A critical review of the intrinsic nature of vortex-induced vibrations

Past, present and future of nonlinear system identification in structural dynamics

Computational methods in optimization considering uncertainties – An overview

In this study, a three-dimensional finite-element model (FEM) of the human middle ear was established, including features of the middle ear which were not considered in the previous model, i.e., the ligaments, tendons, I-S joint, loading of the cochlea, external auditory meatus (EAM), middle-ear cavities, etc. The unknown mechanical properties of these parts and the boundary conditions were determined so that the impedance obtained from the FEM analysis resembled the measurement values. The validity of this model was confirmed by comparing the motion of the tympanic membrane and ossicles obtained by this model with the measurement data, and the effects of the newly considered features on the numerically obtained results were examined. By taking the ligaments and tendons into account and assuming that the cochlea acts as a damper, with this model it was possible to realistically reproduce complex ossicular chain movement. It was found that the middle-ear cavities did not affect the vibration mode of the tympanic membrane. Although the EAM enhanced the sound pressure applied to the tympanic membrane compared with that at the entrance of the EAM, the pressure distribution on the surface of the tympanic membrane was not affected by the EAM.

Modeling of the human middle ear using the finite-element method

A finite element model of an ear stored on a computer readable medium having logic representing a three-dimensional geometric model of the ear; logic for meshing individual anatomical structures of the ear accounting for whether the anatomical structures include at least one of air, liquid material and solid material; logic for assigning material properties for each anatomical structure based on at least one physical property of each anatomical structure; logic for assigning boundary conditions for some of the anatomical structures indicative of interaction between such anatomical structures; and logic for employing acoustic-structural coupled analysis to the anatomical structures of the ear to generate data indicative of the acoustic effect on mechanical vibration transmission in the ear. Various embodiments of 'one-chamber' and 'two-chamber' analyses and models are described.

3-dimensional finite element modeling of human ear for sound transmission

Estimating human exposure to transport noise in central Dublin, Ireland.

In this study, a computer-based method called finite-element analysis is used to predict the forced-frequency response of the ear, with and without an ossicular replacement prosthesis (PORP 0362, Xomed Surgical Products). The method allows visualisation of the dynamical behaviour of the tympanic membrane (TM) and of the ossicles. The finite-element model is fully three-dimensional and includes both ligaments and muscles, and accounts for damping caused by the TM, ligaments, incudostapedial joint and the fluids of the inner ear. For validation, comparison is made with experimental measurements of umbo displacement taken from the literature. The translation and rotation (both anterior-posterior and inferior-superior) of the stapedial footplate are investigated. It is predicted that the translatory motion of the footplate decreases with increasing frequency, except when the frequency of the acoustic signal matches the natural frequencies of the ossicular chain or outer ear canal. The tilting motion of the stapedial footplate is also predicted to depend on frequency of excitation. The presence of a prosthesis changes the dynamical response considerably by shifting the natural frequencies of the ossicular chain. Ratios of stapes motion with and without the prostheses are plotted as a function of frequency allowing this effect to be clearly observed.

Henry J. Rice

Papers

Estimating human exposure to transport noise in central Dublin, Ireland.

Vibro-acoustic modelling of the outer and middle ear using the finite-element method

Vibro-acoustic modelling of the outer and middle ear using the finite-element method

The development of a practical framework for strategic noise mapping

Implementation of the EU environmental noise directive: lessons from the first phase of strategic noise mapping and action planning in Ireland.