The tympanic membrane in cross section: a finite element analysis

Lesser, T. H. J.; Williams, Keith R.

doi:10.1017/s0022215100104542

Cited by 24 publications

(17 citation statements)

References 13 publications

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“…The middle value is approximately one third of our baseline value of the pars-tensa Young's modulus, a pars-flaccida/pars-tensa stiffness ratio that has been used in other modelling studies (e.g. Lesser and Williams 1988;Koike et al 2002).…”

Section: Materials Propertiesmentioning

confidence: 95%

Finite-Element Modelling of the Acoustic Input Admittance of the Newborn Ear Canal and Middle Ear

Motallebzadeh

Maftoon

Pitaro

et al. 2016

JARO

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Admittance measurement is a promising tool for evaluating the status of the middle ear in newborns. However, the newborn ear is anatomically very different from the adult one, and the acoustic input admittance is different than in adults. To aid in understanding the differences, a finite-element model of the newborn ear canal and middle ear was developed and its behaviour was studied for frequencies up to 2000 Hz. Material properties were taken from previous measurements and estimates. The simulation results were within the range of clinical admittance measurements made in newborns. Sensitivity analyses of the material properties show that in the canal model, the maximum admittance and the frequency at which that maximum admittance occurs are affected mainly by the stiffness parameter; in the middle-ear model, the damping is as important as the stiffness in influencing the maximum admittance magnitude but its effect on the corresponding frequency is negligible. Scaling up the geometries increases the admittance magnitude and shifts the resonances to lower frequencies. The results suggest that admittance measurements can provide more information about the condition of the middle ear when made at multiple frequencies around its resonance.

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Section: Materials Propertiesmentioning

confidence: 95%

Finite-Element Modelling of the Acoustic Input Admittance of the Newborn Ear Canal and Middle Ear

Motallebzadeh

Maftoon

Pitaro

et al. 2016

JARO

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show abstract

“…The very high value of 20 GPa reported in Table 3 of Volandri et al (2011) was a typographical error (GPa rather than MPa) in the original paper by Gentil et al (2005) (personal communication with Gentil). The very low value of 1.5 MPa used by Lesser and Williams (1988) was for a 2-D model. The very low values used by Funnell and Laszlo (1978) and Funnell (2001) for Ec were intended to be extreme examples of anisotropy, not realistic estimates.…”

Section: Baseline Materials Propertiesmentioning

confidence: 99%

Finite-Element Modelling of the Response of the Gerbil Middle Ear to Sound

Maftoon

Funnell

Daniel

et al. 2015

JARO

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We present a finite-element model of the gerbil middle ear that, using a set of baseline parameters based primarily on a priori estimates from the literature, generates responses that are comparable with responses we measured in vivo using multi-point vibrometry and with those measured by other groups. We investigated the similarity of numerous features (umbo, pars-flaccida and pars-tensa displacement magnitudes, the resonance frequency and break-up frequency, etc.) in the experimental responses with corresponding ones in the model responses, as opposed to simply computing frequency-by-frequency differences between experimental and model responses. The umbo response of the model is within the range of variability seen in the experimental data in terms of the low-frequency (i.e., well below the middle-ear resonance) magnitude and phase, the main resonance frequency and magnitude, and the roll-off slope and irregularities in the response above the resonance frequency, but is somewhat high for frequencies above the resonance frequency. At low frequencies, the ossicular axis of rotation of the model appears to correspond to the anatomical axis but the behaviour is more complex at high frequencies (i.e., above the pars-tensa break-up). The behaviour of the pars tensa in the model is similar to what is observed experimentally in terms of magnitudes, phases, the break-up frequency of the spatial vibration pattern, and the bandwidths of the high-frequency response features. A sensitivity analysis showed that the parameters that have the strongest effects on the model results are the Young's modulus, thickness and density of the pars tensa; the Young's modulus of the stapedial annular ligament; and the Young's modulus and density of the malleus. Displacements of the tympanic membrane and manubrium and the lowfrequency displacement of the stapes did not show large changes when the material properties of the incus, stapes, incudomallear joint, incudostapedial joint, and posterior incudal ligament were changed by ±10 % from their values in the baseline parameter set.

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“…The model used spring and damping to represent TM impedance effect by the floor of stapes and cochlea. Lesser et al [8,9] used FE method to study the mechanical properties of human by setting up a FE model of 2-D cross section on TM and the malleus to analyze the static displacement of those two. Subsequently, Williams et al [10,11] changed variable parameters of TM in FE model to study middle ear model characteristics under external forces in a fixed frequency.…”

Section: Introductionmentioning

confidence: 99%

Free vibration model and theoretical solution of the tympanic membrane

Chen

Al-Furjan

et al. 2016

Computer Assisted Surgery

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Myringoplasty is one of the routine surgeries in the treatment of tympanic membrane (TM) perforation. Since the gross anatomical structure of the middle ear cannot be simulated in clinical practice, the surgery is mainly performed by experience and expertise. Based on the mechanical properties of TM, four hypotheses are presented where TM is simplified as a sectorial annulus membrane. This paper proposes a free vibration model of TM whose natural frequency of free vibration and the analytical expressions of corresponding natural vibration mode are obtained by variables separation method and Bessel function. Compared with the ANSYS numerical results, it shows that natural frequency calculated by finite element (FE) method is slightly higher because of the increase of model stiffness by ignoring high-order quantity. Compared with the experimental data from volunteers, it shows that the first-order, second-order and third-order principal resonances in the test are the combined effects of multiple natural frequencies and natural vibration modes instead of the single one. The theoretical model deduced in this paper is in higher precision with comparatively fewer parameters. It provides more precise mechanical reference to myringoplasty by calculating the response of the normal human ear.

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The tympanic membrane in cross section: a finite element analysis

Cited by 24 publications

References 13 publications

Finite-Element Modelling of the Acoustic Input Admittance of the Newborn Ear Canal and Middle Ear

Finite-Element Modelling of the Acoustic Input Admittance of the Newborn Ear Canal and Middle Ear

Finite-Element Modelling of the Response of the Gerbil Middle Ear to Sound

Free vibration model and theoretical solution of the tympanic membrane

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