Abstract:The classical picture of middle ear (ME) transmission has the tympanic membrane (TM) as a piston and the ME cavity as a vacuum. In reality, the TM moves in a complex multiphasic pattern and substantial pressure is radiated into the ME cavity by the motion of the TM. This study explores ME transmission with a simple model, using a tube terminated with a plastic membrane. Membrane motion was measured with a laser interferometer and pressure on both sides of the membrane with micro-sensors that could be positione… Show more
“…Due to the complexity of these numerical models is difficult to conduct experimental–numerical work to obtain robust conclusion in this matter. Only with simplified and limited experimental setups we can fit the numerical model with the experimental data [ 21 ].…”
Section: Discussionmentioning
confidence: 99%
“…This aspect is very critical because of the topology of the membrane with a thickness of 70 μm. The validity of this approach has been tested with an experimental–numerical study [ 21 ]. Fig.…”
BackgroundThe main objective of this paper is to study the mechanical influence of the tympanic cavity (TC) in the auditory system (AS). It is done for a frequency range from 0.1 to 20 kHz and the pressure source was applied in the external ear canal (EEC) entrance.MethodsNumerical simulations were developed for seven different models by means of finite element model. On the basis of an EEC finite elements model, the additional elements are coupled and removed in order to evaluate the contribution of the TC. Tympanic membrane, ossicular chain, simplified cochlea and TC were modeled and simulated in four different combinations.ResultsPressure, velocity, and displacement measures were obtained in AS key points in order to be compared with experimental results. Umbo and stapes transfer functions have been represented.ConclusionsThe main conclusion is that we find evidence that the presence of the TC in the AS introduces a second resonance in middle ear transfer functions at frequencies above 3 kHz.
“…Due to the complexity of these numerical models is difficult to conduct experimental–numerical work to obtain robust conclusion in this matter. Only with simplified and limited experimental setups we can fit the numerical model with the experimental data [ 21 ].…”
Section: Discussionmentioning
confidence: 99%
“…This aspect is very critical because of the topology of the membrane with a thickness of 70 μm. The validity of this approach has been tested with an experimental–numerical study [ 21 ]. Fig.…”
BackgroundThe main objective of this paper is to study the mechanical influence of the tympanic cavity (TC) in the auditory system (AS). It is done for a frequency range from 0.1 to 20 kHz and the pressure source was applied in the external ear canal (EEC) entrance.MethodsNumerical simulations were developed for seven different models by means of finite element model. On the basis of an EEC finite elements model, the additional elements are coupled and removed in order to evaluate the contribution of the TC. Tympanic membrane, ossicular chain, simplified cochlea and TC were modeled and simulated in four different combinations.ResultsPressure, velocity, and displacement measures were obtained in AS key points in order to be compared with experimental results. Umbo and stapes transfer functions have been represented.ConclusionsThe main conclusion is that we find evidence that the presence of the TC in the AS introduces a second resonance in middle ear transfer functions at frequencies above 3 kHz.
“…2019, 9, The simulations of the models in ANSYS were made in two different situations: without load, and with radial load in the plane of the membrane (i.e. with pre-strain) [28]. The pre-strain of the membrane was introduced by means of an imposed radial displacement, which produces a radial deformation and the desired axial stress in the membrane.…”
Section: Numerical Methodology: Finite Element Analysismentioning
confidence: 99%
“…Another interesting parameter that can be evaluated is the ratio between the natural frequency of the modes and the frequency of the first mode (f n /f 1 ). This has been a useful parameter to evaluate the presence of pre-strain with experimental data [28]. If the natural modes of vibration are calculated analytically by Equation (1) or Equation (2), and these are referred to the first mode dividing by its value, the results are constants that can be calculated with the relations of the α constants for plate and membrane cases respectively (Table 3).…”
Section: Reference Case Studymentioning
confidence: 99%
“…Another field of study where this effect is manifest is the study of the mechanics of hearing. Based on different experimental studies [28] and simulation of the human hearing system [29] it has been observed that small levels of pre-strain in the system, particularly in the tympanic membrane, causes significant changes in the response. This issue is of great interest for our research group.…”
The dynamic behaviour of membranes has been widely studied by well-known authors for a long time. A clear distinction can be made between the behaviour of membranes without tension (plate case) and membranes subjected to large tension or pre-strain in their plane (membrane case). In classical theories, less attention has been paid to membranes subjected to a low level of tension, which solution is between both extreme cases. Recently, certain fields of research are demanding solutions for this intermediate behaviour. It is the case of membranes present in MEMS and sensor or the response of the tympanic membrane in mammals hearing system. In this paper, the behaviour of plates and circular membranes with boundary conditions clamped in the edges has been studied. The natural frequencies for both cases (plate and membrane) have been calculated using the solutions of the traditional theories and these have been compared with the numerical frequencies calculated by finite element analysis. The dynamic response of membrane with low tension, corresponding to a transition between these extreme behaviours, has also been calculated. A theoretical solution has been used complemented with a wide set of numerical finite elements calculations. The analytical and numerical solutions are very close, being the error made using both methods very low; nevertheless, there are no analytical solutions for the entire transition zone between the plate and membrane behaviour. Therefore, this range has been completed using finite element analysis. Broad ranges of geometric configurations have been studied. The transition behaviour of the membrane has been clearly identified. The main practical consequences of these results have been discussed, in particular focused on the response of the tympanic membrane.
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