Acoustic Pressure Pipette Aspiration Method Combined with Finite Element Analysis for Isotropic Materials
Open Access
- 15 September 2019
- journal article
- research article
- Published by MDPI AG in Applied Sciences
- Vol. 9 (18), 3875
- https://doi.org/10.3390/app9183875
Abstract
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.Funding Information
- Austrian Science Fund (I 3806-B28)
- Deutsche Forschungsgemeinschaft (DO1247/9-1)
This publication has 52 references indexed in Scilit:
- Pipette aspiration applied to the characterization of nonhomogeneous, transversely isotropic materials used for vocal fold modelingJournal of the Mechanical Behavior of Biomedical Materials, 2013
- Simulation based estimation of dynamic mechanical properties for viscoelastic materials used for vocal fold modelsJournal of Sound and Vibration, 2011
- Assessment of local vocal fold deformation characteristics in an in vitro static tensile testThe Journal of the Acoustical Society of America, 2011
- Optical measurements of vocal fold tensile properties: Implications for phonatory mechanicsJournal of Biomechanics, 2011
- Spatially varying properties of the vocal ligament contribute to its eigenfrequency responseJournal of the Mechanical Behavior of Biomedical Materials, 2010
- Ranking vocal fold model parameters by their influence on modal frequenciesThe Journal of the Acoustical Society of America, 2009
- Influence of vocal fold stiffness and acoustic loading on flow-induced vibration of a single-layer vocal fold modelJournal of Sound and Vibration, 2009
- Characteristics of phonation onset in a two-layer vocal fold modelThe Journal of the Acoustical Society of America, 2009
- A simple-shear rheometer for linear viscoelastic characterization of vocal fold tissues at phonatory frequenciesThe Journal of the Acoustical Society of America, 2008
- The Application of a Homogeneous Half-Space Model in the Analysis of Endothelial Cell Micropipette MeasurementsJournal of Biomechanical Engineering, 1988