the surface is unpreventable, the contact force should be restricted to be absolutely zero.

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Section: Methodsmentioning

confidence: 99%

Section: Influence Of the Excitation Pressure Variationsmentioning

confidence: 99%